Module 4 – Biodiversity, evolution and disease

Question 1

C10) What is the meaning of classification

Answer 1

The process of organising living organisms into groups. The organisms within each group share similar features

Question 2

C10) what is a taxonomic group

Answer 2

Seven groups ordered in hierarchy

Kingdoms are the biggest and broadest taxonomic group and species being the smallest and most specific classification

Hierarchical classification systems are also referred to as linnaean classification proposed by carl Linnaeus

Because of the study of genetic material scientists added domains at the top of the hierarchy

Question 3

C10) why do scientists classify organisms

Answer 3

To identify species - by using clearly defined systems of classification the species an organism belongs to can be easily identified

To predict characteristics - if several members in a group have a specific characteristic so will others in the same group

To find evolutionary links - species in the same group probably share characteristics because they evolved from a common ancestor

By using a single classification system scientist worldwide can share research. Links between different organisms can be seen even if they live on different continent

Question 4

C10) How are organisms classified

Answer 4

The classification system begins by separating organisms into three domains- Archaea, bacteria, Eukarya.
As you move down the hierarchy there are more groups at each level but fewer organisms in each group.
The organisms in each group become more specific and share more characteristics

The system ends with organisms being classified as individual species.

Question 5

C10) what is the definition of species

Answer 5

A group of organisms that are able to reproduce to produce fertile offspring

Question 6

C10) what are the problems with common names of organisms

Answer 6

They are based on physical characteristics or behaviours.

They are not very useful for scientists working internationally as organisms may have more than one common name and different names in different languages

Common names do not provide information about the relationship between organisms

So we use the binomial naming system

Question 7

C10) What are the five kingdoms

Answer 7

Prokaryotae

Protoctista - Unicellular eukaryotes
Fungi - yeast, mould and mushrooms
Plantae
Animalia

Question 8

C10) What are the general features of prokaryotae

Answer 8

Unicellular

No nucleus or other membrane - bound organelles-a ring of naked DNA

No visible feeding mechanism - nutrients are absorbed through the cell walls

Question 9

C10) what are the General features of protoctista

Answer 9

Unicellular

A nucleus and other membrane-bound organelles

Nutrients are acquired by photosynthesis, digestion of other organisms or both

Question 10

C10) what are the General features of fungi

Answer 10

Unicellular or multi cellular

A nucleus and other membrane-bound organelles and a cell wall

Nutrients are acquired by absorption mainly from decaying material

Question 11

C10) what are the general features of plantae

Answer 11

Multi cellular

Enucleation other membrane-bound organelles including chloroplast

Nutrients are acquired by photosynthesis

Question 12

C10) What are the General features of Animalia

Answer 12

Multi cellular

Enucleation other membrane-bound organelles

Nutrients acquired by ingestion

Question 13

C10) Why has there been a change in the classification system

Answer 13

Because of the study of genetics

DNA determines the proteins that are made which codes for the organisms characteristics. If the characteristics change then the DNA must have also changed. By comparing the similarities in DNA and proteins of different species scientists can discover relationships between them.

Question 14

C10) what is the three domains system

Answer 14

Was proposed by carl Woese

Domain was a further level of classification at the top of the hierarchy

Groups organisms using differences in the sequence of nucleotides in the cells ribosomal RNA as well as the cells membrane lipids structure and the sensitivity to antibiotics

Organised into three domains and six kingdoms

Question 15

C10) What are the three domains

Answer 15

Eukarya

Have a 80s ribozymes and are they polymerise contain 12 proteins

Archaea

Have 70 S ribosomes and RNA polymerase of different organisms containing between 8 and 10 proteins

Bacteria

Have 70 S ribosomes and RNA polymerise contain five proteins

Question 16

C10) what are the six kingdoms of the three domains system

Answer 16

Eubacteria, Archaebacteria, pritoctista, plantae, fungi, Animalia

Question 17

C10) what are Eubacteria and Archaebacteria

Answer 17

Eubacteria

Known as true bacteria, found in all environments.
Most bacteria are in this kingdom

Archaebacteria

Known as ancient bacteria, can live in extreme environments.
Including hot thermal vents, anaerobic conditions and highly acidic places

Question 18

C10) What is Phylogeny and phylogenetics

Answer 18

Phylogeny is the evolution of relationships between organisms

The study of the evolutionary history of groups is known as phylogenetics

Question 19

C10) how are phylogenetic trees made

Answer 19

Are produced by looking at similarities and differences in species physical characteristics and genetic make up

much in evidence gained from fossil feels

Question 20

C10) what are the advantages of phylogenetic classification

Answer 20

Phylogeny is done without reference to classification.
Classifications and use knowledge of phylogeny in order to confirm the classification groups are correct or cause them to change

Phylogeny produces a continuous tree whereas classifications required discrete taxonomy groups so scientists are not forced to put organisms into a specific group that they do not fit into

The historic nature of classifications can be misleading as it implies different groups within the same rank are equivalent

Question 21

C10) how did The theory of evolution develop

Answer 21

Most people believed in the Bible and the creation story

Charles Darwin read a book written by his friend Charles Lyell as a result came up with the idea that evolution was a slow process one in which small changes accumulated over time

Proved this theory using finches in the Galapagos Islands because different finches in different islands had different beaks and claws of different sizes and shapes by observing this he found out that it was linked to the food available on each island

Concluding that a bird born with a beak most suited to the food available would survive longer than a bird who didn’t. Therefore it would have more offsprings passing on the advantages characteristics

A different man called Alfred Wallace had a similar idea and so they both wrote on “the origins of species”

Question 22

C10) What are the evidence for evolution

Answer 22

Palaeontology: Study of fossil fuels and fossil records

Comparative anatomy: studying of similarities and differences between organisms anatomy

Comparative biochemistry: Similarities and differences between the Chemical make up of an organism

Question 23

C10) That are the evidence provided by palaeontology

Answer 23

Fossils form over time to make strata. The fossils that are on top are the youngest and the fossils near the bottom of the crust are the oldest therefore showing evolution of organisms

Fossils allow relationships between extinct and living organisms to be investigated

Fossils of simplest organisms like bacteria are found in the oldest rocks while fossils of more complex organisms such as vertebrates are found in more recent rocks supporting the evolutionary theory that simple lifeforms gradually evolved over millions of years to more complex ones

By studying similarities in the anatomy of fossil organisms scientists can show how closely related organisms have evolved from the same ancestry

Question 24

C10) what are the limits of palaeontology

Answer 24

The fossil records are not completed for example Many softbodied organisms have decomposed before they had a chance to become fossils.

Many fossils have been destroyed by the earths tectonic movements

Question 25

C10) How has comparative anatomy of homologous structures helped prove evolutionary theory

Answer 25

Homologous structures are structures that appear or function significantly different in different organisms but has the same underlying structure

For example the bone structure of the limbs in the flying vertebra are similar to a walking vertebra or a swimming vertebra but their functions have changed this could be due to being evolved from a common ancestor

Homologous structures provide evidence of divergent Evolution this Describes how different species with a different set of adapted features have evolved from a common ancestor

Question 26

C10) How has comparative biochemistry helped to prove the evolution theory

Answer 26

Is the study of similarities and differences in the proteins and other chemicals that control life processes.

For example cytochrome C (involved in respiration) and ribosomal RNA

To discover how closely related to species are the molecular sequence is compared by looking at the DNA bases or the order of amino acids. The number of differences that exist are plotted against the rate the molecule undergoes natural base pairs substitution. From this they can estimate the point where the two species shared a common ancestor.

