4.2.1 Biodiversity

Question 1

Biodiversity - Topic 2.1

Answer 1

Biodiversity - Topic 2.1

Question 2

What is biodiversity?
What is its importance?

Answer 2

The variety of living organisms present in an area.

Importance:
- essential in maintaining a balanced ecosystem for all organisms
- all species are interconnected (dependent on each other)
- we rely on balanced ecosystems as they provide us with the food, oxygen, and other materials needed to survive
- many human activities can lead to a reduction in biodiversity

Question 3

Why is it important to measure biodiversity?
What is an EIA?
What are the three different levels of biodiversity?

Answer 3

It plays an important role in conservation as:
- it informs scientists of the species that are present which provides a baseline for the level of biodiversity in that area; effect of any changes to an environment can be measured
EIA: environmental impact assesment:
- attempts to predict the positive and negative effects of a project on the biodiversity in that area
Levels:
- habitat biodiversity
- species biodiverstiy
- genetic biodiversity

Question 4

Habitat biodiversity

Answer 4

Refers to the number of different habitats within an area
- each habitat can support a no. of different species
- the greater the habitat biodiversity, the greater the species biodiversity in that area

Question 5

Species biodiversity
What is species richness and what is species eveness?

Answer 5

2 components:
- species richness: the no. of different species living in a particular area
- species evenness: a comparison of the no. of individuals of each species living in a community

Therefore, an area can differ in its species biodiversity even if it has the same no. of species.

Question 6

Genetic biodiversity

Answer 6

Refers to the variety of genes that make up a species
- gentic biodiversity within a species can lead to quite different characteristics being exhibited
- greater gentic biodiversity within a species allows for better adpatation to a changing environment, and is mroe likely to result in individuals who are resistant to disease

Question 7

What is sampling?
What are it uses?

Answer 7

Taking measurements of a limited number of indiviudal organisms present in a particular area

Uses:
- estimation of the number of organsims in an area (abundance)
- measuring particular charcateristics of an organism

Question 8

Random sampling

Answer 8

• Selecting individuals by chance
• in a random sample, each indiviudal in the population has an equal likelihood of selection, [like picking names out of a hat]
• random tables or computer programmes can be used
• no human involvement in deciding which organism to investigate

Question 9

3 types

Non-random sampling

Answer 9

An alternative sampling method where the sample is not chosen at random

• Oppurtunistic sampling: weakest form of sampling as it may not be representative of the population; it uses organisms that are conveniently available.
• Stratified sampling: some populations can be divided into a number of strata (sub-groups) based on a particular charcteristic; a random sample size is then taken from each of the strata proportional to its size.
• Systematic sampling: different areas within an overall habitat are identified which are then sampled seperately.

Question 10

Reliability of sampling

Answer 10

A sample is never entirely respresentative of the organsims present in a habitat. This may be due to:
- sampling bias
- chance

Question 11

What are the 6 sampling techniques?
Which are used for animal sampling and which are used for plant sampling?

Answer 11

Animal sampling:
1) Pooter
2) Sweep net
3) Pitfall trap
4) Tree beating
5) Kick sampling

Plant and animal sampling:
6) Quadrat

Question 12

What is human influence on biodiversity?
What 3 main problems are occruring as a result?

Answer 12

The human population is growing faster tha ever due to imrovemetns in medicine, hygiene, housing and infrastructure, people can live for longer.

1) Deforestation: The permanent remval of large areas of forest ot provide wood for building and fuel and to create space for roads, builfing and agriculture
2) Agriculture: Inc. amount of land has to be famred in order to feed the growing population which has led to large amounts of land being cleared and monoculture
3) Climate change: Inc. global temperatures due to the release of CO2 and other polllutants intot he atmoshphere from the burnign of fossil fuels

Question 13

Measuring genetic biodiversity

What is a poylmorphic gene?
What is polymorphism?
How do you calculate the proportion of polymorphic gene loci?

Answer 13

It is a gene with more than 2 possible alleles.

