bio unit 7 Flashcards
(24 cards)
evolution
the change in genetic makeup of a population over time and is supported by multiple lines of evidence
natural selection
the process by which organisms, having adaptations suited for a certain environment, have a greater chance of survival and Reproduction, thereby passing the adaptations to future generations
charles darwin
developed the theory of natural selection
genetic variability
genotypic and phenotypic variations of individuals in a population
genetic differences among organisms within a population
peppered moths
ex. of selective pressure due to environmental change
moths near factory were dark due to air pollution to camo, but once clean air act was passed, they turned white again
competition
organisms have to fight with other organisms for limited resources
adaptations
traits that provide an advantage in a particular environment
fitness
the ability of an organism to survive and produce fertile offspring
reproductive success
the production of offspring by organisms
*repeated reproductive success helps evolutionary fitness
heritability
the ability to pass on adaptations to following generations
selective pressures
any biotic or abiotic factors influencing survivability
ex. disease, predation, climate, food availability
artificial selection
the process by which humans select desirable traits in other species, and selectively bread individuals with those traits
ex. dog breeding
convergent evolution
the process by which similar environmental conditions select for similar traits in different populations/species over time
analogous structures
similar traits observed in distantly related or unrelated species
genetic drift
random change in a particular allele frequency within a population
bottleneck effect
a rapid decrease in population size due to a natural event, resulting in a decrease
conditions needed for hardy weinburg equilibrium
- large population with NO genetic drift
- NO Gene Flow- absence of migration
- no net mutation - no genes are modified, deleted, or duplicated
- Random mating - No sexual selection
- absence of selection - NO natural selection
hardy-weinburg equilibrium
a model for describing and predicting allele frequency in a nonevolving population
means- frequency of alleles and genotypes stays the same generation after generation
h+w equation #1
p²+2pq+q²=1
p²= freq. of homo. dom. genotype
2pq=freq of homozygous genotype
q²=freq. of homo. rec. genotype
h+w equation #2
p + q = 1
p=freq. of dom allele
q=freq. of rec. allele
hardy-weinburg disruptors
- mutations
- non-random mating
- gene flow (migration)
- genetic drift (bottleneck or founder effect)
- natural selection
gene flow
the flow of different genetic makeups in and out of a population due to migration of animals
founder effect
a reduction in genetic variability that occurs when a small group of individuals becomes separated by a larger population
evidence of common ancestry
membrane-bound organelles, linear chromosomes, genes that contain introns