Species who are closely related have similar DNA and proteins whilst distantly related have fewer similarities

Question 27

C10) What are the two causes of variation

Answer 27

And organisms genetic material – difference in the genetic material of an organism inherited from its parents lead to genetic variation

The environment in which the organism lives - causes environmental variation

Question 28

C10) what are the two types of variation

Answer 28

Interspecific variation-between members of different species

Intraspecific variation – between organisms within a species

Question 29

C10) what are three genetic causes of variation

Answer 29

Alleles - Different alleles produce different effects. Individuals in a species population may inherit different alleles of a gene

Meiosis - gametes are produced by meiosis in organisms that break produce sexually. Each gamete receives half the genetic information of a parent cell. Genetic material inherited from the two parents is mixed up by independent Saltman and crossover. Leading to gametes of an individual showing variation

Chance - many different gametes are produced from the parental genome. During sexual reproduction it is the result of chance as to which two combinations-random fertilisation. Individuals produce therefore differ from siblings as each contain a unique combination of genetic material

Question 30

C10) how can asexual reproduction introduce variation

Answer 30

Asexual reproduction results in the production of clones – individuals that are genetically identical to parents

Genetic variation can only be increased and these organisms as a result of mutation

Question 31

C10)What are environmental causes of variation

Answer 31

All organisms are affected by the environment in which they live, although plants may be affected to a greater degree than animals due to the lack of mobility

Question 32

C10) How can Variation be detected

Answer 32

With the use of twins who are split up at birth and sent to different environments

Question 33

C10) environmental and genetic causes

Answer 33

most cases of variation are caused by a combination of both environmental and genetic factors

For instance the height of a person can be genetic as it can be influenced by your parents height but also environmental as a good diet is needed to grow above average height

Question 34

C10) what is discontinuous variation

Answer 34

Characteristic that can only result in certain values

No in between value

Variation determined purely by genetic factors Falls into this category.

Normally represented using a bar chart

Controlled by a single gene

Question 35

C10) what is continuous variation

Answer 35

Characteristic that can take any value within a range

not controlled by a single gene but a number of genes

Also often influenced by environmental factors

Continuous variation data is collected in a frequency table and plotted on a histogram then a curve is drawn onto the graph to show the trend

Question 36

C10)What is the normal distribution curve

Answer 36

When continuous variation data is plotted onto a graph usually result in the production of a bell shaped curve known as the normal distribution curve

Question 37

C10) characteristics of a normal distribution

Answer 37

The mean, mode and median are the same

The distribution has a characteristic bell shape, which is symmetrical about the mean

50% of values are less than the mean and 50% or greater than the mean

Most values like close to the mean value - number of individuals are at the extremes are low

Question 38

C10) what a standard deviation

Answer 38

Is a measure of how spread out the data is

The greater the standard deviation the greater the spread of the data

A characteristic which has a high standard deviation has a large amount of variation

Question 39

C10) what will you find when you calculate standard deviation of data in a normal distribution curve

Answer 39

68% of values are within one standard deviation of the main

95% of values are within two standard deviations of the main

99.7% of values are within three standard deviations from the mean

Question 40

C10) what is the students t test

Answer 40

Used to compare the means of data values of two populations

Question 41

C10) what is the Spearman‘s rank correlation coefficient

Answer 41

Used to consider the relationship between two sets of data

Question 42

C10) how do you figure out the degree of freedom

Answer 42

(n1-n2)-2

Where n1 = population one, n2 = population 2

Question 43

C10) what are adaptations

Answer 43

Characteristics that increase in organisms chance of survival and reproduction in its environment

Many adaptations fall into more than one category

Question 44

C10) what are the different types of adaptations

Answer 44

Anatomical adaptations- physical features, internal and external

Behavioural adaptations- the way an organism acts. This can be innate (instinctive) through genes or learnt from their parents

Psychological adaptations- processes that take place inside an organism

Question 45

C10) What are some examples of anatomical adaptations

Answer 45

Body covering- animals have a number of different body coverings are such as hair, scales, spines, feathers and shells.
Can help: organisms to fly such as feathers on birds, help to stay warm such as polar bears, provides protection such as snail shells. Thick waxy layer on plants prevent water loss and spikes can deter herbivores and protect the tissue from some damage

Camouflage- the outer colour of an animal allows it to blend into its environment making it harder for predators to spot it.

Teeth- The shape and type of teeth present in an animal jaw are related to its diet. herbivoresSuch as sheep have continuously growing molars for chewing Tough grass and plants. Carnivores have sharp long canines to kill pray and tear meet

Mimicry- copying other animals appearance or sound allows an harmless organism to fool predators into thinking it is poisonous or dangerous

Question 46

C10) How are marram grass adapted to reduce the rate of transpiration

Answer 46

It’s a Xerophyte, A plant that has adapted to live in an environment with a little water

Curled leaves to minimise the surface area of moist tissue exposed to the air and protect the leaves from the wind

Hairs on the inside surface of the leaves to trap moist air close to the leaf reducing the diffusion gradient

Stomata sank into pits which make them less likely to open and lose water

A thick waxy cuticle on the leaves and stems reducing water loss through evaporation

Question 47

C10) what are some behavioural adaptations

Answer 47

Survival behaviours- a rabbit freezes when they think they have been seen

Courtship- many animals exhibit elaborate courtship behaviour to attract a mate

Seasonal behaviour-enable organisms to cope with changes in the environment

Question 48

C10) what are different types of seasonal behaviours

Answer 48

Migration-animal moves from one region to another and then back again when environmental conditions are more favourable. This may be for a better climate or a source of food

Hibernation-a period of inactivity in which an animal‘s body temperature, heart rate and breathing slow down to conserve energy reducing the animals requirement for food

Question 53

C10) what are some physiological adaptations

Answer 53

Poison production- reptiles produce venom to kill their prey and many plants produce poison in their lives to protect themselves

Antibiotic production– some bacteria produce antibiotics to kill other species of bacteria in the surrounding areas

Question 53

C10) What are Analogous structures

Answer 53

The tailfin of a whale and a fish perform the same role, when you look at them in detail their structures are very different

They have adapted to perform the same function but have a different genetic origin

Question 54

C10) what is convergent evolution

Answer 54

When unrelated species begin to share similar traits

Similarities involved because the organism adapt to similar environments or other selection pressures

Can also happen in plant species

Question 54

C10)What is the meaning of selection pressure

Answer 54

These are factors that affect the organisms chance of survival or reproductive success (the ability to produce fertile offspring)

Question 55

C10) what are the steps of natural selection

Answer 55

1) organisms within a species show variation in their characteristics that are caused by differences in their genes-new alleles can arise by mutation
2) organisms whose characteristics are best adapted to a selection pressure such as predation, competition or disease have an increased chance of surviving and successfully reproducing. Less well adapted organisms die or failed to reproduce- survival of the fittest
3) Successful organisms pass the allele including the advantages Characteristic onto there offspring. Organisms that possess the non-advantages allele are less likely to successfully pass it on.
4) process is repeated for every generation. Over time the population of individuals with the advantages adaptation increase. Therefore the frequency of the allele that code for these particular characteristics increase in the population gene pool
5) Over many generations and often involving multiple genes this process can lead to the evolution of a new species

Question 56

C12) what are the different types of pathogens

Answer 56

Bacteria

Viruses

Protista

Fungi

Question 57

C12) what are the eats to classify bacteria

Answer 57

By their basic shape - they can be rod shaped, spiracle,, shapes, spiralled and corkscrewed

By the cell wall - the two main types of bacteria cell walls have different structures and react differently to gram staining. Gram positive bacteria look purple/blue.. Gram negative bacteria appear red. This is useful because the type of cell walls affects how bacteria react to different antibiotics

Question 58

C12) what are the properties of viruses

Answer 58

Viruses are nonliving infectious agents with the basic structure of some genetic material surrounded by protein

Viruses invade living cells where the genetic material of the virus takes over the host cell to make more viruses

Viruses reproduce rapidly and evolved by developing adaptations to their hosts making them successful pathogens

Question 59

C12) what is bacteriophages

Answer 59

They are viruses that attack bacteria by taking over the bacterial cells and using them to to replicate destroying the bacteria at the same time

People have used bacteriophages to identify and treat some diseases

Scientists consider viruses to be the ultimate parasite

Question 60

C12) what are the properties of Protista

Answer 60

Has a wide variety of feeding methods

Include single celled organisms and cells grouped into colonies

The Protista which cause disease are parasite -they use people animals as the host organism

Question 61

C12) what are the properties of fungi

Answer 61

Fungal disease is not a big problem for animals but are devastating to plants

Are eukaryotic organisms, often multicellular,

Many fungi are saprophytes meaning they feed on dead and decaying matter but some fungi are parasites feeding on living plants and animals

Parasite bacteria cause communicable diseases because fungal infections often affect the leaves of the plants which stop them photosynthesising leading to killing of the plant

Fungi reproduce with millions of tiny spores which spread huge distancesThis means they can spread widely and rapidly through plant crops

Question 62

C12) What are the different methods of action for pathogens

Answer 62

Destroying the host tissue directly

producing toxins which damage host tissue

Question 63

C12) How do you pathogen is damaged the host tissue directly

Answer 63

The viral genetic material gets into the host cell and is inserted into the host DNA. The virus uses the host cells to make new viruses which burst the cell destroying it and then spreading the infection to other cells

Protester take over cells and destroy them open as the new generations emerge but they do not take over the genetic material of the cell. They digests and use the cell contents to reproduce

Fungi digest living cells and destroy them. Combining with the response from the body to the damage, fungi gives symptoms

Question 64

C12) What are the different plant diseases

Answer 64

Ring rot

Tobacco mosaic virus

Potato blight

Black sigatoka

Question 65

C12) what are the facts around Ring rot

Answer 65

A bacterial disease caused by gram-positive bacteria

Damages leaves, tubers and fruit

There is no cure, once Ring rot infect a field it cannot be used again for at least two years

Question 66

C12) What are the facts around tobacco mosaic virus

Answer 66

A virus that infects tobacco plants and around 150 other species

Damages leaves, flowers and fruit.