A technique that quantifies genetic biodiversity so it can be measured

The greater the proportion of polymoprhic gene loci, the greater the genetic biodiversity within the population.

proportion of polymorphic gene loci = (no. of polymorphic gene loci / total no. of loci) x100

Question 14

What needs to occur for genetic biodiversity to increase?
What 2 ways can this happen by?

Answer 14

The number of possible alleles in a population must also increase.

Mutation: A change in the genetic material whihc may affect the phenotype of the organism
- this creates new alleles which increases genetic biodiversity

Interbreeding between different populations:
- When an indivdual migrates from one population and breeds with a member of another population, alleles are transferred between the 2 populations.

Question 15

What are the aesthetic reasons for maintaining biodiversity?

Answer 15

• people enjoy visiting attractive environments as tourists
• the natural world provies inspiration for art, music, and writing
• people find beachs, woodlands, and parks relaxing and calming
• patients can recover from injuries and stress more quickly in a natural environment

Question 16

What is ‘in situ’ conservation?
How many in situ conservation methods are there?

Answer 16

Conservation within the habitat.

9 methods

Question 17

Why do conservation agreements exist?

Answer 17

• cooperation on a local, nationl, and international scale is needed to ensure habitats and particular species are conserved
• animas move between countries when alive, so protection is needed across borders
• animals and plants can be traded internationally so cooperation is needed to prevent over-exploitation
• climate change and sustainable develoment are linked to biodiversity and effect countried worldwide

Question 18

What is species diversity?

Answer 18

• One way to measure the biodiversity of an area
• The greater the species diversity, the greater the stability
• Most stable communities have large numbers of evenly distributed species in good sized populations

Question 19

Measuring biodiversity

What does the Simpsons Index of Diversity take into account?
How do you calculate it?

Answer 19

• species richness
• species evenness

D = 1 - ∑ (n/N)^2
diversity = 1 - the sum of (total no. of organisms of a particular species / total no. of organisms of all species)^2

Results always btween 0 and 1
0= no diversity
1= infinite diversity
the high the value of D, the more diverse the habitat

Question 20

Measuring genetic biodiversity

What is a genetic bottleneck?

Answer 20

Where few individuals within a population survive an event/change thus reducing the ‘gene pool’. Only the alleles of the surviving members of the population are available to be passed on to offspring.

Question 21

Why is it important for a species to be more genetically biodiverse?

Answer 21

It is essential for the survival of a species. Species that contain agreater genetic biodiversity are likely to be able to adapt to changs in their environmetn and therfroe are less likely to become extinct.

The higher the number of alleles within a species, the more geneticlly biodiverse they are

Question 22

What needs to occur for genetic biodiversity to decrease?
What 8 ways can this happen by?

Answer 22

The number of possible alles in a population must also decrease

Selective breeding:
- only a few individuals within a population are selected for their advantageous characteristics and bred
Captive breeding programmes:
- in zoos and conservtion centres, where only small no.s of captive individuals of a species are available for breeding => often the wild population are endagered/extinct
Rare breeds:
- historic selective breeding - only small no. are available for breeding. characteristics become less popular/unfashionable, so the no. of the breed fell catastrophically
Artifical cloning:
- asexual reproduction = genetically identical
Natural selection:
- species will evolve to contain primarily the alleles whihc code for the advantageous characteristics
- over time, advantageous alleles will be lost or only remain in few individuals from the population
Founder effect:
- small no. of individuals create a new colony, geographically isolated from the original
- gene pool for this is very small
Genetic bottleneck:
- few individuals of a population survive an event/change this educing the gene pool
- only alleles from surving members of population are available to be passed on
Genetic drift:
Due tp the random nature of aleles being pased on to offpsring from parents, frequency of occurence of an allele will vary
in some cases allele can disappear from a population altogether

Question 23

What is gene flow?

Answer 23

The transfer of alleles between a population.

Question 24

What is a gene pool?

Answer 24

The sum total of all the genes in a population at a given time.

Question 25

What are the economic reasons for maintaining biodiversity?

