Genetic Diversity Flashcards
(23 cards)
What is genetic diversity
The number of different alleles of genes in a species or population
What is a population
A group of organisms of 1 species living in a particular habitat at a certain time
How is genetic diversity increased
Mutations in dna
Migration
How does dna mutations increase genetic diversity
Forms new alleles
How does migration increase genetic diversity
Different alleles are introduced into the population and reproduction circulates the allele
= gene flow
What is a genetic bottleneck
An event that causes a big reduction in the population
Reducing the number of alleles in the gene pool
Reducing genetic diversity
Survivors reproduce from a smaller gene pool
What is a gene pool
The complete range of alleles in a population
What is the founder effect
A few organisms from a population start a new colony
There are only a few number of different alleles in the initial gene pool
So the allele frequency in the new population may be different to the initial population
What are the negative impacts of the founder effect
Higher chance of genetic disease
Because there is a higher allele frequency of genetic diseases
Why does the founder effect happen
Migration leading to a geographical separation
Why does a new mutated allele die out
It isn’t beneficial for survival
Explain natural selection
Organisms with an allele which leads to an increase in change survival of survival, reproduce and pass on the beneficial allele
A greater proportion of the next generation inherits the beneficial allele
So are more likely to survive and reproduce
The frequency of the beneficial allele increases
What is evolution
The gradual change in a species over time
What are behavioural adaptions
The ways organisms act that increase its chance of survival and reproduction
Give an example of behavioural adaptions
Playing dead to stop predator attack
What are physiological adaptions
Processes inside an organisms body that increase its chance of survival
Give an example of a physiological adaption
Hibernation to lower metabolic rate and conserve energy
What are anatomical adaptions
Structural features of an organism that increase its chance of survival
Give an example of anatomical adaptions
Blubber for insulation
What is directional selection
Alleles for extreme characteristics are more likely to survive and reproduce
Explain selection in relation to antibiotic resistance
Some organisms in a population will have the allele for antibiotic resistance
The population is exposed to antibiotics
Only the organisms with antibiotics resistance survive and Reproduce
Increasing antibiotic resistance allele frequency
= directional selection
What is stabilising selection
Organisms with alleles for characteristics in the middle range are more likely to survive and reproduce
Why is baby weight an example of stabilising selection
Very small babies = hard to maintain body temp
Bert big = giving birth is difficult
Medium sized babies are more likely to survive