Stunting growth and reducing yield can lead to total crop lost

Resistant crops trains are available but there is no cure

Question 67

C12) what are the facts around potato blight

Answer 67

Caused by the fungus like protests.

Damaging leaves, tubers and fruits

No cure but resistant strains, carefully manageable and chemical treatment to reduce infection risk

Question 68

C12) what are the facts around the black sigatoka

Answer 68

Banana disease caused by fungus

Attacks and destroys the leaves. Digests the cells turning the leaves black.

If plants are infected it can cause a 50% reduction in yield

Resistant strains being developed, good husbandry and fungicide treatment can control the spread of the disease, no cure

Question 69

C12) What are the Animal diseases

Answer 69

Tuberculosis

Bacterial meningitis

HIV/AIDS

Influenza

Malaria

Ring worm

Athletes foot

Question 70

C12) what are the facts around tuberculosis

Answer 70

Bacterial disease

Damages and destroys lung tissue and suppresses the immune system, body is less able to fight of other diseases

In people TB is both curable by antibiotics and a preventable by improving living standards and vaccinating

Question 71

C12) what are the facts around bacterial meningitis

Answer 71

Bacterial infection of the meninges of the brain, can spread into the rest of the body causing septicaemia and rapid death

Affects very young children and teenagers aged 15 to 19

Symptoms, a blotchy red/purple rash that does not disappear when glass is placed against it. This is symptoms of septicaemia.

Antibiotics will cure the disease if delivered early. Vaccines can protect against forms of bacterial meningitis

Question 72

C12) what are the facts around HIV and AIDS

Answer 72

AIDS is caused by HIV

Target the T-helper cells in the immune system of the body. Gradually destroying the immune system so that person is open to other infections.

HIV/AIDS is a retrovirus with RNA as its genetic material. Contains the enzyme reverse transcription

Past on by bodily fluids

No vaccine and no cure but anti-retroviral drugs slow the progress of the disease

Question 73

c12) what are the facts around influenza

Answer 73

A viral infection of the ciliated epithelium cells in the gases exchange system

Can be fatal especially to young children and old people and people with chronic illnesses.

Three main strains-A, B and C

A is the most virulent and are classified further by the proteins on the surface

They mutate regularly but the changes are usually small so having flu one year can have some immunity for the next

Sometimes the changes in the surface antigens can lead to a flu epidermic or pandemic

Vulnerable groups are vaccinated annually

No Cure

Question 74

c12) What are the facts around malaria

Answer 74

Caused by the protoctista and spread by bites of infected mosquitoes

They reproduce inside a female mosquitoes need to take blood for protein before she lays eggs there for passing on the parasite

Invade the red blood cells, liver and even the Brain

No vaccine and limited cause but prevention measures are effective

Mosquitoes can be destroyed by insecticide and removing the standing water they breed in or by using mosquito nets preventing them from biting people and spreading the disease

Question 75

C12) what are the facts around ring worm

Answer 75

A fungal disease affecting mammals

Different fungi affect a different species

Causes grey-white, crusty, infectious, circular areas ofSkin

Not damaging but looks unsightly and may be itchy

Antifungal creams are effective cures

Question 76

C12) what are the facts around athletes foot

Answer 76

Human fungal disease

Form of human ringworm that grows on and digests the warm moist skin between the toes

Causes cracking and scaling which is itchy and may become sore

Antifungal cream is effective cure

Question 77

C12) what are forms of direct transmission of a communicable disease in animals

Answer 77

Direct contact:

Kissing or any contact with bodily fluids from another person (STI)
Direct skin to skin contact (Athletes foot)
Microorganisms from faeces transmitted on the hand (Diarrhoeal disease)

Inoculation:

Through a break in the skin (HIV/AIDS)
From an animal bite (rabies)
Through a punch a wound or sharing of needles (septicaemia)

ingestion:

Taking in contaminated food or drink or transferring pathogens to the mouth from the hands (Diarrhoeal disease)

Question 78

c12) what are the different indirect transmission pathways of a communicable disease in animals

Answer 78

Fomites:

Inanimate objects such as bedding, socks or cosmetics can transfer pathogens (athletes foot)

Droplet infections:

Miniature droplets of saliva and mucus are expelled from your mouth as you talk, cough or sneeze. Droplets containing pathogens are breathed in my healthy individuals they can become infected (Influenza)

Vectors:

Transmits communicable pathogens from one house to another. Often animals but not always (Mosquitoes transmit malaria)
Water can also act as a vector for diseases (diarrhoeal disease)

Question 79

C12) what are factors affecting the transmission of communicable diseases in animals

Answer 79

Overcrowded living and working conditions

Poor nutrition

A compromised immune system including having HIV/AIDS or needing immunosuppressant drugs

Poor disposal of waste provide breeding grounds for vectors

Climate change introduced new vectors a new diseases (malaria moving towards the UK due to temperature change)

Culture and infrastructure - in many countries traditional medical practices can increase transmission

Socio-economic factors - a lack of trained health workers and insufficient public warning when there is an outbreak of disease can increase transmission rate

Question 80

C12) What are direct transmission of pathogens between plants

Answer 80

Involves direct contact of a healthy plant with any part of a diseased plant examples include ring rot tobacco mosaic virus and blight

Question 81

C12) what are the different indirect transmission pathways of a communicable disease in plants

Answer 81

Infect the plants often leaves pathogens or reproductive spores in the soil

Which would infect the next cop

Examples include tobacco mosaic virus, Ring Road and black Sigatoka

Question 82

C12) what are the different factors that affect the transmission of communicable diseases within plants

Answer 82

Wind- bacteria, viruses and fungi spores can be carried by the wind (Black sigatoka blown between Caribbean Islands)

Water- spores swim in the surface film of water water on leaves, raindrops splashes carry pathogens and spores (spores of potato blight which swim over films of water on the leaves )

Animals- insects and birds carry pathogen and spores from one plant to another as they feed.

Humans-Pathogens and spores are transmitted by hands, clothing, fomites. (Tobacco mosaic virus survives for years on tobacco plants)

Question 83

C12) What factors affect the transmission of communicable diseases in plans

Answer 83

Planting varieties of crops that are susceptible to disease

Overcrowding increases the likelihood of contact

Poor minerals nutrition reduces resistance of plants

Damp, warm conditions increase the survival and spread of pathogens and spores

Climate change – anincreased rainfall and wind promote the spread of disease. Changing conditions allow animal vectors to spread to new areas.

Question 84

C12) how did plants recognise an attack from a pathogen

Answer 84

Plants are not passive

Receptors in the cell respond to molecules from the pathogen or to chemicals produced when the plant cell wall is attacked

This stimulates the release of signalling molecules that turn on genes in the nucleus

This triggers a cellular response which include producing defensive chemicals, sending alarm signals to unaffected cells to trigger their defences and physically strengthening the cells

Question 85

C12) what are some physical defences of a plant when it is attacked by a pathogen

Answer 85

When a plant is attacked by a pathogen it produces high levels of Celulose

Celulose is synthesised and deposited between the cell walls and the cell membrane in cells next to the infected cells. They act as barriers preventing the pathogen entering the plant cell around infection site

Celulose continues to be deposited in the cell walls after the initial infection but lignum is added in making the mechanical barrier to invasion even thicker and stronger

Celulose blocks sieve plates in the phloem, ceiling of the infected parts and preventing the spread of pathogens

Celulose is deposited in the plasmodesmata between infected cells and their neighbours, ceiling them off from healthy cells and preventing the spread of the pathogen

Question 86

C12) what are some chemical defences of a plant when it is attacked by a pathogen

Answer 86

Plants produce powerful chemicals that either repel the insects vector of disease or kill invading pathogens. They are so powerful that we use them to repel insect, fungi and bacteria.

