history of life vocab

relative frequency

number of times an allele occurs in a gene pool compared with the number of times other alleles occur

galapagos

the name of the islands that influenced darwin the most

founder effect

a situation in which allele frequencies change as a result of the migration of a small subgroup of a population

artificial selection

nature provides the variation and humans select those variations that they find useful

genetic drift

random change in allele frequency

mutations

one of the main sources of genetic variation

lyell

a scientist who stated that the processes that changes the earth in the past are the same processes that operate in the present

natural selection

survival of the fittest

thoery

a well-supported, testable explanation of phenomena that have occurred in the natural world

lamarck

scientist who proposed that organisms can acquire traits and pass those traits to their offspring

fitness

ability of an organism to survive and reproduce

disruptive selection

type of selection that occurs when individuals at the upper or lower ends of the curve have higher fitness than individuals near the middlep

fossils

preserved remains of ancient organisms

directional selection

type of selection that occurs when individuals at one end of the curve have higher fitness than individuals near the middle

temporal isolation

type of isolation when species reproduce at different times

reproductive isolation

a type of isolation when species reproduce at different times

descent with modification

principle that states that each living species has descended, with changes, from other species over time

population

the smallest biological unit that can evolve

adaptation

any inherited characteristic that increases an organism’s chance of survival

evolution

change over time; the process by which modern organisms have descended from ancient organisms

gene pool

all the genes that are present in a population

homologous structure

structures that have different mature forms but develop from the same embryonic tissue

struggle for existence

species compete to obtain food, living space, and other necessities of life

behavioral isolation

a type of isolation that occurs when two populations have differences in rituals, and therefore do not interbreed

geographic isolation

a type of isolation when two populations are separated by geographic barriers

vestigial organs

an organ that is present in an organism but serves no useful function

malthus

stated that if human population continued to grow unchecked, there would be insufficient living space or food for everyone

hutton

a scientist who proposed that over millions of years geological forces shaped the earth

genetic equilibrium

a situation in which allele frequencies remain constant

polygenic

traits controlled by two or more genes

stabilizing selection

type of selection that occurs when individuals near the center of a curve have higher fitness than those at either end

recombination

a source of genetic variation (occurs during production of gametes)