3.4e Biodiversity

State image definitions?

Biodiversity

The greater the number of different alleles in the gene pool of a population the more …1.?.

This increases genetic variation and allows for better adaptation to a changing …2?

This is because species with greater genetic biodiversity are more likely to survive …3? to their environments.

Species richness:

4. What is species richness?

5. Give a brief overview of how it can be measured?

   Note: The more species present in a sample, the higher the species richness

6. Give 3 problems of measuring species richness?

1. Diversity

2. Environment

3. Changes

4. The number of different species living in an area.

5. It is measured by taking a random sample of a community and counting the number of species present.

6. *It takes no account of the number of individuals of each species present

   *one daisy has as much influence on the richness of an area as 1000 buttercups. (Only counts as 2 species)

   *you should also measure the number of individuals in each species too! (Gives an idea of distribution of species)

Image info and other image shows example of works the index.

The largest cause for human impact on biodiversity is a result of converting large amounts of land for …1? Why?

2. The changes all reduce biodiversity in similar ways: Name 3 ways?

1. Agriculture: so farmers can maximise the amount of food produced in a specific area of land.

2. • The number of food sources is reduced as plants or animals are removed

   • Habitats are removed or destroyed which removes shelter for animals

   • Removal of habitats and food sources causes organisms to die or leave (migrate) to another area which further reduces biodiversity

Deforestation

Removal of …1? to increase the area of farmland, …2? the number and diversity of tree …3?. Also Removes of habitat and food sources.

Hedgerow Removal

This Increases the area of farmland by removing …4? which separate fields so they can be …5? into larger fields.

They’re Removed as they can be a source of insect …6? which eat crops, and …7? which can compete with crops.(- both can reduce yield.)

Monoculture

Farmers plant fields containing only …8? species of plant so Biodiversity is …9? and it will support fewer organisms as a food source or habitat which further decreases biodiversity

1. Trees. 2. Reduces. 3.species. 4.hedges. 5.joined. 6.pests. 7.weeds. 8. One. 9.reduced

• Pesticides - sprayed on crops to kill insect …1? which feed on them to …2? yield. Directly reduces number of insect …3? but also reduces …4? source for organisms which feed on these insects too.

• Herbicides - sprayed on unwanted plants (weeds) which could compete with crops for …5?, …6? (fertiliser) and …7?. Directly reduces …8? diversity in and around field and also reduces …9? sources for organisms which feed on these plant species

1. Pests. 2.increase. 3.species. 4. Food. 5,6,7. Water,minerals,sunlight. 8.plant. 9. Food