Insect repellent- pine resin and citronella from lemon grass.

Antibacterial compounds including antibiotics- EG: phenols - antiseptic made in different plants, lysosome - containing enzymes that break dawn the bacterial cell wall

general toxins- some plans make chemicals that can break dawn to form cyanida compounds when the plant cell is attacked

Question 87

C12) what are the barriers that the body has to stop entry of pathogens

Answer 87

The skin covers the body and prevents pathogens from entering. It has skin flora of healthy microorganisms outcompete pathogens on the surface of the skin. skin produces sebum, an oily substance that inhibits the growth of pathogens

many of the body’s tracts are lined with mucous membranes that secrete mucus trapping microorganisms and contains lysozymes which destroys cell walls. it also contains phagocytes that remove remaining pathogens.

lysozymes in tears and urine and stomach also prevent pathogens getting into the body

Question 88

c12) How does expulsive reflexes defend the body

Answer 88

coughs and sneezes ejects pathogen loaded mucus from the gases exchange system

vomiting and diarrhoea expels the contents of the gut along with any pathogens

Question 89

C12)What happens when the blood clots and wounds are repaired

Answer 89

As the skin is breached, pathogens can enter the body.

Blood clots rapidly to seal the wound, when platelets come in contact with collagen in the skin or the walls of the damaged blood vessel, they adhere and begin secreting several substances

The clock dries out forming a hard tough scab to keep pathogens out. This is the first stage of window repair.

Epidermal cells below the scab start to grow ceiling the wound permanently,Damaged blood vessels regrow

Celulose fibres on deposited to give the new tissue strength.

Once the new epidermis reaches normal thickness the scab falls off

Question 90

C12) what are the substances secreted to help blood clot and wounds repair

Answer 90

Thromboplastin, an enzyme that triggers a cascade of reactions resulting in the formation of a blood clot

Serotonin, which makes the smooth-muscle in the walls of the blood vessels contract, so they narrow and reduce the supply of blood to the area

Question 91

C12) what are inflammatory responses

Answer 91

Is a localised response to pathogens resulting in inflammation at the side of the wound.

Inflammation is characterised by pain, heat, redness and swelling of the tissue

Infections that are widespread can cause an inflammatory response of a whole body rash

Question 92

C12) what are mast cells

Answer 92

They are activated in damaged tissue and release chemicals called histamines and cytokines

Question 93

C12) what are histamines

Answer 93

Histones make blood vessels dilate, Causing localised heat and redness. The rising temperature helps prevent pathogens reproducing

Makes blood vessel walls more leaky so blood plasma is forced out, once forced out of the blood it is known as tissue fluid. Tissue fluid causes swelling and pain

Question 94

C12) what are cytokines

Answer 94

Cytokines attract the white blood cells (phagocyte) to the site. They dispose of pathogens by phagocytosis

Question 95

C12) what are the two parts of the non-specific defences

Answer 95

Or adaptations to prevent pathogens growingI want to destroy them

Fever

Phagocytosis

Question 96

C12) How does the fever get rid of a pathogen

Answer 96

Normal body temperature is around 37°C and is maintained by the hypothalamus in your brain

When a pathogen invade your body, Cytokines stimulate your hypothalamus to reset the thermostat and your temperature goes up, useful adaptations because:

Most pathogens reproduce best at below 37°C. Higher temperatures inhibit pathogen reproduction

The specific immune system works faster at higher temperatures

Question 97

C12) what is phagocytosis

Answer 97

Phagocytes are specialised white cells that engulf and destroy pathogens

Two types of phagocytes - neutrophils and macrophages

Pus in a spot, cut or wound consisting of dead neutrophils and pathogens

Question 98

C12) what are the stages of phagocytosis in a neutrophil

Answer 98

Pathogen produce chemicals that attract phagocytes

Phagocytes recognise non-human proteins on the pathogen. This is a response not to a specific type of pathogen but simply a cell or organism that is non-self

The phagocyte engulfs the pathogen and encloses it in a vacuole called a phagosome

The phagosome combines with lysosomes to form a phagolysosome

Enzymes from the lysosome digestion and destroy the pathogen

Neutrophils Takes 10 minutes to undergo phagocytosis

Question 99

C12) what are the stages of phagocytosis in a macrophages

Answer 99

Pathogen produce chemicals that attract phagocytes

Phagocytes recognise non-human proteins on the pathogen. This is a response not to a specific type of pathogen but simply a cell or organism that is non-self

The Phagocytes engulfs the pathogen and encloses it in a vacuole called a phagosome

The phagosome combines with lysosomes to form a phagolysosome

Enzymes from the lysosome Digest and destroy the pathogen

macrophages combine antigens from the pathogen surface membrane with special glycoproteins in the cytoplasm called major histocompatibility complex

The major histocompatibility complex moves the pathogen antigens to the macrophages own surface membrane becoming an antigen presenting cell

This antigens stimulate the specific immune system

Question 100

C12) what are cytokines in terms of phagocytosis

Answer 100

Phagocytes that have engulfed a pathogen produce cytokines

Cytokines act as cell signalling molecules, informing other phagocytes that the body is under attack and stimulate them to move to the sight of infection or inflammation

Cytokines can also increase body temperature and stimulate the specific immune system

Question 101

C12) What are opsonins

Answer 101

Chemicals that bind to pathogens and tag them so they can be easily recognised by phagocytes

Phagocytes have receptors on the cell membrane to find common opsonins and the phagocyte then engulfs the pathogen

Question 102

c12) what are antigens

Answer 102

how the body recognise the different between self antigen on your own cells and non-self antigens of the pathogens

antigens trigger an immune response with antibodies

Question 103

C12) what is the specific immune system

Answer 103

is slower than the non-specific responses but has immune memory cells meaning it reacts quickly to a second invasion by the same pathogen

Question 104

C12) what is the structure of Antibodies

Answer 104

y shaped glycoproteins called immunoglobulins

binds to specific antigens on the pathogen which had triggered the immune response. millions of antibodies and a specific antibody for each antigen

made of 2 identical long polypeptide chains called the heavy chains and 2 shorter identical chains called the light chains

chains are held together by disulfide bridges and there are also disulfide bridges between the polypeptide chains

the binding site of antibody to the antigen is an are of 110 amino acids on both the heavy and light chains is known as the variable site. it is different for each antibody and gives the antibody its specificity.
the rest of the antibody is always the same known as the constant region

the binding of a antibody to a antigen is called antigen-antibody complex

hinge region of the antibody provides flexibility, allowing it to bind 2 antigens at its antigen-binding sites

Question 105

C12) How do you antibodies defend the body

Answer 105

The antibody of the antigen-antibody complex acts as an option so the complex is easily engulfed and digested by phagocytes

Most pathogens can no longer effectively invade the host cell once they are part of a antigen-antibody complex

Antibodies act as agglutinins causing pathogen carrying antigen-antibody complexes to clump together. This helps prevent them spreading throughout the body and making it easier for phagocytes to engulf a number of pathogens at the same time

Antibodies act as antitoxins, binding to the toxins produced by pathogens and making them harmless

Question 106

C12) what are the lymphocytes involved in the specific immune system and where are they made

Answer 106

B lymphocytes matured in the bone marrow

T lymphocytes matured in the Thymus gland

Question 107

C12) what are the main types of T lymphocytes

Answer 107

T-helper cells

T killer cells

T memory cells

T regulator cells

Question 108

C12) what is the importance of T helper cells

Answer 108

They have CD4 receptors on the cell surface membrane which binds to the surface antigen is on antigen-presenting cells

They produce interleukins which are a type of cytokine which stimulate the activity of B cells therefore increasing antibody production, stimulates production of other types of T cells and attracts and stimulate macrophages to ingest pathogens with antigen-antibody complex

Question 109

C12) what is the importance of T killer cells

Answer 109

Destroy the pathogen carrying the antigen

Produce a chemical called perforin which kills the pathogen by making holes in the cell membrane so it is freely permeable

Question 110

C12) what is the importance of T memory cells

Answer 110

Lives for a long time and are part of the immunological memory.

