CRAM - 4.2.1

What is biodiversity?

The variety and complexity of life in an area

Why is biodiversity important?

It indicates the health and stability of habitats

What are the three levels of biodiversity?

Habitat diversity

species diversity

genetic diversity

What is habitat diversity?

The variety of habitats within an ecosystem

Give examples of habitat diversity.

Sand dunes

woodland

meadows

streams

What is species diversity?

The variety of species

and the number of individuals of each species in a habitat

What are the two components of species diversity?

Species richness and species evenness

What is species richness?

The number of different species in a habitat

What is species evenness?

The relative abundance of each species in a habitat

What is genetic diversity?

Variation in alleles within a population or species

Why is high genetic diversity beneficial?

Increases ability to adapt to environmental change and resist disease

What is a species?

A group of organisms that can interbreed to produce fertile offspring

What is a habitat?

The place where an organism lives

Why is sampling important in biodiversity studies?

It is impractical to count every organism in a habitat

Why is random sampling used?

To reduce bias and produce representative samples

How is random sampling carried out?

Generate random coordinates and sample at those points

Why should random sampling be repeated many times?

To increase reliability and reduce the effect of chance

What is non random sampling?

Sampling where locations are chosen based on criteria or patterns

What is opportunistic sampling?

Sampling conveniently available organisms

Why may opportunistic sampling be unreliable?

It may not represent the whole population

What is stratified sampling?

Sampling from different subgroups in proportion to their size

What is systematic sampling?

Sampling at regular intervals across a habitat

What is a transect?

A line along which samples are taken

What is a line transect?

Samples taken at intervals along a single line

What is a belt transect?

Samples taken in an area along a line using quadrats

What is a continuous belt transect?

Quadrats placed side by side along a transect

What is an interrupted belt transect?

Quadrats placed at intervals along a transect

Why are transects useful?

They show changes in species distribution across a habitat

What is a quadrat?

A frame used to sample organisms in an area

What is a frame quadrat?

A square grid used to count organisms

What is a point quadrat?

A frame with pins used to record species touched

What types of organisms are sampled using quadrats?

Plants and non motile animals

What is species density?

Number of individuals per unit area

What is species frequency?

Percentage of quadrats a species appears in

What is percentage cover?

Estimate of area covered by a species within a quadrat

What is a pooter?

A device for collecting small insects by suction

What is a sweep net used for?

Sampling insects in grass or air

What is a pitfall trap?

A trap for small ground dwelling organisms

What is tree beating?

Shaking a tree to collect invertebrates onto a sheet

What is kick sampling?

Kicking a riverbed and collecting organisms in a net downstream

Why should the range of organisms in a habitat be sampled?

To get a representative measure of biodiversity

What are abiotic factors?

Non living environmental factors affecting organisms

Give examples of abiotic factors.

Light temperature humidity pH wind speed dissolved oxygen

Why are abiotic factors measured in investigations?

They affect the distribution of organisms

What equipment can measure abiotic factors?

Sensors and probes

What are advantages of electronic sensors?

Greater precision reduced human error and data storage

What is Simpson’s Index of Diversity used for?

Calculating biodiversity of a habitat

What does Simpson’s Index take into account?

Species richness and species evenness

What is the range of Simpson’s Index of Diversity?

0 to 1

What does a high Simpson’s Index value indicate?

High biodiversity

What does a low Simpson’s Index value indicate?

Low biodiversity

What does N represent in Simpson’s Index?

Total number of organisms of all species

What does n represent in Simpson’s Index?

Number of organisms of one species

Why does high species evenness increase biodiversity?

No single species dominates the habitat

proportion of polymorphic gene loci =

number of polymorphic gene loci/ total number of loci

What is a polymorphic gene locus?

A gene locus with more than one allele

What is a monomorphic gene locus?

A gene locus with only one allele

What does a high proportion of polymorphic loci indicate?

High genetic diversity

How can gene flow increase genetic diversity?

Introduces new alleles through interbreeding

How do mutations increase genetic diversity?

Create new alleles

How can selective breeding reduce genetic diversity?

Only selected alleles are passed on

How can captive breeding reduce genetic diversity?

Small breeding populations reduce allele variety

How can cloning reduce genetic diversity?

Produces genetically identical organisms

How can genetic bottlenecks reduce diversity?

Population size drops leaving few alleles

What is the founder effect?

A new population started by a few individuals

What is genetic drift?

Random changes in allele frequency over time

How does human population growth reduce biodiversity?

Destroys habitats and overuses resources

How does deforestation affect biodiversity?

Destroys habitats and reduces species diversity

How does urban sprawl affect biodiversity?

Isolates populations reducing gene flow

How does pollution reduce biodiversity?

Kills organisms and damages habitats

What is monoculture?

Growing one crop species over a large area

How does monoculture reduce biodiversity?

Reduces habitat and species diversity

Why does monoculture deplete soil nutrients?

The same crop repeatedly uses the same minerals

How does removing hedgerows reduce biodiversity?

Destroys habitats and food sources

How does draining marshes reduce biodiversity?

Destroys wetland habitats

How can herbicides reduce biodiversity?

Kill weeds and species dependent on them

How can pesticides reduce biodiversity?

Kill non target species

How can inorganic fertilisers harm aquatic ecosystems?

Runoff causes eutrophication

How can crop rotation help biodiversity?

Maintains soil nutrients and habitat variety

How can maintaining hedgerows help biodiversity?

Provides habitats and food sources

How does reducing pesticide use help biodiversity?

Protects non target organisms

How does climate change affect biodiversity?

Changes habitats and species distribution

Why are some species vulnerable to climate change?

They are adapted to specific conditions

How can climate change cause extinction?

Species may not adapt quickly enough

How does melting polar ice reduce biodiversity?

Removes habitats for polar organisms

How can warmer climates spread disease?

Tropical diseases expand into new regions

How can rising sea levels affect biodiversity?

Flood low lying habitats

Why is maintaining biodiversity ecologically important?

Ecosystems depend on interdependent species

What is a keystone species?

A species with a disproportionately large effect on an ecosystem

Why are keystone species important?

Their loss destabilises ecosystems

Why are decomposers important for biodiversity?

Recycle nutrients through ecosystems

How does biodiversity increase ecosystem resilience?

Greater variation improves survival against stress and disease

Why is biodiversity economically important?

Provides resources medicines and tourism income

Give examples of products from biodiversity.

Timber

biofuels

medicines

antibiotics

Why are microorganisms economically valuable?

Produce antibiotics and useful substances

How can biodiversity support future industries?

Provides genetic resources for new products

Why is biodiversity important in agriculture?

Provides disease resistance and genetic variation

Why are wild relatives of crops important?

Provide useful alleles for breeding

Why is monoculture economically harmful?

Causes soil depletion and lower yields

Why are pollinators important for agriculture?

Many crops depend on them for reproduction