Biodiversity

Question 1

Species

Answer 1

A group of individual organisms very similar in appearance, anatomy, physiology, biochemistry and genetics, whose members are able to interbreed freely to produce fertile offspring

Question 2

Habitat

Answer 2

The place where an organism or a population lives. Includes the climatic, topographic and edaphic factors as well as the plants and animals that live there

Question 3

Biodiversity

Answer 3

The number and variety of living things to be found in the world in an ecosystem or in a habitat. Takes into account abundance of species, number of species and how many places they can be found

Question 4

‘Levels’ of biodiversity

Answer 4

• range of habitats in which different species live, e.g. lawns to ponds to dark corners to trees. Each habitat will be occupied by a range of organisms
• difference between species. Could be structural (e.g. tree and an ant) or functional (bacteria that cause decay and those that assist digestion)
• genetic variation between individuals of the same species - ensures we don’t look alike

Question 5

Importance of sampling in measuring biodiversity

Answer 5

To measure biodiversity, you must observe all species present, identify and count them all. This is impractical to do, especially considering single celled organisms. Therefore, we take study small samples of the habitat, and multiply up the numbers to obtain an estimate

Question 6

Taking random samples of plants

Answer 6

• chose number of samples, taking into account time, size and diversity
• measure percentage cover for grasses and herbs (use point quadrat)
• conduct visual survey to see what plants aren’t in the samples but are present (record, but with no frequency)
• use a quadrat and a random coordinate system
• can use an abundance scale, e.g. ACFOR
• can use a line/belt transect to measure change

Question 7

Sampling animals

Answer 7

• as they move, sampling can disturb
• don’t trap large animals. Either observe or identify from marks e.g. poo
• sweep netting: catches insects in vegetation
• collecting from trees: knock branches, catch stuff on sheet
• pitfall trap: animals will fall in

Question 8

Species richness

Answer 8

The number of species present in a habitat

Question 9

Species evenness

Answer 9

Abundance of individuals in each species

Question 10

Measuring species richness

Answer 10

Take a qualitative survey, making observations and recording all the species you see. Can take samples

Question 11

Measuring species evenness - plants

Answer 11

• take random samples

- count plants or measure percentage cover, depending on size of the plant

Question 12

Measuring species evenness (density) - animals

Answer 12

• take careful observations for larger animals
• trap smaller animals, using a mark and recapture technique to estimate density
• mark first lot of animals caught in a way that won’t cause them harm
• release them, wait for a bit to allow mingling, then capture some more
• count number captured, and number marked in second capture
• population=C(1)xC(2)/C(3)

Question 13

Simpson’s Index of Diversity

Answer 13

A formula used to measure the diversity of a habitat. D=1-(sum(n/N)^2)

Question 14

High Simpson’s Index of Diversity

Answer 14

Indicates a diverse habitat. Many different species and organisms live there. If there is a small environmental change, it may affect 1 species, but that species may only be a small part of the whole habitat. Therefore, the habitat tends to be stable and able to withstand change

Question 15

Low Simpson’s Index of Diversity

Answer 15

Indicates habitat is dominated by a few species. A small change to the environment, e.g. a disease or predator that affects one of those species could damage or destroy the whole habitat. Habitat is unstable, and unable to withstand change