Answer 25

• using timber non-sutainbaly can remove that resoucre from an area and cause the industry to collapse
• species that could give rise to new chemicals or medicines become extinct before thay are discovered
• loss of pollinators can lead to less pollinaton among crop plants
• wild relatives of crop plants may contain genes that could be sued to improve crops through genetic engineering or selectiv breeding
• hihg biodiversity can protect agaisnt abiotic stress and disease - without it while crops can be lost
• deforestation can lead to soil erosion and desertifictio which can create poor soil quality that crops do not grow well in

Question 26

ecological is to maintain te ecosystem in a good state

What are the ecological reasons for maintaining biodiversity?

Answer 26

• removal of akeystone species can have a large impact on the species richness and eveness in a habitat
• continuous monocultrue leads to soil depletion as crops are rmeved without leaving nutrients in the soil. farmers hvae to compensate for this with the addition of fertilizers, pesticides, an dherbicides
• removal of one species can remove a food source or habitat for another species
• loss of polliantors can lead to less polliantion among wild plants

Question 27

What are keystone species?
What is an example of them?

Answer 27

They are species which have a significant impact on an ecoystem and their removal usually has a big impact on another species.

They are often predators e.g. sea stars - removal of the sea stars result in overpopulation of mussels and sea urchins as they have no other natural predator. the population explosion results in them outcompeting other species e.g. limpets reducing biodiversity.

Question 28

What is ‘ex situ’ conservation?
How many ex situ conservation method are there?

Answer 28

Conservation out of the natural habitat.
3 methods

Question 29

In situ

How do marine conservation zones aid conservation?
What are some problems with MPA’s (marine protected areas)?

Answer 29

• The fish live longer, grow larger, reproduce much more, and breed a lot.
• The fish eggs also get carried by tides anf dish migrate therfore it’s benefits are felt outside of MPA’s too

Problems:
- only cover ~7% of the world’s oceans
- Poor enforcement of regulations
- It includes a low diversity of habitat types- the same kinds of areas are being protected

Question 30

In situ

How do wildlife reserves aid conservation?
What are some problems with wildlife reserves ?

Answer 30

Government designated ares for wildlife
conservation parks:
- chosen carefulyy
- conserves plants and animals in natural environment
- managed

Problems:
- level of protection varies hugely between different wildife reserves
- some areas selected based on convenience and cost rather than ecological value
- lack of fuding and inadequate staffing
- effectiveness difficult to measure as research is weak and lack of baseline data
- protections offered often lacking and exploitation continues (peopel continue to hunt protected animals)

Question 31

In situ

How does feeding animals aid conservation?

Answer 31

• Feed so live and so they are heallhty and so they reproduce

Question 32

In situ

How does the reintroduction of a species aid conservation?
What are some problems with this- beaver example ?

Answer 32

• Reintroduce species in hopes of improving biodiversity
• hope to not ruin the biodiversity
• corrects an ecosystem and keeps a balance

Problems:
- they were reintroduced to scotland whihc caused food damage
- this ruined farmed land as beavers built dams
- this cost money as land is unused and no profit is being made from it (can’t farm on flooded land)

Question 33

In situ

How does removing invasive species aid conservation?
What are some success stories? (Galapagos invasive species)

Answer 33

• Removing the negative effect a species has on an ecosystem
• especially important if the species is invasive

Success story:
- invasive goats on galapagos island were killed using shooters so the turtles could thrive

Question 34

In situ

How does controlled grazing aid in conservation?

How does resticting human access aid in conservation?

Answer 34

• Grazing animals in particular areas which helps to increase biodiversity
• reserves areas and protets wildlife by preventing humans from acessing areas of important biodiversity

Question 35

In situ

How does controlling poaching aid in coonservtion?

Answer 35

• animals guarded by rangers patrolling the area for poachers
• remove the baluable part of an animal so people do not kill them for it; e.g. horn of rhino or tusks of elephant

Question 36

In situ

How does reforestation help to aid conservation?
What are the advantages and disadvantages of the grain for green programme?

Answer 36

• Plat new trees

Advantages:
- paid farmers to convert land back into forest
- higher annual income for the farmers
- more than 5 million hectares of forest is reintroduced

Disadvanatges:
- non-native breeds are planted by farmers and tree monocultures are created

Question 37

Ex situ

How do seed banks aid conservation?

