Biodiversity

Question 1

What is habitat diversity?

Answer 1

The number of different habitats found within an area

Question 2

How does habitat diversity affect overall diversity?

Answer 2

The greater the habitat diversity the greater the overall diversity

Question 3

Give some examples of habitats.

Answer 3

Meadow, woodland, stream, sand dune

Question 4

What is species richness?

Answer 4

Species richness refers to the number of different species living in a given area

Question 5

What is genetic biodiversity?

Answer 5

Refers to the variety of genes that make up a species

Question 6

What is species evenness?

Answer 6

A comparison of the number of individuals of each species living within a community

Question 7

How does greater genetic biodiversity affect a species?

Answer 7

It allows for greater adaptation to a changing environment and is more likely to result in individuals which are resistant to disease.

Question 8

What is sampling?

Answer 8

Taking measurements of a limited number of organisms within a particular area.

Question 9

What is meant by random sampling?

Answer 9

Selecting individuals by chance.

Question 10

How to carry out random sampling.

Answer 10

-Mark out a grid on the grass using two tape measures at right angles to each other
-Use random numbers to determine the x and y coordinate on your grid
-Take a sample at each of the coordinate pairs generated.

Question 11

Describe and explain the different types of non random sampling.

Answer 11

Opportunistic - using organisms that are conveniently available. This is the weakest form of sampling as it may not be representative of the whole population.
Stratified - some populations can be divided into strata based on certain characteristics. A random sample can then be taken from these strata proportional to its size.
Systematic - sampling different areas separately. Often carried out on a line belt or transect.

Question 12

What is a line transect?

Answer 12

Mark a line along the ground between two poles and take samples at specified points.

Question 13

What is a belt transect?

Answer 13

Two parallel lines are marked and samples are taken between the two lines.

Question 14

Give an example of sampling bias.

Answer 14

You may choose to sample an area which has more flowers because it looks more interesting

Question 15

Give some example of sampling methods with animals.

Answer 15

Pooter - by sucking on a mouthpiece insects are drawn into the chamber.
Sweep nets
Pitfall traps - dig a hole in the ground that insects can fall into and cover with leaves to prevent rainwater getting in
Tree beating - A white cloth is placed under a tree and the tree is shaken or beaten to dislodge insects

Question 16

What is the difference between point and frame quadrats?

Answer 16

A point quadrat has a horizontal bar with vertical pins going through which can be pushed down and the species of plant the pin touches is recorded. A frame quadrat is a square frame divided into sections. The type and number of species within each section is recorded.

Question 17

How do you measure species richness?

Answer 17

After sampling, compile a list of each species identified. The total number of species can then be calculated.

Question 18

How to use a quadrat to measure diversity.

Answer 18

Density - absolute measure. Count the number of individual large plants of a species within a 1m by 1m section of the quadrat.
Frequency - estimate. Count the number of squares a species is present in.
Percentage cover - estimate by eye the percentage of the quadrat a certain species occupies.

Question 19

How to calculate biodiversity.

Answer 19

Simpsons index = 1- sum of (n/N)^2

where n = total number of organisms of a particular species
N = total number of organisms of all species

Question 20

What do the results of simpsons index mean?

Answer 20

A value closer to 0 means no diversity and a value closer to 1 means infinite diversity

Question 21

Name some factors that positively effect genetic biodiversity.

Answer 21

• Mutations in the DNA of some organisms creating new alleles.
• Interbreeding between different populations

Question 22

Name some factors that negatively effect genetic biodiversity.

Answer 22

• selective breeding e.g pedigree dogs or human food crops
• captive breeding programmes
• artificial cloning
• natural selection
• genetic bottlenecks - where few individuals within a population survive an event reducing the gene pool

Question 23

What influence can humans have on biodiversity?

Answer 23

Due to population growth humans do many things that negatively impact biodiversity:
- Deforestation = reduces species diversity especially if only one type of tree is being targeted. Reduces the number of animal species around as it destroys habitats
- Agriculture = removal of hedgerows reduces number of plant species present and removes some habitats reducing the number of animals. Pesticides reduce species diversity by killing pests. MONOCULTURE = only planting one crop greatly reduces biodiversity with other plants and also animals.
- Climate Change = melting of polar ice caps could lead to extinction of some of the species that live there. It could also lead to rising sea levels which will flood the low lying land reducing the biodiversity.

Question 24

What does polymorphic mean?

Answer 24

Multiple alleles exist for one gene.

Question 25

What does monomorphic mean?

Answer 25

One allele exists for each gene.

Question 26

What does “loci of a gene” mean?

Answer 26

Position of a gene on a chromosome

Question 27

How to calculate the proportion of polymorphic gene loci.

Answer 27

number of polymorphic gene loci/ total number of gene loci

Question 28

Why should we maintain biodiversity?

Answer 28

Aesthetic reasons - nature enriches peoples lives
Economic reasons - some species may become extinct before they are discovered and they may have the potential to become economically helpful e.g. useful medically. Soil erosion may occur as a result of deforestation.
Ecological reasons - all species are interdependent on each other. Harm of the keystone species can greatly impact the entire ecosystem.

Question 29

What does in situ conservation mean?

Answer 29

Conservation within the natural habitat

Question 30

What does ex situ conservation mean?

Answer 30

Out of the natural habitat

Question 31

Explain some methods of in situ conservation.

Answer 31

Wildlife reserves - restricting human access, controlling poaching, controlling grazing, feeding animals
Marine conservation - create areas of refuge in which populations can build up and repopulate adjacent areas.

Question 32

Explain some methods of ex situ conservation.

Answer 32

Botanic gardens - species are managed to provide them with the resources they need to survive.
Seed Bank - seeds are stored dry and at -20 degrees c to maintain their viability so that they can be used in the future to repopulate if the species goes extinct