If they meet an antigen a second time, they divide rapidly to form a huge number of clones of T killer cells that destroyed the pathogen

Question 111

C12) what is the importance of T regulatory cells

Answer 111

Cells suppress the immune system, acting to control and regulate it

They stop the immune response once a pathogen has been eliminated and make sure the body recognises self antigens and does not set up an autoimmune response

Interleukins are important in this control

Question 112

C12) what are the different types of B lymphocytes

Answer 112

Plasma cells

B effector cells

B memory cells

Question 113

C12) what is the importance of B plasma cells

Answer 113

Produce antibodies to a particular antigen and releases them into the circulation

Active Plasma cells only lives for a few days but produces around 2000 antibodies per second while it is alive and active

Question 114

C12) what is the importance of B effector cell

Answer 114

Divide to form the plasma cell clones

Question 115

C12) what is the importance of B memory cell

Answer 115

Lives for a very long time and provides The immunological memory

Program to remember a specific antigen and enable the body to make a rapid response when a pathogen carrying that antigen is encountered again

Question 116

C12) what is cell mediated immunity

Answer 116

T lymphocytes respond to the cells of an organism that has been changed in some way, by a viral infection, by antigen processing or by mutation and two cells from transplanted tissue. The cell mediated response is particularly important against viruses and early cancer

Question 117

C12) what are the stages of cell mediated immunity

Answer 117

1) In the non-specific defence system, macrophages engulf and digest pathogens in phagocytosis. They process the antigens from the surface of the pathogen to form antigen-presenting cells
2) The receptors of some of the T-helper cells fit the antigens. These T-helper cells become activated and produce interleukins which stimulate more T cells to divide rapidly by mitosis. They form clones of identical activated T-helper cells that all carry the right antigen to bind to a particular pathogen
3) The cloned T cells may:

Develop into T memory cells, which give a rapid responseIf this pathogen invade the body again

Produce interleukins that stimulate phagocytosis

Produce interleukins that stimulate b cells to divide

Stimulate the development of a clone of T killer cells that are specific for the Presented antigen and then destroy infected cells

Question 118

C12) what is humoural immunity

Answer 118

The body responds to antigens found outside the cell for example in bacteria and fungi and to antigen-presenting cells.

Produces antibodies that are soluble in blood and tissue fluid and are not attached to cells

B lymphocytes have antibodies on their cell surface membrane and there are millions of different types of B lymphocytes, each with different antibodies.

When a pathogen enters the body it will carry specific antigens or produced toxins that act as antigens. B-cell with the complimentary antibody will bind to the antigens on the pathogen or to the free antigens. The B-cell engulfs and processes the antigens to become an antigen presenting cell

Question 119

C12) what are the stages of humeral immunity

Answer 119

1) activated T-helper cells bind to the B-cell antigen-presenting cell. This is clonal selection –the point at which the B-cell with the correct anti-body to overcome a particular antigen is selected for cloning
2) interleukins produced by the activated T-helper cells activate the B cells
3) activated B cells divide by mitosis to give clone of plasma cells and B memory cells –clonal expansion
4) Clone plasma cells produce antibodies that fight the antigens on the surface of the pathogen, bind to the antigens and disable them or act as opsonins or agglutinins. the primary response and can take days or weeks to become fully effective against a pathogen
5) Some cloned B cells develop into the memory cells. If the body is infected by the same pathogen again the B memory cells divide rapidly to form plasma cell clones. They produce the right antibodies and wipe out the pathogen is very quickly, before it can cause the symptoms of disease- secondary immunity response

Question 120

C12)What is autoimmune disease

Answer 120

Sometimes the main system stops recognising self cells and start attacking healthy body tissue

Appears to be a genetic tendency in some families, sometimes the Muinn system responds abnormally to mild pathogen is all normal body microorganisms and in some cases the T regulator so do not work effectively

Can cause chronic inflammation or the complete breakdown and destruction of healthy tissue. Immunosuppressant drugs, Prevents the immune system working can be used as treatment

Question 121

C12)What is natural active immunity

Answer 121

When your immune system is activated and antibodies are formed which result in the Destruction of the antigen

The main system produces TNB memory cells so if you meet a pathogen for a second time, your immune system recognises the antigen and can immediately destroy the pathogen

Known as active because the body has its self acted to produce antibodies and or memory cells

Question 122

C12) what is natural passive immunity

Answer 122

The immune system of a newborn baby is not mature and it cannot make antibodies for the first couple of months

Some antibodies cross the placenta from the mother to her fetus while the baby is in the uterus, so it has some immunity to diseases at birth

The first milk a mammalian mother makes is called Colostrum which is very high in antibodies. For the first few days breastfed babies will have the same Antibody protection against diseases as the mother

Lasts until the immune system of the baby begins to make its own antibodies. The antibodies the baby receives from the mother are likely to be relative to pathogen is in its environment

Question 123

C12) what is artificial passive immunity

Answer 123

For certain potentially fatal diseases, antibodies are formed in one individual extracted and then injected into the bloodstream of another individual

Temporary immunity-it doesn’t last long but can be life-saving

For example tetanus And rabies can be treated like this

Question 123

C12) what is artificial active immunity

Answer 123

Immune system of the body is stimulated to make its own antibodies to a safe form of an antigen (a vaccine), which is injected into the bloodstream (vaccination)

The antigen is not usually the normal live pathogen

May last a year, a few years or a lifetime

Sometimes boosters are needed to increase the time you are immune to the disease

Question 123

C12)What are the stages of artificial active immunity

Answer 123

1) The pathogen is made safe in a number of ways so that the antigen are intact but there is no risk of infection
2) Small amounts of the safe antigen known as a vaccine are injected into the blood
3) The primary immune response is triggered by the foreign antigens and your body produces antibodies and memory cells as if you were infected with a live pathogen
4) If you came into contact with a live pathogen, the secondary immune response is triggered and you destroy the pathogen rapidly before you suffer symptoms of the disease

Question 123

C12) what might vaccines contain

Answer 123

Killed or inactivated bacteria and virus

Attenuated strains of life bacteria or virus for example, rubella, BCG against TB, polio

Toxin molecules have been altered and detoxified: tetanus, diphtheria

Isolated antigens extracted from the pathogen

Genetically engineered antigens, the hepatitis B vaccine

Question 123

C12) what is a pandemic and an epidermic

Answer 123

An epidermic is when a communicable disease spreads rapidly to a lot of people at a local or national level

An epidermic is when the same disease spreads rapidly across a number of continents and countries

Question 123

C12) what are some communicable diseases that cause problems at a global level but cannot be prevented by vaccinations

Answer 123

Malaria- Plasmodium, The parasite that causes malaria. Very invasive-it Spends time inside the Erythrocyte so it is protected by self antigens from the Immune system and within an infected individual it’s antigens reshuffle

HIV - Causes AIDS- it enters the microcrophages and T-helper cells, so it has disabled the immune system itself

Question 125

C12) how was penicillin sourced

Answer 125

First widely used, effective, safe antibiotic capable of curing bacterial diseases

From a mould, famously discovered by Alexander Fleming

Fleming so what the mould did to his bacteria but could not expect enough to test its potential

Question 127

C12) how are medication sourced

Answer 127

From a wide range of sources

Scientist designed drugs using complex computer programs. They build three-dimensional models of key molecules in the body and of pathogens and antigen systems allowing models of potential drugs to be built up which are targeting the particular areas of the pathogen

Computers are also used to search through enormous libraries of chemicals to isolate any with potential useful action against a specific group of features of a pathogen or mutated cells in a cancer

Analysis of genomes of pathogens and GenesWhich have been linked to cancers enable Scientists to attack vulnerabilities

Many drugs most commonly used in medicine are still derived from or based on Bioactive compounds discovered in plants, micro organisms or other forms of life

Deforestation of rainforest might lead to extinction of life-saving plants, animals and microorganisms which can give us key life-saving drugs

Question 128

C12) What is pharmacogenetics

Answer 128

Personalised medicine- a combination of drugs that work with your individual combinations of genetic and diseases

The science of interweaving knowledge of drug actions with personal genetic material

In the future this type of treatment, where the clinicians look at the genome of the patient and the genome of the invading pathogen before deciding how to treat them

Question 129

C12) what is synthetic biology

Answer 129

The technique of genetic engineering, can develop populations of bacteria to produce much- needed drugs that would otherwise be too rare, too expensive or just not available

Nanotechnology, where tiny, non-natural particles are used for biological purposes

Question 130

C12) What is selective toxicity

Answer 130

Antibiotics interfere with the metabolism of the bacteria without affecting the metabolism of human cells

Question 131

C12) how has antibiotic resistance occurred

Answer 131

Antibiotics work because a bacterium has a binding site for the drug and a metabolic pathway that is affected by the drug

A random mutation during bacterial reproduction produces a bacterium that is not affected by antibiotics

This bacteria is best fitted to survive and reproduce passing on the antibiotic resistant mutation to the daughter cells

Bacteria reproduce very rapidly, so a mutation occurs it does not take long to grow a big population of antibiotic resistant bacteria

Question 132

C12) how can antibiotic resistance be reduced

Answer 132

Minimising the use of antibiotics and insuring that every course of antibiotics is completed to reduce the risk of resistant individual surviving and developing into a resistance strain population

Good hygiene in hospitals, care homes and in general-this has a major impact on the spread of infections, including antibiotic resistant strains

Question 133

C11) what is the meaning of biodiversity

Answer 133

The variety of living organisms present in an area.