Answer 37

• store a represntative seed sample from every known plant species
• seeds stored until they are needed
• stored in conditions so they will last decades; maybe centuries
• testing of seeds to check if thye will germinate

Question 38

Ex situ

How do botanic gardens aid conservation?

Answer 38

• speies activally mnaged to provide them with the best resources to grow
• plant species can be grown succesfully in botnic gardens
• ~1500 botanic gardens worldwide, holding 35000 plant species

Question 39

Ex situ

How do zoos aid conservation?
What are some problems with captive breeding?

Answer 39

• captive breeding programme- produce offspring in a human-controlled environment
• aim to create a healthy, stable population of a species, and then gradually reintroduce the species back into its natural habitat
• provide animal with good shelter and best treatment

Problems:
- maintaining genetic diversity within a captive breeding population is difficult
- problems relating to interbreeding can occur as only a small number of breeing partners are available

Question 40

What is the environmental stewardship scheme?
What are its aims?

Answer 40

• a local scheme in england set up in 1991
• offers government payments to farmers and land managers to conserve the English landscape

Aims:
- sustaining beauty and diversity of the landscape
- improving, extending and creating wildlife habitats
- resotring neglected land and onserving archaelogical and historic features
- improving opportunities for countryside development

Question 41

International agreement 1

What is the IUCN?

Answer 41

International Union for the Conservation of Nature
- publishes the red list which gives the current status of threatened species

Question 42

International agreement 2

What are CITES?

Answer 42

Convention on International Trade in Endagered Species
- regulates the international trade of wild plant and animal species

Question 43

International agreement 3

What is the Rio Convention?

Answer 43

• meeting of 172 nations which became the Earth Summit, to create agreements between the countries for biodiversity

Question 44

What are the features of low biodiversity habitats?

Answer 44

• relatively simple food web
• relatively few ‘succesful’ species
• changes to the envionment has major effects to the ecosystem
• relatively few species live in the habitat, often with very specific adapatations for the environment
• stressful/extreme nature of environment with few ecological niches

Question 45

What are the features of high biodiversity habitats?

Answer 45

• complex food web
• large number of ‘succesful’ species
• often relaively small effect of chnages to envionment on ecosytem as a whole
• many species live in the habitat, often with few specific adaptations to the environment
• relatively benign/not stressful nature of environment with more ecological niches

Question 46

How can a pooter be used to collect small insects?

Answer 46

By sucking on a mouthpiece, insects are draw in into the holding chamber via the insect tube.

Question 47

How can a pitfall trap be used to sample invertebrates?

Answer 47

A hole is dug in the ground and insects fall in deep so they can’t crawl out.
It is covered with a roof structure so that no rainwater can get in.
The trap is left overnight so nocturnal species are sampled too.

Question 48

How can tree beating be used to collect invertebrates?

Answer 48

A large white cloth is strethced under a tree.
The tree is then shaken/beaten to dislodge the invertebrates.
Animals fall onto the sheet where they an be collected and studied.

Question 49

How can kick sampling be used to study organisms lying in a river?

Answer 49

The riverbank and bed is ‘kicked’ for a eriod of time to disturb the subsstrate.
A net is help downstream for a set period of time in order to capture any organisms released into the flowing water.

Question 50

When is a sweep net used?

Answer 50

It is helpful in aread of long grass

Question 51

What are the two types of quadrats?
How are they used?

Answer 51

1) Point Quadrat:
Consists of frame containing a horizontal bar. Long pins can be pushed thoruhg bar @ set intervals along it to reach the ground. Each species of plant the pin tocuhed is recorded.
2) Frame Quadrat:
Consists of square frame divided into a grid of equal sections. The type and no. of species within each section of the quadrat is recorded

Question 52

Which animals are sampled using a quadrat?

Answer 52

Slow-moving animlas such as limpets or barnades.
Usually used to sample plants.

Question 53

What is an abiotic factor?
Why is it advantageous to mesure abiotic factors using sensors?

Answer 53

A non-living condition in a habitat.

• a hihg degree of precision can be used
• quantitative
• rapdi changes can be detected
• human error is reudced
• data can be stored and tracked on a computer

Question 54

What are the 3 ways to use a frame quadrat?

