Genetic Diversity And Adaptation Flashcards
What is genetic diversity
The number of different alleles of a gene in a population
What two things increase genetic diversity
Mutations in DNA forming new alleles
Different alleles being introduced a population
Genetic diversity is a factor which enables….. to occur
Natural selecting
What is a genetic bottleneck
What is the consequence of this
An event that causes a large reduction in a population
Reduces number of different alleles in gene pool so reduced genetic diversity
Explain the founder effect
When organisms from a population start a colony with a small number of different alleles
This can result in rare alleles becoming more common
What is a behavioural adaptation
The way the organisms acts that increases its chance of survival
What is a physiological adaptations
The processes inside inside an organisms body that increases its chance of survival
What is an anatomical adaptation
These are structural features of an organisms body that increases its chance of survival
What are the two types of natural selection
Directional
Stabilising
What is directional selection
The alleles for characteristics of an extreme type
This occurs when there is a change in the environment
What is natural selection explain
New alleles for a gene are created by random mutations
New alleles can increases survival chance so more likely to reproduce
This advantageous allele will be passed to next generation
Over many generations new allele will increase in frequency
What is stabilising selection
When the modal trait has a selective advantage
Happens when there is no change to the environment
What happens to standard deviation during stabilising selection
Decreases
Why is there a lag time between introduction of X and then the mutation which leads to the resistance of X becoming more common
Initially only a few with favourable mutation
Individual with favourable mutation produce more offspring
Takes many generations of the mutation of this allele to become more common
Describe crossing over x4
Homologous pairs of chronometer
Twist and wrap around each other
EQUAL lengths of alleles are exchanges
Producing new combination of alleles
(NOT GENES)
