Doversity

Question 1

Genetic diversity scaffold

Answer 1

-random mutations -variation of alleles
-some alleles have a selective advantage
-those without adv die and can’t reproduce
-more with adv alleles in pop as allele freq increases

Question 2

Agriculture

Answer 2

Natural ecosystem - from complex community
Agriculture - controlled + selected more productive crops - lower allele freq

Question 3

Economy

Answer 3

Crop yield must be large- little room for anything else

Any one area can only support a certain amount of biomass

Question 4

Chemicals

Answer 4

Pesticides and man made fertiliser further disadvantages and excludes unwanted species
Eutrophication

Question 5

Destruction of hedgerows

Answer 5

Reduces diversity
A shape accommodates lots of species

Question 6

Biodiversity

Answer 6

Number and variety of living organisms in the living world often measured in a particular area

Question 7

Biodiversity importance

Answer 7

Boosts ecosystems productivity
Natural sustainability
Better withstands and recovers from disasters

Question 8

How are organisms classified

Answer 8

Taxonomy
Classifying living organisms naming and group assigning based on similarities and differences

Question 9

Phylogeny

Answer 9

• evolutionary history of relationships between groups of organisms
  -more sophisticated than simple hierarchies
• biochemical genetic evidence based
• shows ancestry and points of divergence from a common ancestor

Question 10

Hierarchy

Answer 10

Groups are subdivided into smaller groups that don’t overlap
Groups go from big to small

Question 11

Population

Answer 11

A group of organisms of the same species that occupy the same place at the same time

Question 12

Genetic drift

Answer 12

The change in allele frequencies of a gene pool due to chance events (they happen randomly by mutations across generations)

Question 13

Gene pool

Answer 13

The collection of genes within an interbreeding population at a particular time

Question 14

Gene flow

Answer 14

Movement of genes from one population to another

Question 15

The founder effect

Answer 15

2) The founder effect describes what happens when just a few organisms from a population start a new colony.
It can lead to an increased incidence of genetic disease because only a small number of organisms have contributed to the gene pool, so there are only a small number of alleles present in the population. There’s more inbreeding in the new population, which can lead to a higher incidence of genetic diseas

Question 16

Non random mating - interbreeding

Answer 16

Non-random mating occurs when there is a bias for or against mating with related individuals.

Inbreeding is preferential mating with relatives.
Inbreeding is a common form of non-random mating.
Inbreeding increases the frequency of homozygosity relative to random mating, elevating the frequency of recessive genetic disorders.

Question 17

Selectional pressure

Answer 17

an environmental force which can alter the frequency of alleles in a population

• Directional
• Stabilising
• Disruptive (less common, more complex)

Question 18

Directional selection

Answer 18

• If e.g an environment changes.
• The ‘selection pressure’ will be exerted
on a particular portion of the population.

Question 19

Stabilising selection

Answer 19

• When a both ends of the population are selected against

Question 20

Disruptive selection

Answer 20

Selection pressure is on the MEAN of the population.

Question 21

Causes of variation

Answer 21

• Mutations
• Meiosis
•
-Crossing over / recombination • -Independent assortment
• Random fertilisation of gametes

Question 22

Continuous Variation

Answer 22

• No distinct catagones
• Tends to be quantitative
• Controlled by a lot of genes
•Strongly influenced by the environment

Question 23

Discontinuous Variation

Answer 23

• Distinct catagories
• Tends to be qualitative
• Controlled by a few genes
• Unaffected by the environment