evolution Flashcards
Allele frequency equation
number of copies of an allele
______
Total #of alleles for the same gene in the population
Evolution
The change in allele frequencies and genetics in a population over time
Allele
A version of a gene that produces a specific trait (B vs. b)
Do individuals evolve?
No, since an individual’s alleles don’t change
Population
Group of organisms of the same species
Natural Selection
Features best suited to an environment are able to survive and reproduce better than others
Habitat
The type of natural environment that a species lives, made up of both physical and biological features
What are some abiotic factors?
Temperature, rainfall, humidity, heat
Fitness
reproductive success
Niche
The role the species takes in that habitat including the precise location and resources used
What does “variation among individuals in a population” mean?
Variation in a trait that impacts an individual’s ability to acquire resources and/or survive in an environment
What does “variation must be heritable” mean?
Variation is passed from parent to offspring
What does “over-production” in natural selection mean?
Each generation, more offspring are produced than can be supported by local resources
What does “differential survival and reproduction” mean?
Individuals possessing traits that increase their success will contribute more offspring to the next generation
What happens when two or more species occupy the same niche?
Competition, forcing the other species to adapt or risk extinction
Explain how natural selection determines who survives to reproduce and who does not
As environmental conditions change, the phenotypes that
natural selection favors will also change
Genetic variation
Within a species, no 2 individuals are exactly alike
Over production of off spring
More individuals are born than survive to reproduce
Unequal reproductive success
The inherited characteristics of some individuals make them more likely to obtain resources, survive, and reproduce
Descent with modification
a population’s characteristics can change by natural selection, even giving rise to new species
Modern evolutionary synthesis
Genetic variation is the raw material on which evolution acts
Adaptation
A genetically-based trait that increases an individuals ability to produce off spring in a particular environment
Mutations
Changes in a DNA nucleotide sequence
Variation
A trait that impacts an individuals ability to acquire resources and for survive in an environment
Directional Selection
The median variation for a trait moves toward one of
the extremes