Biology (4.2): Biodiversity

Biodiversity

Biodiversity

a measure of the habitat, species and genetic diversity of an environment

Habitat

where an organism lives

habitat diversity

the variety of different habitats in an environment

species diversity

the variety of different species in an environment

genetic diversity

the variety of different alleles in a particular species genepool

species

a group of organisms that can freely interbreed to produce fertile offspring

species richness

number of different species at a given time

species evenness

the degree to which the species are represented

sampling

measuring small portions of a larger population to make assumptions to the whole population

What does sampling do?

establishes a representative estimate when it would be difficult to sample all of a population

What are the four types of sampling (4)

1. random

2. stratified

3. opportunity

4. systematic

random sampling advantages (3)

1. removes bias

2. making comparisons between locations

3. estimate populations

Random sampling weaknesses (4)

1. may not cover all areas of habitat equally

2. species with low population numbers may be missed

3. under-estimates biodiversity

4. uneven distribution of organisms may give inaccurate data

Opportunistic sampling

researcher makes sampling decisions on prior knowledge and sites are chosen deliberately for the presence of a species and sampling then takes place in this location

opportunistic sampling advantages (2)

1. easier/quicker to get data

2. useful if distribution is uneven

opportunistic sampling disadvantages (2)

1. bias

2. over-estimates biodiversity

Stratified sampling

The habitat is divided into strata based on environmental features and then proportionally sample each strata

stratified sampling strengths

ensures that different habitats are proportionally represented

stratified sampling weaknesses

species/habitats may get over-represented if not correctly stratified

systematic sampling

samples are taken at fixed intervals across the habitat

Systematic techniques

line and belt transects

systematic sampling advantages (2)

1. useful to measure gradual change across a habitat

2. useful if particular factor has a gradient

systematic sampling weaknesses (2)

1. line/belt may miss many species

2. under-represents biodiversity

What equipment can be used to sample plants? (3)

1. frame quadrat

2. point quadrat

3. transect line using string or tape

ACFOR scale

abundant, common, frequent, occasional, rare

What equipment can be used to sample animals? (4)

1. sweep nets

2. kick sampling

3. pitfall traps

4. tullgren funnels

What are tullgren funnels used for?

separating insects from soil or leaf litter

What can be used as quantification for animal samples? (3)

1. frequency

2. index of diversity

3. mark-release-recapture

Simpson’s Index of diversity

a measure of both species evenness and richness combined

Large index

high diversity

small index

low diversity

allele

version of a gene

locus

position of a gene on a chromosome

polymorphic gene locus

a locus that has more than two alleles

proportion of polymorphic gene loci =

number of polymorphic gene loci / total number of loci

what affects biodiversity? (4)

1. human population growth

2. agriculture

3. climate change

4. extinction

How does human population growth affect biodiversity? (4)

1. alter ecosystems to provide food

2. destroy and fragment habitats

3. using Earth’s resources

4. pollute atmosphere

How does agriculture affect biodiversity? (4)

1. decrease size of habitats

2. reduces genetic diversity

3. leave isolated and fragmented populations

4. monocultures

How does selective breeding affect biodiversity? (2)

1. reduce genetic diversity

2. genetic erosion

How does climate change affect biodiversity? (2)

1. decrease genetic diversity

2. species less able to adapt to changes in temperature and rainfall

What are some obstructions to migration? (4)

1. major human developments

2. agricultural land

3. large bodies of water

4. mountain ranges

What does having a good diversity do?

increases adaptability to changing environments as it allows for natural selection and decreases likelihood of genetic disease

What does having bad uniformity do?

reduce likelihood of being able to adapt to changing conditions and reduces natural selection

Examples of selective breeding (3)

1. domesticated dogs

2. domesticated cattle

3. monocultures for food crops

Steps of selective breeding

1. organisms with desired characteristics are bred together to produce offspring with similar characteristics

2. offspring with characteristic chosen are bred together

3. repeated over many generations

Founder effect (3)

1. migration of a few colonisers

2. bring a small sample of alleles to a new environment

3. less genetic diversity results from future populations so they are less able to adapt to changing conditions

What does human populations introducing species result in?

the Founder Effect

What does humans destroying or fragmenting habitats and climate change cause?

genetic bottlenecks

Genetic bottlenecks (3)

1. dramatic population decrease

2. reduce number of types of alleles possessed by a species population

3. reduction in diversity (less able to adapt to changes in environment)

Reasons for maintaining biodiversity (3)

1. ecological

2. aesthetic

3. economic

keystone species

a species which has a large impact on an ecosystem when removed

What are crop wild relatives?

genetically diverse wild relatives of crop species

Why do crop wild relatives need to be protected?

they can provide valued genetic diversity if bred with crops

What are the ecological ways to maintain biodiversity? (2)

1. protecting keystone species

2. protecting keystone species

What are the aesthetic reasons to maintain biodiversity?

Nature is important for people’s wellbeing and physical, intellectual and emotional health

soil depletion

the loss of soil fertility caused by removal of minerals by continuous cropping

Economic reasons to maintain biodiversity (6)

1. purification and retention of fresh water

2. formation and fertilisation of soil

3. recycling of nutrients

4. crop pollination

5. growth of timer, food and fuel

6. discovery of medicine sources

Types of conservation (2)

1. in situ

2. ex situ

conservation

maintaining or increasing biodiversity through dynamic and ongoing management

Conservation in situ

carrying out active management to maintain the biodiversity in the natural habitat

Conservation ex situ

conservation outside the normal habitat of the species

Examples of conservation in situ (2)

1. wildlife reserves

2. marine conservation zone

Examples of conservation ex situ (3)

1. zoos

2. botanic gardens

3. seed banks

Advantages of in situ conservation (4)

1. organism remains in own environment

2. conserved land can be used sustainably to provide local economic benefits

3. facilitates scientific research

4. improve and restore ecological integrity of the area

Disadvantages of in situ conservation (4)

1. own habitat damaged due to fragmentation

2. population is too genetically uniform (lost genetic diversity)

3. endangering factors still present

4. attract poachers

Advantages of ex situ conservation (5)

1. protection from poaching and predation

2. easier to monitor health and treat disease and vaccinate

3. seed storage requires little room

4. raise funds

5. IVF or cloning can be carried out

Disadvantages of ex situ conservation (5)

1. inbreeding

2. increased disease due to higher densities

3. captive environment prevent breeding

4. costly biotic or abiotic requirements

5. limited genetic diversity

International example of conservation agreements (2)

1. CITES

2. The Rio Convention

What does CITES stand for?

the Convention on International Trade in Endangered Species

Local example of a conservation scheme

The Countryside Stewardship Scheme

What does CITES do? (2)

1. Bans international trade of certain endangered species

2. Regulates international trade in certain endangered species

Aims of The Rio Convention on Biological Diversity (4)

1. conserving biodiversity

2. sustainable use of resources from endangered organism

3. shared access to and benefit from genetic resources from organisms

4. sharing scientific knowledge

Aims of the Countryside Stewardship Scheme (3)

1. improve beauty and diversity of natural settings

2. enhance, restore and re-create targeted landscapes

3. improve public benefit and access

What was the Countryside Stewardship scheme replaced with in 2005?

The Environmental Stewardship Scheme

What does the Environmental Stewardship scheme aim to do?

help provide funding and advice to help land managers to conserve, enhance and promote the countryside

How does the Environmental Stewardship scheme aim to promote the countryside? (5)

1. looking after wildlife and habitats

2. ensuring land well managed

3. protect historic features and natural resources

4. ensuring traditional livestock and crops are conserved

5. provide learning opportunities