Genetic diversity and adaptation Flashcards
(12 cards)
What is meant by genetic diversity?
Genetic diversity is the number of different alleles of genes in a population.
What is the importance of genetic diversity?
Genetic Diversity is a factor that enables natural selection to occur. The greater the genetic diversity, the more likely that individuals in a population will survive an environmental change.
How can genetic diversity within a population be increased?
1) Genetic mutation, leading to new alleles.
2) New alleles being introduced into a population when individuals from other populations migrate into them & reproduce with them.
3) Meiosis.
4) Random fertilisation of gametes during sexual reproduction.
How does genetic diversity increase likeliness of survival?
When a population has a wider range of alleles, they have a wider range of characteristics meaning there’s a greater probability that an individual will posses a characteristic that suits it to the new conditions.
What is the process of natural selection?
1) New alleles are formed by random mutations in genetic material.
2) Many mutations are harmful, which may mean that the individual with the mutated allele dies out. Sometimes however, an allele (or combination of alleles) gives an individual an advantage, leading to increased chance of survival and reproductive success.
3) These individuals pass on their advantageous alleles to the next generation.
4) Over many generations, the new allele increases in frequency in the population.
What are the key types of selection?
Directional, stabilising, and disruptive selection.
What is directional selection?
Directional selection is when individuals with alleles for characteristics of an extreme type
are more likely to survive and reproduce (e.g. antibiotic resistance in bacteria).
What is stabilising selection?
Stabilising selection is when individuals with alleles for characteristics towards the middle range are more likely to survive and reproduce (e.g. human birth weight).
What are the types of adaptations that may occur as a result of natural selection?
Behavioural, anatomical, and physiological adaptations.
What are behavioural adaptations?
Behavioural adaptations refer to a change in the way an organism acts that increases its chance of survival.
What are anatomical adaptations?
Anatomical adaptations refer to a change in the features of an animal’s body that increases its chance of survival.
What are physiological adaptations?
Physiological adaptations refer to a change in the process inside an organism’s body that increases its chance of survival.
