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A-level biology > AS - Unit 2 - Biodiversity and evolution > Flashcards

AS - Unit 2 - Biodiversity and evolution Flashcards

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1
Q

What is a species?

A

A group of individual organisms very similar in appearance, anatomy, physiology, biochemistry and genetics, whose members are able to interbreed freely to produce fertile offspring

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2
Q

What is a habitat?

A

The place where an organism lives

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3
Q

What is biodiversity?

A

The variety of life - the range of living organisms to be found

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4
Q

What three things do you have to consider when organising biodiversity?

A

The range of habitats in which different species live
The difference between species
Genetic variation between individuals belonging to the same species

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5
Q

What is random sampling?

A

Studying a small part of the habitat and assuming it contains a representative set of species that can be applied to the whole habitat.

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6
Q

Give 5 ways of catching animals to count and calculate biodiversity

A 
A pooter
Sweep netting
Pitfall trap
Tullgren funnel
Light trap
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7
Q

What is species richness?

A

The number of species present in a habitat

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8
Q

What is Simpson’s diversity index?

A

A formula used to measure the diversity of a habitat

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9
Q

What is species evenness?

A

The number of individuals in each species

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10
Q

What survey can be used to estimate species richness?

A

A qualitative survey

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11
Q

How can you calculate species evenness?

A

Quantitative survey

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12
Q

What is biological classification?

A

The process of sorting living things into groups. Natural classification does this by grouping things according to how closely related they are. Natural classification reflects evolutionary relationships

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13
Q

What is taxonomy?

A

The study of the principles of classification

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14
Q

What is phylogeny?

A

The study of the evolutionary relationships between organisms

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15
Q

What are protoctists?

A

They include all the organisms that don’t fit into the other four kingdoms. Many are single-celled, but some are multicellular

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16
Q

What do all prokaryotes not have?

A

No nucleus

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17
Q

What are fungi?

A

Organisms that are mostly saprophytic. They consist of a mycelium with walls made from chitin

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18
Q

What are plants?

A

Multi cellular organisms that gain their nutrition from photosynthesis

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19
Q

What are animals?

A

Heterotrophic multicellular eukaryotes

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20
Q

What are the five different kingdoms?

A 
Prokaryotes
Protoctists
Fungi
Plants
Animals
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21
Q

Give 7 characteristics of an organism which would allow it to be categorised in the prokaryotes kingdom

A

no nucleus
loop of naked DNA (not arranged in linear chromosomes)
No membrane bound organelles
Smaller ribosomes
Carry out respiration not in mitochondria, but on special membrane systems (mesosomes)
May be free-living or parasitic (some cause diseases)

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22
Q

Give 6 characteristics of an organism which would allow it to be categorised in the protoctist kingdom

A

Eukaryote
Mostly single-celled
Show a wide variety of forms
Various plant-like or animal-like features
Mostly free-living
Have autotrophic or heterotrophic nutrition - some photosynthesise, some ingest prey, some feed using extracellular enzymes, some are parasites

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23
Q

Give 5 characteristics of an organism which would allow it to be categorised in the fungi kingdom

A

Eukaryote
Have a mycelium, which consists of hyphae
Walls made of chitin
Cytoplasm that is multinucleate
Mostly free-living and saprophytic - means that they cause decay of organic matter

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24
Q

Give 5 characteristics of an organism which would allow it to be categorised in the plants kingdom

A 
Eukaryote
Multicellular
Cellulose cell wall
Produce multicellular embryos from fertilised eggs
Autotrophic nutrition
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25
Q

Give 5 characteristics of an organism which would allow it to be categorised in the animal kingdom

A 
Eukaryote
Multicellular
Heterotrophic nutrition
Fertilised eggs that develop in a ball of cells called a blastula
Usually able to move around
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26
Q

Give 4 reasons for organising species into a classification

A

For our convenience
To make the study of living things more manageable
To make it easier to identify organisms
To help us see the relationships between species

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27
Q

What are the eight taxonomic groups?

A 
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
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28
Q

What are the three domains?

A

Bacteria
Archaea
Eukaryotae

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29
Q

What three features do all members of the class Insecta have in common?

A

Three body parts
6 legs
Usually two pairs of wings

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30
Q

What two features do all members of the class Arachnida have in common?

A

Two body parts

8 legs

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31
Q

What is the binomial system?

A

It uses two names to identify each species; the genus name and the species name

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32
Q

What is a dichotomous key?

A

It uses a series of questions with two alternative answers to help you identify a specimen

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33
Q

Why does using a common name for an organism not work very well?

A

Same organism has a completely different common name in different parts of one country
Different common names are used in different countries
Translation of languages or dialects may give different names
Same common name may be used for different species in other parts of the world

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34
Q

What protein is used to compare how closely related two species are and how does it work?