Include plants, animals, fungi and other living things

Question 134

C11) what is the importance of biodiversity

Answer 134

Biodiversity is essential in maintaining a balanced ecosystem for all organisms

All species are interconnected – they depend on one another

In regions of reduced biodiversity, connections may not be present which eventually harms all species in the ecosystem

We rely on balanced ecosystems as they provide us with the food, oxygen and other materials we need to survive

Human activities can lead to a reduction in biodiversity

Question 135

C11) what is biodiversity like around the world

Answer 135

Tropical, moist regions have the most biodiversity

The U.K.’s temperate climate has less diversity

Very cold areas such as the Arctic or very dry areas such as deserts have the least biodiversity

Generally the closer the region is to the equator the greater the biodiversity

Question 136

C11)What is the importance of measuring biodiversity

Answer 136

Important role in conservation

It informs scientists of the species that are present therefore providing a baseline for the level of diversity in an area

From this information the effects of any changes to an environment can be measured

These may include the effects of human activity, disease or climate change

Question 137

C11) what are the different levels that biodiversity can be studied at

Answer 137

Habitat biodiversity

Species diversity

Genetic diversity

Question 138

C11) what is the importance of habitat biodiversity

Answer 138

Refers to the number of different habitats found within an area

Each habitat can support a number of different species, therefore the greater the habitat biodiversity the greater the species diversity within that area

The UK has A large number of habitat types therefore it has a large habitat biodiversity, while Antarctica covered almost entirely in an ice sheet has a very low habitat biodiversity and very few species

The countryside is habitat rich, perhaps with a river, woodland, hedgerows and wild grassland, will be more species rich than farmed countryside.

Question 139

C11) what are the two different components of species biodiversity

Answer 139

Species richness-the number of different species living in a particular area

Species evenness-a comparison of the number of individuals of each species living in A community

Question 140

C11) what is the meaning of genetic biodiversity

Answer 140

Variety of genes that make up the species

Many of these genes are the same for all individuals within a species. However for many genes, different versions exist leading to genetic biodiversity within a species

Genetic biodiversity within a species can lead to quite different characteristics being exhibited

Greater genetic biodiversity within a species allow for better adaptations to a changing environment and is more likely to result in individuals who are resistant to disease

Question 141

C11) what is sampling

Answer 141

Means taking measurements of a limited number of individual organisms present in a particular area

Sampling can be used to estimate the number of organisms in an area without counting them. The number of individuals of an species present in an area is known as the abundance of organism.

Sampling can be used to measure particular characteristics of an organism

After measuring a sample, you can use the results of the sample to make Estimation is about the number of organisms or characteristics throughout the habitat

Two types of sampling-random and non-random

Question 142

C11)What is random sampling

Answer 142

Selecting individuals by chance. Each individual in the population has an equal likelihood of selection

To decide which organism to study random number Computers can be used. You have no involvement in deciding which organism to investigate.

For example:

1) mark out a grid on the area using two tape measures laid at right angles
2) use random number generator to determine the x-coordinate and the Y coordinate on your grid
3) take a sample add each of the coordinates generated

Question 143

C11) what are the three different techniques of non-random sampling

Answer 143

Opportunistic

Stratified

Systematic

Question 144

C11) what is the opportunistic method of non-random sampling

Answer 144

Weakest form of sampling as it may not be representative of the population. Uses organisms that are conveniently available

Question 145

C11) what is the Stratified method of non-random sampling

Answer 145

Some populations can be divided into a number of strata (subgroups) based on particular characteristics

The population might be separated into male and female. A random sample is then taken from each of these strata populations for its size

Question 146

C11) what is the systematic method of non-random sampling

Answer 146

Different areas within an overall habitat are identified, which are then sampled separately

Systematic sampling is often carried out using a line or a belt transect

A line transect involves marking a line along the ground between two poles and taking samples at specific points, can include describing all organisms touching the line or a distance from the line

A belt transect provides more information–Two parallel lines are marked and samples are taken on the area between the two lines

Question 147

C11) How can sampling bias affect reliability

Answer 147

The selection process may be biased. This may be by accident or may occur deliberately. The effects of sampling bias can be reduced to using random sampling, where human involvement in choosing the samples removed

Question 148

C11) How can chance affect reliability

Answer 148

Organisms selected may, By chance not be representative of the whole population. Chance can never be completely removed from the process but its effects can be minimised by using a large sample size.

The greater the number of individuals studied, the lower the probability that chance will influence the result. Larger the sample size the more reliable the result

Question 149

C11) what are the different techniques used for sampling animals

Answer 149

All living organisms must be handled carefully and for a short time period as possible. As soon as any sample animals have been identified, counted and measured if required they must be released back into the habitat at the point they were collected

Sweep nets are used to catch insects in areas of long grass

Pitfall traps are used to catch small, crawling invertebrates such as Beatles. A whole is dug in the ground which insects fall into , deep enough that they don’t escape and covered with the roof structure propped above so that the trap does not fill with rainwater

Tree beating is used to take samples of invertebrates living in a tree or bush. A large white cloth is stretched out under the tree, the tree is shaken or beaten to dislodge the invertebrates. The animals will fall onto the sheet where they are collected and studied

Question 150

C11) how do we sample plants

Answer 150

Using a quadrat, which can also be used to pinpoint an area in which the sample of plant can be collected

Quadrats can also be used to sample slow-moving animals such as mussels

To connect the most valid representative sample of an area, contracts should be used following a random sampling technique.
To study how the presents and distribution of organisms across an area of land varies the quad rats can be placed systematically along a line transect

Question 151

C11) what are the two types of Quadrats

Answer 151

Point quadrat- consists of a wooden frame containing horizontal bar. At set intervals along the bar, long points can be pushed through the wall to reach the ground. Each species of plant point touches is recorded

Frame quadrat- consists of a square frame divided into a grid of the equal sections. The type and number of species within each section of the quadrant is recorded

Question 152

C11) how to collect data on species richness

Answer 152

By using a combination of techniques to try to identify all the species present in the habitat
A list should be compiled of each species identified. The total number of species can then be calculated.

To enable scientists to accurately identify organisms, identification keys are often used. They may contain images to identify the organisms, or a series of questions which classify an organism into a particular species based on the presence of a number of identifying characteristics

Question 153

C11) what are the three main ways of using a frame quadrat to sample the population of living plants in a habitat

Answer 153

Density- if individual large plants can be seen clearly clearly count the number of them in one by one squared quadrat. This will give you the density per square metre. An absolute measure, not an estimate

Frequency- used to where individual members of species are hard to count. Using the small grids within a quadrat count the number of squares a particular species is present in. If it is 100 square quadrant, each square represents 1%. If it is a 25 squared quadrat, Each square represents 4% of the study area

Percentage cover - Use for speed as loads of data can be collected quickly. Useful when particular species is abundant or difficult to count an estimate by eye of the area within a quadrat that a particular plant species cover

Question 154

C11) how do scientists estimate animal population sizes

Answer 154

Animals are constantly moving through a habitat and others may be hiding it can be difficult to accurately determine their population size

Technique known as capture Mark release recapture is often used to estimate a population size

Involves capturing as many individuals of a species in an area as possible, the organisms are marked and then released back into the community. Time is allowed for the organism to redistribute themselves throughout the habitat before another sample of animals is collected. By comparing the number of marked individuals with the number of non-marked individualsScientists can estimate population size. The greater the number of marked individuals recaptured the smaller the population

Question 155

C11) what is the technique of capture mark recapture release

Answer 155

Involves capturing as many individuals of a species in an area as possible, the organisms are marked and then released back into the community. Time is allowed for the organism to redistribute themselves throughout the habitat before another sample of animals is collected.