Answer 54

Density?
- if individual plants can be clearly seen, count no. of them in a 1m by 1m square quadrat
- this gives density per square metre
- then scale up

Frequency?
- if individual members of a species are hard to count, use small grids within the quadrat, and count the no. of squares a particular species is present in
- random sampling

Percentage cover:
- useful when a particular species is abundant/difficult to count.
- used for seed and lots of data can be collected quickly
- estimate by eye of the area within a quadrat that the plant covers
- then scale up.

Question 55

Why is it often difficult to accurately determine the size of animal populations?

Answer 55

Animals are constantly moving through a habitat and others may be hidden.

Question 56

How can you estimate the animal population size using mark and recapture method?

Answer 56

1. capture as many of the organsims as possible the first time
2. mark them and release ak into community
3. allow time for organisms to redistribute themselves thoruhgout the habitat before sampling them again
4. re-capture and compare no. of marked individuals with no. of unamrked indiviudals in second sample = estimates population size

equation:

total marked/ total popualtion = total marked second time/ total marked

Question 57

How is species richness calculated?

Answer 57

1. Use combination of smapling techniques to try and identify all the species wihtin a habitat.
2. Compile a list of each species identified.
3. Total no. of species can then be calculated.

Question 58

How is species evenness calculated?

Answer 58

1. count the no. of different species ther are in a habitat and how many of each species
2. use the capture-recapture technique for all the species and compare the total no. of each organism present

Question 59

What ways can deforestation occur?

Answer 59

1. naturally due to froest fires caused by lgihtning, extreme heat, or dry weather
2. direculty due to human acitivity as humans cut down trees
3. indirectly due to human activity due to acid rain which forms due to pollutants being released into the atmsophere

Question 60

What ways can deforestation affect biodiversity?

Answer 60

1. reduces no. of trees present in an area
2. species diversity reduced if only one tree type is felle
3. reduces no. of animal species present in an area as it destroys their habitat and food source.
4. animals are forced to migrate to toeher areas to ensure their survival

Question 61

What agriculutral methods affect biodiversity and how?

Answer 61

1. Selecting species:
chosen based on charactersitics that give a high yield and this reduces biodiversity of area
2. Removal of hedgerows:
done to allow use of large machinery on farm- reduces no. of plant species present in an area nd destorys habitat of many animals
3. Use of pesticides: (used to kill pests that would eat crops or live on animals)
reduces species diversity as it destorys the pest species and destorys food source of other organisms
4. Use of herbicices: (used to kill weeds)
reduces plant diversity. also destorys species diversity as may be food source of other organisms
5. Monoculture: (clearing large amounts of land and planting a single crop)
lowers biodiversity enormously locally as only one species of plant is present. lowers overall biodiversity as only a few animla species will be supported by one plant.

Question 62

What are 4 possible impacts of climate change on biodiversity?

Answer 62

1. Melting of the polar ice caps could lead to extinction of the few pant and animal speccies lvign in these regions and increasing global temepratures wold allow temeperate plant and animal species to live further north than currently
2. rising sea levels from melting ice caps and the therma expansion of oceans could flood low-lying land, reducing the availbale terrestrial habitats and saltwater would flowfurther up rivers, reducing habitats of freshwater plants and animals lviing in the river and surrounding areas.
3. higher temps and less rainfall would result in some plant speceis failing to survive leading to drouhg-resitant species (xerophytes) becoming more dominant
4. insect life cycles and populations will change as they adapt to climate change ==> inseccts are key pollinators of plants so this could affec plants’ lives and lead to extincition.

Question 63

Why might a slow change in the climate actually increase biodiversity?

Answer 63

species may have time to adapt/migrate to other areas wchihc will lead to a loss of native sepcies
other species may move intot he area so biodiversity would not be lost
the species mix would simply change

Question 64

What i global wamring and why is it linked to human activity?

Answer 64

Global wamring: rise in Earth’s mean surface temperature
CO2 levels in the atmosphere have significantly inc. since industrial revolution, trapping more thermal energy in the atmosphere
therfore msot scientists believe that human activities are contributing to global warming