4.1.2 - BIODIVERSITY

Question 1

Define Biodiversity

Answer 1

The variety of living organisms in an area

Question 2

Define Species

Answer 2

A group of similar organisms able to reproduce to give fertile offspring

Question 3

Define Habitat

Answer 3

The area inhabited by a species. It included the physical factors, like the soil and temperature range, and the living (biotic) factors, like availability of food or the presence of predators

Question 4

Define Habitat Diversity

Answer 4

The number of different habitats in an area.
e.g. a particular area could contain many different habitats - sand dunes, woodland, meadows, streams, etc..

Question 5

Define Species Diversity

Answer 5

The number of different species (species richness) and the abundance of each species (species evenness) in an area
e.g. a woodland could contain many different species of plants, insects, birds and mammals

Question 6

Define Genetic Diversity

Answer 6

The variation of alleles within a species (or a population of a species)
e.g. the variation of alleles within the dog species gives rise to different breeds, such as a Labrador or poodle

Question 7

Define Species Richness

Answer 7

The number of different species in an area. The higher the number of species, the greater the species richness. It is measured nu taking random samples of a habitat + counting the number of different species

Question 8

Define Species Evenness

Answer 8

A measure of the relative abundance of each species in an area. The more similar the population size of each species, the greater the species evenness. Measured by taking random samples of a habitat, and counting the number of individuals of each different species

Question 9

What are the three types of non-random samples?

Answer 9

• Systematic sampling
• Opportunistic sampling
• Stratified sampling

Question 10

What is systematic sampling?

Answer 10

Samples are taken at fixed intervals, often a long a line (every nth specimen). E.g. if you were counting plant species in a field, quadrats could be placed along a line (transect) from an area of shade in the corner to the middle of the field. Each quadrant would be a sample site

Question 11

What is opportunistic sampling?

Answer 11

Samples are chosen by the investigator. Simple but biased

Question 12

What is stratified sampling?

Answer 12

When different areas in a habitat are identified and sampled separately in proportion to their part of the habitat as a whole. E.g. a heathland may have patches of gorse in it - the heath and gorse areas would be sampled separately according to how much of each there was in the habitat

Question 13

What are the different types of sampling techniques?

Answer 13

Pitfall trap
Pooter
Tullgren funnel
Kick sampling
Sweep net

Question 14

What is a pitfall trap?

Answer 14

A small pit that insects can’t get out of

Question 15

What is a pooter?

Answer 15

A device that allows you to safely suck small insect through a tube into a jar

Question 16

What is a Tullgren funnel?

Answer 16

Soil or leaf litter sample is put on a mesh filter at the top of a funnel and a light is shone down onto it. Organisms move away from the heat created by the light and fall out of the funnel and into a collecting beaker

Question 17

What is kick sampling?

Answer 17

Gently kick the bottom of a stream then use a net to collect the organisms that have been disturbed

Question 18

What is a sweep net?

Answer 18

A net lined with a strong cloth on a pole

Question 19

When would random sampling be used?

Answer 19

To avoid bias in results
E.g. looking at a plant species in a field, you could pick random sample sites by dividing the field into a grid using measuring tapes and using a random number generator to select coordinates

Question 20

When would non-random sampling be used?

Answer 20

When there’s a lot of variety in the distribution of species in the habitat and you want to make sure all the different areas are sampled

Question 21

How to calculate Simpson’s Index of Diversity?

Answer 21

D = 1 - (∑(n/N) ²)

n - total number of individuals of one species
N - total number of organisms of all species
∑ - ‘sum of’ (i.e. added together)

Question 22

What is a locus?

Answer 22

Alleles of the same gene are found art the same point on a chromosome

Question 23

What is polymorphism?

Answer 23

A locus that has two or more alleles

Question 24

What is the calculation for proportion of polymorphic gene loci?

Answer 24

Proportion of polymorphic gene loci = number of polymorphic gene loci/total number of loci

Question 25

What are factors affecting global biodiversity?

Answer 25

• Human population growth
• Increased use of monoculture in agriculture
• Climate change

Question 26

How does human population growth affect global biodiversity?

Answer 26

• Habitat loss - human development is destroying habitats (e.g. deforestation in the Amazon for grazing and agriculture). Decreases habitat diversity
• Over-exploitation - A greater demand for resources (e.g. food, water + energy) means resources used up faster than replenished
• Urbanisation - Sprawling cities are major road developments can isolate species, meaning populations are unable to interbreed and genetic diversity is decreased
• Pollution - High amounts of pollutants can kill species or destroy habitats, e.g. high levels of fertiliser flowing into a river can lead to a decrease in fish species in that river

Question 27

How does increased use of monoculture in agriculture affect global biodiversity?

Answer 27

• Habitats are lost as land is cleared to make way for large fields, reducing habitat diversity
• Local and naturally occurring plants and animals are seen as week and pests, and so are destroyed with pesticides and herbicides, reducing species diversity
• Heritage (traditional) varieties of crops are lost because they don’t make enough money + so are not planted anymore - reduces species diversity

Question 28

How does climate change affect global biodiversity?

