Selection Flashcards
when does selection occur?
When genotypes differ in their ability to pass genes on to the next generation
What is artificial selection?
Human modification of species over many generations by selecting and breeding individuals that possess desirable traits
What is natural selection?
Differential survival and reproduction of individuals due to differences in phenotype
What is sexual selection?
A form of selection in which individuals with certain inherited characters are more likely than other individuals to obtain mates
What is adaptation?
evolutionary change that fits an animal to its habit or habitat
How can you recognise adaptation?
Optimality - evaluation of costs and benefits of different features
Comparisons of organisms with similar lifestyles
Experimental
What are there mechanisms that produce evolutionary change?
Genetic drift, mutation, meiotic drive, molecular drive which bring about variation, however the change is random, adaptation is directional. Selection
How does selection drive evolution?
Better adapted individuals survive longer and mate more frequently, so leave more offspring. Poorly adapted die earlier and traits are passed on to fewer or none.
What factors are required for selection to occur?
Multiplication, leads to struggle for existence
Variation + struggle for existence leads to differential survival and reproduction (selection)
How do selection and inheritance lead to adaptation?
Traits are passed down to offspring, variation of individuals and multiplication leading to selection means that adaption will occur as the fittest individuals survive
What is a discontinuous character?
determined by one set of genes
What is a continuous character?
Determined by multiple sets of genes - polygenic, more complex characters
How does new variation arise?
Recombination and mutation
How does mutation drive adaptation?
Mutation creates variation, which is random in direction, Selection for the variations provides direction to adaptive change
What is the ultimate source of variation?
Mutation