By comparing the number of marked individuals with the number of non-marked individuals Scientists can estimate population size. The greater the number of marked individuals recaptured the smaller the population

Question 156

C11) what are the Ways to measure abiotic factors

Answer 156

Nonliving conditions in a habitat have a direct effect on the living organisms that reside there. Amount of light and water availability.

Enables them to draw conclusions about the organisms present and the conditions they need to survive, scientist normally measure these conditions at every measuring point

Question 157

C11)What are the different ways of measuring common abiotic factors

Answer 157

Wind speed- anemometer

Light intensity-light meter

Relative humidity- humidity sensor

PH- pH probe

Temperature- temperature probe

Oxygen content in water- dissolved oxygen probe

Question 158

C11)What are the Advantages of measuring abiotic factors quickly and accurately using a range of sensors

Answer 158

Rapid changes can be detected

Human error in taking a reading is reduced

A high degree of precision can often be achieved

Data can be stored and tracked on a computer

Question 159

C11) What is the Simpsons index of diversity

Answer 159

Takes into account both species richness and species evenness

Scientists normally have to estimate population size using a variety of sampling techniques such as using a quadrat to estimate the population of plant species in an area

Simpsons index of diversity always results in a value between zero and one, with zero represents no diversity and the value of one represents infinite diversity. The higher the value of Simpsons index of diversity the more diverse the habitat

Question 160

C11) what are the characteristics of low biodiversity

Answer 160

Relatively few successful species

Stressful and extreme with relatively few ecological niches for an environment

Relatively few species live in the habitat, often with very specific adaptations for the environment

Relatively simple food web

Major effects on the ecosystem as a whole

Question 161

C11) what are the characteristics of high biodiversity

Answer 161

A large number of successful species

Relatively benign/not stressful, with more ecological niches

Many species live in the habitat, often with few specific adaptations to the environment

A complex food webs

Often relatively small effect on the ecosystem as a whole

Question 162

C11) what is the importance of maintaining some low biodiversity environments

Answer 162

Some organisms that are present in habitat can be highly adapted to the extreme environments of the habitat

These organisms may not survive elsewhere therefore it is important to conserve some habitats with low biodiversity in order to conserve rare species

Question 163

C11) what is the importance of genetic biodiversity

Answer 163

Within a species, individuals have very little variation in their DNA

All members of the species share the same genes. They may have different versions of some of these genes called alleles

The different values among individuals of a species creates genetic biodiversity within the species. The more alleles present in a population, the more genetic biodiversity in the population

Species that contain greater genetic biodiversity are likely to be able to adapt to changes to the environment and are less likely to become extinct Because there are likely to be some organisms within the population that carry an advantages alleles

Question 164

C11) what are the ways of increasing genetic biodiversity

Answer 164

The number of possible alleles in a population must also increase

Mutations in the DNA of an organism creating a new allele

Interbreeding between different populations within a species. When an individual migrate from one population breeds with a member of another population, alleles are transferred between the two populations-gene flow

Question 165

C11)What are different ways genetic biodiversity can decrease

Answer 165

The number of possible alleles in a population must also decrease

Selective breeding, where only a few individuals within a population are selected for their advantages characteristics and bread.

Captive breeding programs in zoos and conservation centres, where only a small number of captive individuals of a species are available for breeding

Artificial cloning

Natural selection- species will evolve to contain primarily the alleles which code for advantages characteristics, overtime values coding for less advantages characteristics will be lost from the population

Genetic bottlenecking - few individuals within a population survive an event or change, reducing the gene pool. Only the values of the surviving members of the population are available to be passed on to offspring

Founders effect -what a small number of individuals create a new colony-geographically isolated from the original. The gene pool of the new population is smaller

Genetic drift –the random nature of alleles being passed on from parents to their offspring, the frequency of occurrence of an allele will change. More pronounced in population with a low genetic biodiversity

Question 166

C11) what are polymorphic genes and how are they used to measure genetic biodiversity

Answer 166

They have more than one allele

Most genes are monomorphic- A single allele exist for this gene. Insures that the basic structure of individuals within a species remain constant

The greater the proportion of polymorphic gene loci The greater the genetic biodiversity within the species

Question 167

C11) what is the formula for proportion of polymorphic gene Loci

Answer 167

Number of polymorphic gene loci
———————————————————
Total number of Loci

The locus of a gene refers to the position of the gene on a chromosome

Question 168

C11) What are the main problems occurring that causes disruptions to the ecology of many areas

Answer 168

Deforestation- permanent removal of large area of forest to provide wood for building a few and to create space for roads

Agriculture – an increasing amount of land has to be formed in order to feed the growing population resulting in large amounts of land being cleared and in many tasted planted with a single crop

Climate change-evidence that the release of carbon dioxide and other pollutants into the atmosphere is increasing global temperature

Question 169

C11) how does Deforestation affect biodiversity

Answer 169

Directly reduces the number of trees present in an area

If only a specific type of tree is failed, the species diversity is reduced but less usable trees may be left intact

It reduces the number of animal species present in an area as it destroys their habitat, including their food source and home. This reduces the number of other animal species that are present by reducing or removing their food sauce

Animals are forced to migrate to other areas to ensure their survival resulting in the biodiversity of neighbouring areas increase

Question 170

C11)How does agriculture affect biodiversity

Answer 170

Farmers will only grow a few different species of crop plants, or readjust a few species of animals. Farmers often select the species spread on characteristics to give a high yield. The selection of only a few species greatly reduces the biodiversity in the area

In order to be economically viable, once the farmers have selected the desired species, a number of techniques are used to produce as many of the desired species as possible, maximising food production

Question 171

C11) what are the different techniques used by farmers to maximise food production which lead to reduction in biodiversity

Answer 171

Deforestation –to increase the area of land available for growing crops or rearing animals

Removal of hedgerows - as a result of mechanisation, farmers remove hedge Rose to enable them to use large machinery to help them plant, fertilise and harvest crops. Also frees up extra land for crop growing. Reduces the number of plant species present in an area and destroys the habitat of animals and invertebrate

Use of chemicals such as pesticides and herbicides - are used to kill pests that can eat the cropper live on the animal, reduce the species diversity directly as it destroys the pest species and indirectly by destroying the food source of other organisms

Herbicides are used to kill weeds. The weed is another plant growing in an area where it is not wanted. Weeds are destroyed as they compete with the cultivated plant for light minerals and water. Thereby plant diversity is reduced directly and animal diversity may also be reduced by the removal of an important food source

Mono culture - farm specialise in the production of only one crop, with many acres of land being used for the growth of one species leading to the lowering of biodiversity as only one species of plant is present. As relatively few animal species will be supported by only one type of plants

Question 172

C11) What are the key findings of the intergovernmental Panel on climate change

Answer 172

The warming trend over the last 50 years is nearly twice that of the previous 100 years

Since 1961, the average temperature of the global ocean down to depth of 3 km has increased. The ocean has been absorbing more than 80% of the heat added to climate system causing seawater to expand and contributing to sea level rise

Average Arctic temperatures have increased At almost twice the global average rate in the past hundred years

Mountain glaciers and snow cover have declined on average in both hemispheres. Widespread declines in glaciers and an ice caps have contributed to sea level rise

Long-term upward trend to the amount of precipitation has been observed over many Regions

Question 173

C11) how does global warming affect biodiversity

Answer 173

The melting of the polar ice caps can lead to the extinction of the few plants and animal species living in these regions. Some species of animals present in the Arctic on migrating further and further north to find favourable conditions. Increasing global temperatures would allow temperate plants and animal species to live further north than currently

Increasing Sea levels from melting ice caps and the thermal expansion of oceans could flood low-lying land, reducing the available territorial habitat. Salt water would flow further up river reducing the habitats of freshwater plants and animals living in the river and surrounding areas

Higher temperatures and less Rainfall would result in some plant species failing to survive leading to Drought resistant species becoming more dominant. Loss of Non-drought resistant species of plants would lead to the loss of some animal species depending on them as food

Question 174

C11) what are some aesthetic reasons to maintain biodiversity

Answer 174

The presence of different animals and plants in our environment in riches our lives

The natural world provides inspiration for people such as musicians and writers, who intern provide pleasure for many other people

Studies have shown that patient recovers more rapidly from stress and injury when they are supported by plants and a relatively neutral environment

