Biology Chapter Thirteen

Front 1

macroevolution

Back 1

evolutionary change on a frand scale, encompassing the origins of novel kinds of organisms invading new habitats, and major episodes of extinction

Front 2

microevolution

Back 2

gradual changes in a population that include more and more individuals with the advantageous characteristics.

Front 3

adaptation

Back 3

microevolutionary changes that increase the likelihood of survival and reproduction of particular gfenetic traits in a population

Front 4

punctuated equilibrium

Back 4

a long period of no change, until a new spurt of evolutiuon created a punctuation in fossil record

Front 5

gradualism

Back 5

gradual evolutionary change

Front 6

Darwin's theory of natural selection

Back 6

natural selection on variants within populations leads to evolution. viewed over long time periods, some groups evolve at a uniform rate, while others in fits and starts.

Front 7

molecular clocks

Back 7

the changers that appear to accumulate in cytocrome c (a genethat codes for a prodein active in oxidative metabolism) at a constant rate

Front 8

homologous structures

Back 8

although the structure and functino of the bones have diverged, they are still derived from the same body part present in a common ancester.

Front 9

analogus structures

Back 9

features found in different lineages come to resemble each other as a result of parallel evolutionary adaptations to similar environments

Front 10

alleles

Back 10

alternative form of a gene

Front 11

allele frequencies

Back 11

the othe proportiopns of alleles of a given gene

Front 12

Hardy-Weinburg Equilibrium

Back 12

preportions do not change and the genotypes are said to be in equilibrium

Front 13

frequency

Back 13

the proportion of individules falling within a category in relation to the total number of individuals being considered

Front 14

mutation

Back 14

an error in replication of a nucleotide sequence in DNA

Front 15

migration

Back 15

the movement of individuals from one population into another

Front 16

Hardy-Weinburg conditions

Back 16

mutations
migration
genetic drift
nonrandom mating
selection

Front 17

genetic drift

Back 17

random loss of alleles, more likely to occur in smaller populations

Front 18

founder effect

Back 18

if the alleles are rate in the source population, they wil be a significant fraciton of the new populations genetic endowment

Front 19

bottleneck effect

Back 19

if organisms do not move from place to place. there popuilation may be drastically reduced in size. the surviving individuals constitue a random genetic sample of the original population a restriction in genetic variability

Front 20

nonrandom mating

Back 20

individual with certain genotypes mate with one enother either more or less commonly thatn would be expected on a random basis

Front 21

inbreeding

Back 21

mating with relatives; a type of nonrandom breeding

Front 22

selection

Back 22

when some individuals leave behind more progeny than others, and the likilhood they will do so is aftcted by thier inherited characteristics

Front 23

artifical selection

Back 23

the breeder selects the for the desired characteristics

Front 24

natural selection

Back 24

the environment selects for the desired characteristics

Front 25

stabilizing selection

Back 25

when selection acts to eliminate both extremes from an array of phenotypes, the result is an increase in the frequency of the already common intermediate phenotype

Front 26

distruptive slection

Back 26

selection acts to eliminate the intermediate type

Front 27

directional selection

Back 27

when selectin acts to eliminate one extreme from an array of phenotypes, the genes determining this extreme become less frequent in the population

Front 28

sickle cell anemia

Back 28

the hereditary disease affecting the hemoglobin molecules in the blood

Front 29

heterozygote advantage

Back 29

the payoff in the survival of heterozygotes there more makes up for the price in death of heterozygotes

Front 30

speciation

Back 30

the species forming process in many different plants,. animals, and microorganisms

Front 31

biological species concept

Back 31

defines pecies as groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups

Front 32

reproductively isolated

Back 32

populations whose members do not mate with each other or who cannot produce fertile offspring

Front 33

reproductive isolating mechanisms

Back 33

prevent genetic exchange between species

Front 34

prezygotic isolating mechanisms

Back 34

those that prevent the formation of zygotes

Front 35

postzygotic isolating mechanisms

Back 35

those that prevent the proper functioning of zygotes after that have formed

Front 36

prezygotic isolating mechanisms (6)

Back 36

geographic, ecological,temporal,behavioral,mechanical,prevention of gamete fusion

Front 37

allopatric speciation

Back 37

goegraphically separeated, populations appear much more likely to have evolved substantial differences leading to speciation

Front 38

sympatric speciation

Back 38

one species splitting into two at a single localitywithout the new psecies ever having been geographically separated

Front 39

polyploidy

Back 39

instantaneous sympatric speciation occurs when an individual was born that is reproductively isolated from all other members of its species. ocrrurs commonly in plants

Front 40

autopolyploidy

Back 40

all sets of the chromosomes are from the same species

Front 41

allopolyploidy

Back 41

occurs when two species hybridyze