Unit 7: Natural Selection Unknown Info (AP Biology 2026) Flashcards

the change in the gene pool of a POPULATION over time

the driving force of evolution and operates on the INDIVIDUAL

18th century, On the Origin of Species, finches

pre-Darwin WRONG theories that acquired changes show up in gametes

the study of fossils

age of rocks around a fossil, rate of decay of isotopes, geographical data

study of distribution of flora and fauna in the environment

the study of development of an organism

the study of the anatomy (homologous and analogous structures) of various animals

same appendages that develop different purposes, point to common ancestor

features with the same function but different structures, evolved independently (e.g. insect and bat wings)

closely related organisms have a greater proportion of nucleotide / amino acid sequences in common

evolution is constantly occurring with consistent small changes in DNA, fossil record, evolving pathogens

some original life form shared between two groups

hypotheses used to study relationship between organisms

the least related group to all other species in a phylogenetic tree

no two individuals in a population have an identical set of alleles

example of directional selection, air pollution, black becomes prevalent over white

a variation favored by natural selection

internal advantage, initial variation is by chance but can eventually become an advantage only after something makes it apparent

external sources causes a trait to be advantageous

given to an organism with ANY trait that causes it to reproduce better

natural selection arising through preference of some trait that makes an individual more likely to be chosen for reproduction

something that causes a change in a population that is not natural selection (left over traits RANDOM, not necessarily advantageous)

genetic drift, random events that drastically reduce the number of individuals in a population

occurs between different populations of the same species with immigration or emigration of populations

one phenotype is favored at one extreme of the normal distribution

organisms in a population with extreme traits are eliminated (middle is favored)

favors both extremes and selects against common traits

humans directly affect variation in other species

two individuals able to mate and produce viable offspring that would be able to mate and produce viable offspring

two species who cannot mate, allowing them to undergo natural selection and evolve differently

when different variation and environmental pressures cause a change that makes groups no longer able to mate

divergent evolution occurs quickly after a period of little evolution (stasis)

divergent evolution that comes after many small changes over hundreds or millions of years

divergent evolution when a species rapidly diversifies due to an abundance of available ecological niches

fertilization is prevented between two species

inability of hybrid organisms to produce offspring

two unrelated and dissimilar species come to have analogous traits, because exposed to similar selective pressures

the formation of new and distinct species in the course of evolution

a population becomes separated from the rest by a geographic barrier, so the two can't interbreed

new species form without a geographic barrier

possessing more than two complete sets of chromosomes (plants)

even with all the shuffling of genes, the relative frequencies of genotypes in a population are constant over time (neither dominant nor recessive disappears)

large population, no net mutations, no immigration or emigration (no gene flow), random mating (no sexual selection), no natural selection

dominant allele frequency

recessive allele frequency

homozygous dominant genotype frequency

heterozygous genotype frequency

homozygous recessive genotype frequency

primitive atmosphere of Earth contained mostly inorganic molecules, rich in gases with almost no free oxygen, gas collisions and chemical reactions led to organic molecules of today

proved Oparin and Haldane in lab with gases in a flask, charged, created organic compounds similar to amino acids

original life forms were simply molecules of RNA that could replicate and pass their genome along