A

Cytochrome c
If we compare the sequence of amino acids in samples of cytochrome c from two different species you can figure out:
If the sequences are the same, the two species must be closely related
If the sequences are different, the two species are not closely related
The more differences found between the sequences, the less closely related the two species

35
Q

What is variation?

A

The presence of variety - of differences between individuals

36
Q

What is genetic variation?

A

It is caused by differences between the genes and the combinations of genes or alleles

37
Q

What is continuous variation?

A

Variation in which there is a full range of intermediate phenotypes between two extremes

38
Q

What is discontinuous variation?

A

Variation in which there are discrete groups of phenotypes with no or very few individuals in between

39
Q

Give three examples of continuous variation

A

Height in humans
Length of leaves on an oak tree
Length of stalk on a toadstool

40
Q

Give three examples of discontinuous variation

A

Sex - mammals are either male or female; plants can be male, female or hermaphrodite
Some bacteria have flagella, but other do not
Human blood groups - A, B, AB or O

41
Q

How can the environment cause variation among a species?

A

An overfed pet will become obese

A person’s skin will tan and become darker with careful exposure to sunlight

42
Q

What is an adaptation?

A

A feature that enhances survival and long-term reproductive success

43
Q

What is a xerophyte?

A

A plant which is adapted to live in very dry conditions

44
Q

How does the process of evolution work?

A

By selecting particular adaptations to survive from one generation to the next

45
Q

Give 7 things that a well adapted organism should be able to do

A

Find enough food or photosynthesise well
Find enough water
Gather enough nutrients
Defend itself from predators and diseases
Survive the physical conditions, e.g. temperature, light and water level changes
Respond to changes in the environment
Still have enough energy left over to reproduce successfully

46
Q

How do behavioural adaptations affect an organism?

A

An organism will do specific things in order to increase its chance of survival.
e.g. when you touch an earthworm it quickly contracts and withdraws into its burrow
It has no eyes, and cant tell that you aren’t a bird about to eat it, so the rapid withdrawal is a behavioural adaptation to stop it from being eaten

47
Q

How do biochemical adaptations affect an organism?

A

A biochemical adaptation is one which ensures correct functioning of cell processes. E.g. yeast can respire anaerobically or aerobically to obtain energy, depending on how much oxygen is available in the environment. Producing the correct enzymes to respire the sugars present is a biochemical adaptation

48
Q

How do anatomical adaptations affect an organism?

A

An anatomical adaptation is any structure which enhances the survival of the organism. E.g. many bacteria have flagella that enable them to move independently.

49
Q

Give 4 ways in which xerophytes respond to a shortage of water

A

Close their stomata when little water is available so they do not wilt
Open their stomata at night, conserves water because less will be lost from the leaves at night when it is cooler and the air is more humid
Fold or roll their leaves, reduces water loss by trapping moist air in the folded leaf
Some plants open their stomata when short of water, this causes the leaves to wilt and exposes less surface area to the sun

50
Q

Give 6 examples of the anatomical adaptations taken by xerophytic plants to air their survival

A 
Shallow roots 
Long roots 
Fleshy stem or leaves 
Smaller leaves 
Waxy leaves 
Curled leaves
51
Q

What four observations did darwin make which led to his new theory?

A

Offspring appear similar to their parents
No two individuals are identical
Organisms have the ability to produce large numbers of offspring
Populations in nature tend to remain fairly stable in size

52
Q

What is natural selection?

A

The ‘selection’ by the environment of particular individuals that show certain variations. These individuals will survive to reproduce and pass on their variations to the next generation.

53
Q

What is speciation?

A

The formation of a new species

54
Q

Which 4 factors can affect natural selection?

A

Availability of suitable food - if an organism is adapted to eat the most abundant food they are more likely to survive
Predators - adapted to avoid being sen or eaten
Diseases - if they can survive disease they have an advantage
Physical and chemical factors - if an organism can adapt to extreme weather conditions they have a selective advantage

55
Q

What is a reproductive barrier?

A

A factor which prevents effective reproduction between members of the same species

56
Q

What is geographical separation?

A

Different groups of the same species living on different islands are unlikely to interbreed freely, they could be separated by the slow formation of a mountain range not allowing them to mix again

57
Q

What is geographical separation also called?

A

Allopatric speciation

58
Q

What is sympatric speciation?

A

Where a reproductive barrier arises. Could be due to biochemical change which prevents fertilisation. Could be a behavioural change, or physical change where the sexual organs of the two groups of individuals are no longer compatible and they cannot mate.

59
Q

What interesting facts did darwins fossils show/

A

In the past the world had been inhabited by species that were different from those present today
Old species have died out
New species have arisen
New species that appeared are often similar to the older ones found in the same place

60
Q

How does evolution occur?

A
  1. Variation must occur before evolution can take place
  2. Once variety exists, then the environment can ‘select’. It will select those variants that give an advantage
  3. Individuals with an advantage will survive and reproduce
  4. Therefore they pass on their characteristics
  5. The next generation will be better adapted to it environment
61
Q

In what 3 ways can a population of a species evolve to become a whole new species ?

