Studied by 0 people
Looks like no one added any tags here yet for you.
genetic variation
every population has individuals with slightly different traits due to genetic variations arising from mutations, which are the raw material for natural selection to act upon
overproduction of offspring
more offspring than an environment can support leading to competition for resources like food and mates
competition for resources
due to overproduction, individuals must compete for limited resources, creating a “survival of the fittest” environment
differential survival and reproduction
individuals with more favorable traits/phenotypes to their environments are more likely to survive and reproduce, passing on those advantageous traits to their offspring
artificial selection
when humans can modify an organism by selecting desired traits and breeding them; the domestication of dogs from wolves
an example of evolution as an ongoing process in all living organisms
drug resistant bacteria; a population of bacteria continuously adapts to the presence of antibiotics, leading to strains that are increasingly difficult to treat with existing medications
homologous structures
similarities in characteristics from common ancestryf
fossils
transition species, show a succession of organisms over a long period of time
vestigial structures
modern animals may have structures that serve little or no function; human appendix
molecular evidence
comparing DNA and protein structures between organisms because we share the same basic genetic material, genetic code, and mechanisms for gene expression
biogeographical
the geographic distribution of species, species who live closer together (eg; in North America) are more closely related than species who live farther away (eg; North America vs Asia)
convergent evolution
species who look alike, but aren’t closely related. Different species independently evolve similar traits to adapt to similar environments; sharks and dolphins both have streamlined bodies for swimming, but aren’t related at all
the conditions needed for a population to be in Hardy-Weinberg equilibrium
large population size, no mutations, no migration, random mating, and no natural selection
no selection
no traits are more beneficial to survive
no mutation
gene pool stays the same
no migration
no new genes
large population
less chance of flunctuations
random mating
no traits are preferred
genotype frequency
p²+2pq+q²=1
allele frequency
p+q=1
p
frequency of the dominant allele in the populationq
q
frequency of the recessive allele in the population
p²
homozygous dominant individuals in a population
2pq
heterozygous individuals in a population
q²
homozygous recessive individuals in a population
bottleneck effect
a sharp reduction in population size due to environmental events or human activities, leading to a loss of genetic diversity
founders effect
small group starts a new population resulting in reduced genetic variation; amish people
genetic drift
random changes in allele frequency
gene flow
migration
directional selection
favors one extreme trait over others; peppered moths during industrial revolution
stabilizing selection
favors the average trait (human birth weight)
disruptive selection
favors both extremes; light and dark crabs can both hide on light and dark rocks from predators
sexual selection
traits increase reproductive success; male peacocks flash their tails at females to mate
biotic factors on evolution
vegetation, predators, prey
abiotic factors
soil, temperature, climate conditions
stable environments
lower rate of evolution; constant selective pressures
fluctuating environments
higher rate of evolution; new selective pressures
convergent evolution
occurs when unrelated organisms evolve similar traits due to environmental pressures; not artificial selection, but still involves selection pressures shaping traits
speciation
formation of new species
phylogenetic trees
diagrams that show evolutionary relationships among species based on common ancestry
out group
species that is least closely related to others in a phylogenetic tree
shared traits
traits found in multiple species
derived traits
traits inherited from a common ancestor that distinguish groups
biological species concept
a definition of species based on reproductive isolation, where members of a species can interbreed and produce fertile offspring
punctuated equilibrium
rapid bursts of evolution followed by long periods of no change, often occurs after mass extinctions or environmental changesg
gradualism
evolution occurs slowly and steadily over long periods, small genetic changed accumulate, eventually leading to speciation
allopatric speciation
occurs when a physical barrier separates populations; mountains, rivers, islands
sympatric isolation
no physical barriers, occurs within the same geographic area due to disruptive selection and mating preferences
pretzygotic isolation
before fertilization, habiitat, temporal, behavioral, mechanical, gametic isolation
postzygotic isolation
after fertilization; embryo fails to develop or offspring are sterile
Permian-Triassic Extinction ("The Great Dying")
252 MYA, likely due to volcanic eruptions, ocean chemistry changes, and climate shifts, 90% of pop wiped out
Cretaceous - Paleogene Extinction
66 MYA, , asteroid impact, dinosaur extinction allowed mammals to dominate
RNA world hypothesis
RNA was likely the first self replicating molecule; some modern RNA molecules (ribozymes) can act as enzymes
