Evolutionary mechanisms part 1

Question 1

evolution

Answer 1

change in allele frequencies over time

Question 2

evidence of evolutionary change

Answer 2

geology, biogeography, comparative studies of morphology, embryology, and genetics

Question 3

geology

Answer 3

-fossil records documents continuity in morphological characteristics- evidence of ongoing change in biological lineages

Question 4

biogeography

Answer 4

-distribution of plants and animals in relation to history of landforms, mountain ranges, and oceans is consistent with evolutionary processes

Question 5

comparative emrbyology

Answer 5

• early embryos of related species are similar
• reflect common ancestry
• morphological differences appear as embryos develop

Question 6

comparative morphology

Answer 6

• homologous structures
• reflects common ancestry
• similar embryonic origins, but may have different functions
  
  • human forearm, bat wing

Question 7

comparative genetics

Answer 7

-comparison of DNA sequences of extant and extinct organisms to address questions about evolutionary relationships

Question 8

are african or asian elephants more closely related to the extinct wooly mammoth?

Answer 8

asian elephants

-mammoth DNA more similar to asian elephants

Question 9

mutation

Answer 9

-production of new alleles

Question 10

rearrangement of existing alleles into new combination via:

Answer 10

sexual reproduction

Question 11

true or false: more generations= more mutations

Answer 11

true

Question 12

deleterious mutations

Answer 12

• alter an individual’s structure, function, or behavior in harmful ways
• some are lethal

Question 13

advantageous mutations

Answer 13

-confer a beneit on individuals that carry it- may increase in frequency

Question 14

neutral mutations

Answer 14

neither harmful nor helpful

Question 15

do mutations happen because an individual/ species/ population “needs” them to deal with some specific problem?

Answer 15

no! mutations arise randomly with respects to needs

Question 16

does sexual selection generate new alleles?

Answer 16

no! but it generates new combos of alleles through crossing over and random fertilization

Question 17

quantitative variation

Answer 17

traits that vary along a continuum

-height

Question 18

qualitative variation

Answer 18

either you have the trait or you dont

Question 19

hardy weinberg principle

Answer 19

• model that specifies conditions in which allele frequencies would NOT change and a population would be at genetic equilibrium
• it specifies the conditions in which evolution would not occur

Question 20

genetic equilibrium is possible only if all of the following conditions are met in a population

Answer 20

• no mutations are occurring
• the population is closed to migration
• the population is infinite in size
• all genotypes survive and reproduce equally well
• individuals mate randomly with respect to genotype
• natural populations never meet all 5 requirements

Question 21

relative fitness

Answer 21

number of surviving offspring that an individual produces compared with others in the population

Question 22

examples of evolution by natural selection

Answer 22

• pesticide (mosquitoes and DDT)

- coat coloration in oldfield mice

Question 23

gene pool

Answer 23

all the genes, or genetic information in any population

Question 24

product

Answer 24

an adaptive trait is any product of natural selection that increases the relative fitness of an organism in its environment

Question 25

process

Answer 25

adaptation is the accumulation of adaptive traits over time

Question 26

adaptation s come in 2 general forms

Answer 26

physical and behavioral

Question 27

physical adaptation

Answer 27

camouflage, hair, large ears, flashy plumage

Question 28

behavior adaptation

Answer 28

group living, migration, hibernation, brood parasitism, defensive posture

Question 29

directional selection

Answer 29

occurs when individuals near one end of phenotypic distribution are favored -shifts mean value for the trait away from the existing mean and toward the favored extreme

Question 30

stabilizing selection

Answer 30

occurs when individuals expressing intermediate phenotypes are favored- it eliminates phenotypic extremes -reduces variation, but does not change the mean value of a trait

Question 31

disruptive selection

Answer 31

favors extreme phenotypes over intermediate phenotypes - ex. small and large beak size in black bellied seed crackers - alleles producing extreme phenotypes become more common, promoting discrete traits

Question 32

why doesn't natural selection produce perfect organisms?

Answer 32

- can only act on existing variation in a population - has to work within the bounds of universal physical and chemical constraints - any adaptations usually require compromises (tradeoffs) among different traits

Question 33

natural selection acts on ____ of _____, but ______ is change in allele frequencies (______)in a _______ over time

Answer 33

phenotypes, individuals, evolution, genotypes, population