2.2 Evolution Flashcards
What is evolution?
Evolution is the change over time in the proportion of individuals in a population differing in one or more inherited traits.
What are the three types of mutations, and how does variation arise in a species?
Advantageous, neutral and deleterious.
Mutation.
Give a brief summary of what natural selection is and the process involved.
Natural selection is a non-random process that acts on variation within a population.
What is sexual dimorphism?
Differences between the sexes.
Describe the two methods through which sexual selection is achieved.
- Male to male rivalry is when larger weaponry or size increases access to females through successful conflict.
- Female choice is when a female assesses fitness based on honest signals.
Describe what is meant by selection pressure and give examples.
A selection pressure measures how much a biotic or abiotic factor influences its environment.
Biotic - predation, competition and disease.
Abiotic - Changes in temperature, pH and light.
Describe genetic drift.
Genetic drift is a random process which occurs when chance events cause fluctuations in allele frequency, from one generation to the next.
Is genetic drift more important in smaller or larger populations?
Smaller.
Describe the bottleneck effect.
The bottleneck effect is when a population size is randomly reduced for at least one generation so lowering the range of alleles any subsequent selection pressures may act.
Describe the founder effect.
The founder effect is when a small portion of the population, not representative of the original gene pool, become isolated.
3 principle that must apply so that the HW equilibrium can apply.
No migration, a large population and no mutations.
Give the HW equation.
p^2+2pq+q^2=1
Describe the conclusion that can be drawn from changes in the HW principle.
There is evolution in the population.
What is meant by fitness?
Fitness is the ability of an individual to survive and reproduce.
Describe the equation to work our absolute fitness.
G2:G1