Answer 28

• Climate change is the variation in the Earth’s climate, e.g. things like changes in temperature and rainfall patterns
• Occurs naturally, but the scientific consensus is that the climate change we’re experiencing at the moment is caused by humans increasing emissions of greenhouse gases (e.g. carbon dioxide)
• Greenhouse gases cause global warming (increased global average temperature) which causes other types of climate change, e.g. changing rainfall patterns
• Climate change will affect different areas of the world in different ways - some places will get warmer, some colder, some wetter and other drier. All of these may affect global diversity

Changes in climate may mean that areas that were previously inhabitable become uninhabitable (or vice versa). May increase or decrease range of some species (e.g. southern range limit of Sooty Copper Butterfly moved 60 miles north in recent decades)
Species may be forced to migrate, changing species distribution + decreasing biodiversity in the areas the species migrate from
If there is no suitable habitat to migrate, the species is a plant and can’t migrate, or the change is too fast, the species may become extinct (e.g. corals - they die if water temp changes by 1 or 2 degrees)

Question 29

Define interdependence

Answer 29

Species depend on each other to survive

Question 30

What is a genetic resource?

Answer 30

Any material from plants, animals or microorganisms, containing genes, that we find valuable

Question 31

Give and explain ecological reasons for the conservation of biodiversity

Answer 31

• To protect species, including keystone species - Loss of a keystone species may disrupt food chains (some bear species feed on salmon, which feed on herring. If herring decline, salmon and bear populations are affected) and may disrupt nutrient cycles (e.g. decomposes like worms improve the quality of soil by recycling nutrients. If worm numbers decline, soil quality is affected, affecting plant growth
• To maintain genetic resources - they provide us with resources such as food, drink, clothing, drugs, fuels and other industrial materials. Genetic materials also allow us to adapt to changes in the environment (e.g. climate change may mean spoke crops can’t grow in areas there are now droughts. But can genetically engineer from crop that is resistant to droughts

Question 32

Give and explain economic reasons for the conservation of biodiversity

Answer 32

• Reduce soil depletion - monoculture is growing a single variety of a single crop. If continued, involves planting the same crop in the same field without interruption. Causes soil depletion because nutrients required by the crop are gradually used up.

Question 33

Give and explain aesthetic reasons for the conservation of biodiversity

Answer 33

• Areas rich in biodiversity provide pleasant, attractive landscapes that people can enjoy, by maintaining biodiversity we protect these landscapes
• The more biodiversity in an area, the more visitors the area is likely to attract - this has economic advantages

Question 34

What are some methods of in situ conservation?

Answer 34

• Establishing protected areas such as natural parks and wildlife reserves
• Controlling or preventing the introduction of species that threaten local biodiversity
• Protecting habitats
• Promting particular species
• Giving legal protection to endangered species

Question 35

What are some methods of ex situ conservation?

Answer 35

• Relocating an organism to a safer area
• Breeding organisms in captivity then reintroducing them to the wild when strong enough
• Botanic garden
• Seed banks

Question 36

What are advantages of in situ conservation?

Answer 36

• Both the species and their habitat are conserved
• Larger populations can be protected and it’s less disruptive than removing organisms from their habitats
• The chances of a population recovering are greater than with ex situ methods
• Cheaper than ex situ methods

Question 37

What are advantages of ex situ conservation?

Answer 37

• Can be used to protect animals in a controlled environment (hunting and predators can be managed)
• Can be used to reintroduce species that have left an area

Question 38

What are disadvantages of in situ conservation?

Answer 38

• Can be difficult to control some factors that are threatening a species (e.g. poaching, predators, disease _ climate change

Question 39

What are disadvantages of ex situ conservation?

Answer 39

• Usually only a small number of individuals can be cared for
• It can be difficult and expensive to create and sustain the right environment (animals that are used to human contact may be less likely to exhibit natural behaviour and more likely to catch a disease from humans
• Usually less successful than in situ methods - many species can’t breed successfully in captivity, or don’t adapt to their new environment

Question 40

Describe how botanic garden help in the conservation of biodiversity.

Answer 40

Controlled environment sued to grow a variety if rare koans for the purposes of conservation, research, display, and education. They are watered a healthy amount and fertilised

Question 41

Describe how seed banks help in the conservation of biodiversity.

Answer 41

Seeds can be frozen and stored in seed banks for over a century without losing fertility. Seed banks provide a useful source of seeds if natural reserves are destroyed (e.g. by disease or natural disasters)

Question 42

Describe how protecting habitats helps in the conservation of biodiversity.

Answer 42

Allows organisms to continue living in their natural habitat (e.g. controlling water levels to conserve wetlands and coppicing (trimming trees) to conserve woodlands

Question 43

Describe how promoting particular species helps in the conservation of biodiversity.

Answer 43

Could be protecting food sources or nesting sites