Evolution 1 Flashcards
a group of individuals that are capable of sharing alleles with one another through reproduction.
species
consist of all the alleles of all genes present in the species
gene pool
the study of the genetic variation in natural populations, which are interbreeding groups of organisms of the same species living in the same geographical area.
Population genetics
Variation in gene pools come from:
independent assortment, crossing over, chance fertilization, rearrangement, mutations
states that sexual reproduction does not reduce genetic variation generation after generation and remains constant if there are no disturbing forces
Hardy-Weinberg Equilibrium
The HWE requires the following assumptions to be met:
- The population size must be large
- Individuals cannot migrate into or out of the population
- Mutation, selection, and migration are negligible
the rate at which a specific allele appears within a population
allele frequency (or gene frequency)
usually seen as the change in characteristics of a population
Evolution
a change in the frequency of an allele in a population
Evolution
the change in frequency of an existing gene variant in the population due to random chance
Genetic drift
results in the elimination of a large portion of the population’s genome
Bottleneck effect
a small representative of the genetic diversity of a population establishes new, reproductively isolated populations
founder effect
four mechanisms of evolution
- Genetic drift
- Gene flow
- Mutation
- Natural selection
any movement of individuals and the genetic material they carry from one population to another
Gene flow
the change in the DNA sequence of an organism. It generates the genetic variation on which the evolutionary process depends
Mutation
It can alter the population’s genetic makeup
Natural selection
This occurs when a single phenotype is favored, causing the allele frequency to continuously shift in one direction
Directional selection
when natural selection selects for two or more distinct phenotypes that each have their advantages
Disruptive selection
It happens when the population stabilizes on a particular non-extreme trait
Stabilizing selection
a mechanism of evolution in which the members of one biological sex choose mates of the other sex and compete with the members of the same sex for access to members of the opposite sex
Sexual selection
a group of interbreeding organisms
species
in cases wherein there is limited or unavailable data on reproductive behavior (such as in fossils)
Morphological species concept
species are groups of interbreeding natural populations that are reproductively isolated from other such groups
Biological species concept
It’s essential in speciation; individuals of different species may not mate with each other, their mating may not produce offspring, or the offspring produces may not be viable or fertile.
Reproductive isolation
focuses on how species interact with their environment and with each other
Ecological species concept
this defines species as the smallest group of organisms that share a common ancestor and possess derived traits or synapomorphies that distinguish them from other groups
Phylogenetic species concept