A

The population of the species migrates to a new environment
Environmental change affects only some populations of the species
If there is a reproductive barrier preventing some populations of the species from interbreeding - these populations then evolve along different paths according to their local environment, and these changes cannot be passes to the rest of the species

62
Q

Which two different ways explain how insects have become resistant to insecticides?

A

Insects may be able to break down insecticide (using enzymes) - they metabolise them
The target receptor protein on the cell membrane may be modified

63
Q

Why must humans be careful with the insecticides they kill insects with?

A

The insecticide could enter the food chain and humans could actually end up consuming large amounts of insecticide

64
Q

What is extinction?

A

When a species ceases to exist

65
Q

How can human activities affect nature?

A

We have learned to use the environment to our advantage
Our numbers have risen dramatically - and continues to rise
Using more and more of the Earth’s resources
Activities harm other species, either directly or indirectly
Loss of biodiversity occurs
Extinction may occur

66
Q

Give 6 human activities which reduce biodiversity and cause extinction

A

Hunting for food (over-harvesting)
Killing for protection - attempting to kill insects that are vectors of disease or to remove the threat of a predator
Killing to remove competitors for our food
Pollution
Habitat destruction, such as deforestation or clearing for development or agriculture
Inadvertent introduction of new predators and competitors to natural flora and fauna

67
Q

List what 4 things that would threaten a species with low genetic biodiversity

A

Changes to the climate
Increase in levels of pollution
Emergence of new diseases
Arrival of new pests

68
Q

How do humans reduce genetic diversity?

A

We clear natural vegetation, reduce the size of natural habitats, reduce population size, reduces overall gene pool, decreases genetic variation and hence the ability of the species to evolve

69
Q

What is genetic erosion?

A

Modern agriculture uses monoculture and selective breeding. This reduces variation and genetic diversity of domesticated plants and animals. Also leads to the extinction of some varieties within a species

70
Q

Give 4 obstructions which could prevent the migration of a species

A

Major human developments
Agricultural land
Large bodies of water
Humans

71
Q

How can agriculture negatively affect the environment and biodiversity?

A

Higher carbon dioxide level affecting photosynthesis
Higher temperatures increasing growth rates
Longer growing seasons
Greater evaporation of water and therefore greater precipitation
Loss of land due to rise in sea level and increased salinity of the soil

72
Q

Why is it bad for a crop to be grown in a new area?

A 
New diseases
New pests 
longer growing season means pests grow in numbers
greater infestation
lower yields
less food for humans
73
Q

Give a reason for conserving biodiversity

A

Natural solution to some of our problems
So important to maintain wild plants and animals due to the potential that exists in the wide range of species that exists

74
Q

What is conservation in situ?

A

means conserving a species in its normal environment

75
Q

How do you choose if an environment is suitable to be a national park?

A

Is there enough species present in the area?
Is the area large enough?
Is there a full range of diversity within each species?

76
Q

What advantages come with designating a nature reserve?

A

Plant and animals are conserved in their natural environment
Protects biodiversity
Protects natural and cultural heritage
Management so that ecological integrity is maintained
Ecologically sustainable land uses
Facilitates biological research
Restore ecological integrity

77
Q

Give 4 reasons why conflict could occur with indigenous people when deciding on a nature reserve

A

Protected animals coming out of the reserve to raid crops
People continuing to hunt protected animals for food
Illegal harvesting of timber and other plant products
Tourists feeding protected animals or leaving litter

78
Q

What is conservation ex situ?

A

Conserving endangered species by activities that take place outside its normal environment

79
Q

Why can captive breeding be difficult?

A

Animals not in their natural environment
Space is limited
Decrease in genetic diversity
Species are less able to adapt
Animals have to survive being re introduced into the wild
Difficulties with acceptance with members of the wild

80
Q

How are plants able to be conserved?

A

Seeds are collected
They are stored and germinated in protected surroundings
Bred asexually
Botanical garden can increase the numbers very quickly
Provide ample supply for research
Captive-bred can be replanted in the wild

81
Q

What are the disadvantages of conserving plants?

A

Any collection of wild seeds will cause some disturbance
Seeds collected from the same species from another area will be genetically different
may not succeed in a different area
Seeds stored for any length of time may not be viable
Plants bred asexually will be genetically identical - reducing genetic diversity
Conclusions from a small sample may not be viable for the whole species

82
Q

How do scientists carry out germination tests?

A

‘plant’ seeds in petri dishes in controlled conditions
Measure germination rate and the success of germination
Enables scientists to monitor the condition of the stored seeds

83
Q

What is the Environmental impact assessment?

A

A procedure to assess the likely significant effects that a proposed development may have on the environment

A-level biology (18 decks)

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