Unit Two: Evolution Flashcards
What are the three kinds of mutations?
Substitution, Insertions, Deletion
What is substitution?
The replacement of one base nucleotide with another in DNA
What is insertion?
The addition of one or more bases in DNA sequences
What is deletion?
The removal of one or more bases in DNA sequences
What is a beneficial mutation?
A change that has an advantage in survival or reproduction, increasing their ability to pass on genetic material
What is a neutral mutation?
A change does not create an advantage or disadvantage for reproductive success or survival
What is a harmful mutation?
A change that creates a disadvantage for survival or reproductive success
What is natural selection?
The process by which organisms with traits that increase fitness are more likely to pass these traits to the next generation
What is fitness?
An individuals ability to survive and reproduce
What is allele frequency?
The proportion of individuals in a population carrying the same allele
What is Stabilizing selection?
Natural selection where moderate traits are favored and extremes are selected against
What is directional selection?
Natural selection where an extreme is being selected for and the opposite extreme and moderate are selected against
What is disruptive selection?
Natural selection where both the extremes are favored for and the mean is selected against
What are selection pressures?
Environmental factors that define whether an organism will be more or less successful at surviving and reproducing
What are the three kinds of selection pressures?
Resource availability, environmental factors, biological factors
What is sexual selection?
The selection of traits from the preference one sex has for certain characteristics in individuals of the other sex
What are sexual dimorphisms?
Distinct differences in size, shape, color, or other physical characteristics between males and females of the same species
What is genetic drift?
The change in allele frequency over generations due to random chance (bottleneck and founder effects)
What is gene flow?
Transfer of alleles and genes between different populations of the same species through migration and reproduction, contributing to genetic diversity
What is artificial selection?
Intentional breeding of organisms by humans to promote specific desirable traits or characteristics that have benefit to humans
What is the Hardy-Weinberg equilibrium?
An equation that describes the allele frequencies in a population under ideal conditions when no evolution is occurring
What is the equation for allele frequencies?
P+Q=1
What is the equation for genotype frequencies?
P2+2PQ+Q2=1
What is genetic diversity?
The variety of alleles within a population of a species
Define biological evolution
All species on earth today are descended from ancestral species which have adapted over time
Define species
A group of organisms that can be interbred, produce fertile offspring, share common characteristics
What is speciation?
When populations become reproductivily isolated and diverge, creating new species
What is a reproductive isolating mechanism?
Anything that prevents successful reproduction from occurring
What is micro evolution?
Small scale changes that occur within a population over a relatively short period of time
What is macro evolution?
Large scale changes that occur over long periods of time and result in the formation of new species
What is divergent evolution?
When closely related species evolve to become different, due to different environmental pressures
What is convergent evolution?
When unrelated species develop similar traits independently, due to similar environmental pressures
What is parallel evolution?
When related species evolve in similar ways after diverging from a common ancestor, due to similar environmental pressures
What is co evolution?
When changes in one species drives change in another species
What is gradualism?
When evolution occurs through a slow and continuous accumulation of small changes over long periods of time
What is punctuated equilibrium?
Species often remain relatively stable for long periods of time with rare and rapid bursts of change
What are homologous features?
Traits or characteristics are similar in different species because they share a common evolutionary ancestry
What are vestigial structures?
Features that have reduced in size or function because it is longer necessary for the organisms survival
What are analogous features?
Features in different species that serve similar functions, but they evolved independently
What are the five assumptions that the Hardy-Weinberg equilibrium is based on?
- Large population
- No migration
- No mutation
- Random mating
- No selection
