Genetic Diversity and Adaptation

Question 1

What’s genetic diversity?

Answer 1

• Number of different alleles of a gene in a population

Question 2

Population

Answer 2

Group of interbreeding individuals of the same species

Question 3

The principles of natural selection in the evolution of populations

Answer 3

1) variations of alleles exist in a population due to random DNA mutations e.g. antibiotic resistance

2) selection pressure / change in environment e.g. antibiotic introduced

3) those with advantageous allele have increased chances if special and reproduction e.g. A bacteria with a gene for resistance to survive and reproduce while those without it die.

4) those surviving reproduce and pass on the advantageous allele to the offspring

5) frequency of advantageous, allele characteristic increases in the population

6) over a long period of time

Question 4

Directional selection, e.g. antibiotic resistance

Answer 4

-change to the environment
-Selection, pressure act one side of the mean
-One extreme phenotype, more likely to survive and reproduce

Question 5

Stabilising selection, e.g. human birthweights

Answer 5

• stable environment
• Selection pressure acts, either side of the mean
  -both extremes of phenotype less likely to survive e.g. very small or very large babies

Question 6

What does natural selection result in?

Answer 6

• better adapted species
• these adaptations or increase in organism survival chance
• PHYSIOLOGICAL E.g. structural features whale’s thick layer of blubber helps keep warm in cold sea
• BEHAVIORAL e.g. possum plays dead if they’re being threatened by a predator to escape attack

Question 7

Species

Answer 7

If two organisms belong to the same species, they are able to produce fertile offspring

Offspring from two different species may be infertile because they will have an odd number of chromosomes so meiosis can’t happen

Question 8

Courtship

Answer 8

• allows recognition of members of the same species because courtship behaviour is species specific → production of fertile offspring
• indication of sexual maturity
  -Recognition/attraction of the opposite sex

Question 9

How is a phylogenetic classification system organised?

Answer 9

Arrange a species into groups based on the evolutionary origins and relationships

Question 10

Advances in immunology and gene sequencing to help clarify, evolutionary relationships between organisms

Answer 10

Genome sequencing
- Compare the order of the base sequence
Higher % match → more closely related

Immunology
DNA → mRNA → sequences of amino acids in polypeptide
Tertiary structure of protein tells us the DNA sequence
- If same antibody bind to a specific antigen then is closely related

Question 11

Biodiversity

Answer 11

Variety of organisms living in an area
Has 3 components
- species diversity → the number of different species and number of individuals of each species within a community
-genetic diversity
-ecosystem diversity

Question 12

Habitat

Answer 12

Places where an organism lives

Question 13

Community

Answer 13

All the populations of different species in a habitat

Question 14

Local diversity

Answer 14

The variety of species living in a small habitat e.g. pond

Question 15

Species richness

Answer 15

The number of different species in a community

Question 16

The balance between conservation and farming

Answer 16

Humans need to make a balanced judgement between the demands for increased food production due to rapidly growing human population and need to conserve the environment.

Some conservation techniques can be applied to increase biodiversity
-reduce the use of pesticides
-maintain existing hedge Rose and plant new hedges