Genetic Diversity and natural selection Flashcards
What is natural selection
Natural selection is the process in which organisms that evolve and adapt to suit their environment better will survive longer and reproduce so they will pass on their genes.
What is the founder effect?
The founder effect is people isolating themselves from other cultures which can lead to a small gene pool and more genetic diseases.
What are behavioural adaptations?
Ways organisms act to increase their chances of survival.
Give an example of a behavioural adaptation?
An example of a behavioural adaptation is the way bears hibernate in winter to conserve energy as the rate of metabolism slows.
What is a genetic bottle-necking?
An event that leads to the reduction in genetic variation of a species. The remaining ones will then reproduce and all future offspring will have similar genes.
What is a chiasma?
A posh word for crossing over in the case of DNA.
What are possible outcomes of the founder effect?
Possible outcome of the founders effect include genetic diseases such as dwarfism, 6 fingers and metal retardation.
What are directional adaptations?
Adaptations causing one certain excessive characteristic. E.g being tall
What are stabilising adaptations?
Stabilising adaptations are adaptations making the organism more stable and ‘average’
What is selective breeding
Selective breeding is breeding of organisms where certain desired characteristics are chosen by humans for the organisms.
Give examples of selective breeding
- breeding dogs to create funny looking ones
- breeding cows to make chungus ones
- breeding plants of a bigger yield
Give two advantages of selective breeding:
- bigger yield
- stop diseases and harmful things
Give two disadvantages of selective breeding:
- small gene pools may be created
- life expectancy is lower for certain animals (cows udders have become so large they cant walk)
What does monogenic mean when referring to genes?
Monogenic means theres only one allele
What does polygenic mean when referring to genes?
Polygenic means theres more than one allele. Polygenic things are generally more adaptable to environmental change
