Chapter 13: Natural selection and mircoevolution Flashcards
What is the definition of a gene pool?
The range of genes and all their alleles present in a population
What is the three main processes which cause microevolutionary changes?
Mutations, gene flow and genetic drift.
What is gene flow?
The transfer of alleles that result in emigration and immigration of individuals from populations
How do gene flow and migration affect microevolutionary changes?
They remove or add alleles which can change the frequency of others
What is genetic drift?
The random changes in small populations, the loss of alleles
How does genetic drift affect microevolutionary changes?
Alleles are easy to lose but are virtually impossible to replace. Can cause the bottleneck effect or founder effect
What is the bottleneck effect?
With a reduction in the population, alleles are lost and the gene pool can only carry alleles the population has now.
What is the founder effect?
A population that moves and becomes isolated will not carry all the alleles present in the larger population and therefore be less genetically diverse.
What is one possible outcome of the founder effect?
Recessive genes are more likely to appear due to the reduced allele population
Is allele frequency positive or negative?
It can be either depending on the situation and frequency which occur
What is viability?
Capability of living
What is fecundity?
Measure of fertility
What is natural selection?
A selection mechanism that acts on phenotypes suited for their environment. It can lead to adaptive evolution
What is adaptive evolution?
Changes in population of organisms that make a population better suited for its environment over time, only occur if there is a variation of heritable trains
What are the selection pressures of natural selection?
Competition for food or territories between species or within species, predators, nesting places, sexual selection
