lecture 3: population and evolution

Question 1

How is variation caused

Answer 1

Variation (caused by random mutations) resulting in new alleles
These may be “advantageous” for survival (survival of the fittest)
The new better adapted organism then has more chance of survival in competition and can reproduce
Passing these advantageous characteristics on to the next generation

Question 2

genetic diversity

Answer 2

Genetic diversity is the number of different alleles of genes in a species or population.
Large number of alleles in a population means a large variety of different characteristics

Question 3

Large amount of different alleles = high genetic diversity

Answer 3

Genetic diversity is a factor enabling natural selection to occur.
Random mutations in the DNA can result in new alleles of a gene.
Many mutations are harmful but, in certain environments, the new allele of a gene might be beneficial leading to increased reproductive success
Gene flow/migration can also increase genetic diversity (alleles being introduced through migration)

Question 4

Adaptations

Answer 4

Natural selection leads to organisms becoming better adapted to their environment.
Features that help organisms to survive
Behavioural
Physiological
Anatomical

Question 5

Genetic bottlenecks

Answer 5

an event that causes a big reduction in a population
e.g. organisms within a population die before reproducing this reduces the number of alleles in the gene pool, so reduces genetic diversity

Question 6

The founder effect

Answer 6

This happens when just a few organisms from a population start a new colony and there are only a small number of different alleles in the initial gene pool.