Question 175

C11) what are the economic reasons to maintain biodiversity in an ecosystem

Answer 175

Soil erosion and desertification may occur as a result of deforestation. These reduce a country’s ability to grow crops and feed its people, which can lead to resources an economic dependency on other nations

Large-scale habitats and biodiversity Loss means that species with potential economic importance may become extinct before they are even discovered, chemically or Medicine really useful

High biodiversity provides protection against abiotic stress and disease. When biodiversity is not maintained a change in conditions or a disease can destroy entire crops

Areas rich in biodiversity provides a pleasure, attractive environment that people can enjoy. Highly biodiversity areas can promote tourism in the region which is associated with economic advantage

The greater the diversity in an ecosystem, the greater the potential for the manufacture of different products in the future which may be beneficial to humans

Question 176

C11)What are the ecological reasons to maintain biodiversity

Answer 176

All organisms are interdependent on others for their survival. The removal of one species may have a significant effect on others

Some species play a key role in maintaining the structure of an ecological Community. These are known as keystone species. They have a disproportionately large effect on the environment relative to the abundance. They affect many other organisms in an ecosystem and help to determine the species richness and evenness in the community. If a keystone species is removed the habitat is drastically changed. All other species are affected and some may disappear altogether.Essential to protect keystone species to maintain biodiversity

Question 177

C11) how has human activity positively affected biodiversity

Answer 177

In many countries the natural habitat is created by human intervention andThe management of land

This enables rare species to survive

Question 178

C11) what is conservation

Answer 178

The name given to the preservation and careful management of the environment and other natural resources

By conserving the natural habitat in an area, organisms chances of survival are maintained allowing them to reproduce

Consequently species and genetic diversity can be safeguarded

Question 179

C11) what are the two main categories of conservation

Answer 179

In situ conservation-within the natural habitat

Ex situ conservation-out of the natural habitat

Question 180

C11) what are the classifications of species are put into for the purpose of conservation

Answer 180

Extinct - no organism of the species exist anywhere in the world

Extinct in the world –organisms of the species only exist in captivity

Endangered- a species that is in danger of extinction

Vulnerable- a species that is considered likely to become endangered in the future

Nonthreatened and categories of least concern follow below

Question 181

C11) what is sustainable development

Answer 181

Many conservation techniques focus on increasing the number of organisms from species that are classified as endangered

Scientists are promoted to practice sustainable development- economic development that meets the needs of people today, without limiting the ability of future generations to meet their needs

Question 182

C11)What are the advantages of in situ conservation

Answer 182

Takes place inside an organisms natural habitat

Maintains not only the genetic diversity of species but also the evolutionary adaptations that enable a species to adapt continuously to changing environmental conditions such as a pest population or climate

By allowing the endangered species to interact with other species, It preserves the interdependent relationship present in a habitat, therefore interlinked species may be preserved

In situ conservation is generally cheaper than ex situ conservation

Marine (saltwater), aquatic (freshwater) and territorial natural reserves are examples of areas specifically designed for the conservation of wildlife

Question 183

C11) what are active management techniques used on a wildlife reserve

Answer 183

Control grazing - only allowing livestock to graze a particular area of land for a certain period of time to allow species Time to recover or keeping a controlled number of animals in a habitat to maintain it

Controlling poaching - this increase creating defences to prevent access, issuing fines or more drastic steps such as the removal of rhino horns

Feeding animals – this technique can help to ensure more organisms survive to reproductive age

Reintroduction of species- adding species to areas that have become locally extinct, or whose numbers have declined significantly

Calling or removing invasive species – aninvasive species is an organism that is not native to an area and have negative effects on the economy, environment or health. These organisms compete with native species for resources

Question 184

C11) what is the importance of marine conservation zones

Answer 184

Marine reserves are vital in preserving species - rich area such as coral reefs which are being devastated by non-sustainable fishing methods

Purpose of marine reserves is not to prevent fishermen from visiting the entire area but to create areas of refuge within which populations can build up and re-populate adjacent areas.

Large areas of sea are required for marine reserves as the target species often move long distances or breed in geographically different areas

Question 185

C11) want a Botanic Gardens like for ex situ conservation

Answer 185

Plant species can grow successfully in botanic Gardens. Hate the species are actively managed to provide them with the best resources to grow, such as the provision of soil nutrients, sufficient water in and the removal or prevention of pests

The majority of species are not conserved. Many wild relative of selectively bred crop species are underrepresented amongst conserve species. These wild species are a potential source of genes, with resistance to disease, pests and parasites

Question 186

C11) how are seed banks a good place for ex situ conservation

Answer 186

A seed bank is an example of a gene bank-a store of genetic material

Seeds of carefully stored so that new plants can be grown in the future. They are dried and stored at temperatures of -20°C to maintain their viability by slowing down the rate at which they lose their ability to germinate. All temperatures seeds and some tropical seeds can be stored this way being viable for centuries providing a backup against extinction of wild plants

The doomsday vault in Norway door seeds in the permafrost and already holds around 800,000 species, eventually having 3 million different types of seeds and aims to provide a back up against the extinction of plants in the wild by storing seeds for future reintroduction and research for breeding and for genetic engineering in the future

Seed banks don’t work for all plants, some seeds die when dried and frozen and the seeds of the most tropical rainforest trees fall into this category

Question 187

C11)How is captive breeding programs and example of ex situ conservation

Answer 187

Captive breeding programs produce offspring of species in a human controlled environment

Often run managed by zoos and aquatic centres. Several species are now solely represented by animals in captivity newcomer scientists working on captive breeding programs aimed to create a stable, healthy population Of a species and then generally reintroduced to species back into natural habitat

Provides the animals with shelter, and abundant supply of nutritious food, an absence of predators and veterinary treatment.Suitable breeding partners or semen can be imported from other zoos if not available within the zoos own population

Question 188

C11) what is the problem with captive breeding programs

Answer 188

Maintaining genetic diversity within a captive breeding population can be difficult.

Only a small number of breeding partners are available, problems related to interbreeding can occur. An international catalogue is maintained, detailing genealogical data on individuals.

Mating can be arranged to ensure that genetic diversity is maximised. Techniques such as artificial insemination, embryo transfer and long-term higher genic storage of embryos allow new genetic lines to be introduced without transporting the adult to new locations and does not require animal corporation

Question 189

C11) what are the reasons that some organisms born in captivity not being able to be released

Answer 189

Diseases- there may be a loss of resistance to local diseases in captive populations. Maybe new diseases might exist in the wild to which captive animals have yet to develop resistance

Behaviour- some behaviour is innate but much has to be learned through coping or experience. In an earlier case of reintroduction a number of monkeys starved because they had no concept of having to search for food.

Genetic race- the genetic make up of captive animals can become so different from the original population that the two populations cannot interbreed

Habitat – in many cases the natural habitat must first be restored to allow captive populations to be reintroduced. If only a small habitat exists there is already as many individuals as the habitat can support already exist. This can lead to stress and tension as individuals fight for limited territory and resources such as food

Question 190

C11) What is the importance of the international union for the conservation of nature

Answer 190

Intergovernmental organisation that assist in securing agreements between nations

Once a year the International union for the conservation of nature publishes the red list detailing the current conservation status of threatened animals allowing countries to work together to conserve these species

Also involved in the establishment of the Convention on International trade in endangered species- Treaty regulates the International trade of wild plant and animal specimens and their products. As the trade in wild animals and plants crosses borders between countries the effect of regulate it requires international corporation to safeguard certain species from over exploitation

Question 191

C11) what were the agreements made at the Rio convention

National level

Answer 191

Known as the Earth Summit

The conservation of biological diversity requires countries to develop national strategies for sustainable development does ensure the maintenance of biodiversity

The United Nations framework Convention on climate change is an agreement between nations to take steps to stabilise greenhouse gas concentrations within the atmosphere

The United Nations Convention to combat desertification aims to prevent the transformation of fertile land into desert and reduce the effects of drought through programs of international corporation

Question 192

C11)What is the countryside stewardship scheme

Local level

Answer 192

Many conservation schemes are set up at more local level

Operated from 1991 to 2014, offered governmental payments to farmers and other land managers to enhance and conserve the English landscape. Its general aim was to make conservation a part on natural farming and land management practice

Scheme has been replaced by the environmental stewardship scheme

Question 193

C11)What are the specific aims of the countryside stewardship scheme

Answer 193

Sustaining the beauty and diversity of the landscape

Improving, extending and creating wildlife habitats

Restoring neglected land and conserving archaeological and historical features

Improving opportunities for countryside enjoyment