Chapter 5

Question 1

What does structure and function reflect?

Answer 1

adaptation of organism to the environment

Question 2

What is natural selection?

Answer 2

differential success of individuals within the population that results from their interaction with their environment

Question 3

What are the three rules of natural selection?

Answer 3

1) there is variation
2) it is heritable
3) provides differences in survival and reproduction

Question 4

What is fitness?

Answer 4

proportionate contribution it makes to future generations

Question 5

What is evolution?

Answer 5

change over time in a population

Question 6

What is an adaptation?

Answer 6

heritable trait that evolved over a period of time to increase fitness

Question 7

What is a gene?

Answer 7

stretch of DNA coding for a functional product (messenger RNA)

Question 8

What is an allele?

Answer 8

alternate forms of a gene

Question 9

What is a genome?

Answer 9

collective DNA in a cell

Question 10

What is a chromosome?

Answer 10

arrangement of genes on a thread

Question 11

What is a locus?

Answer 11

position of a gene on a chromosome

Question 12

What makes a diploid?

Answer 12

at any loci, a diploid has two copies of a gene

Question 13

What are homologous chromosomes?

Answer 13

two copies of a chromosome

Question 14

What is a genotype?

Answer 14

pair of alleles at a given locus

Question 15

What is a phenotype?

Answer 15

external, observable expression of the genotype

Question 16

What is incomplete dominance?

Answer 16

each allele has a specific value that it contributes to the phenotype

Question 17

What are qualitative traits?

Answer 17

phenotypes that fall into a limited number of discrete categories, like color of hair

Question 18

What is a quantitative trait?

Answer 18

phenotypic trait has a continuous distribution, like height or weight

Question 19

What causes quantitative traits?

Answer 19

caused by multiple gene loci or environment

Question 20

What is phenotypic plasticity?

Answer 20

the ability of a genotype to give rise to different phenotypic expressions under different environmental conditions

Question 21

What is an example of phenotypic plasticity in plants?

Answer 21

plant size, reproductive to vegetative tissue ratio, and leaf shape is affected by nutrition, light, moisture, and temperature

Question 22

What is norm of reaction?

Answer 22

set of phenotypes expressed by a single genotype across a range of environmental conditions

Question 23

What is an example of norm of reaction?

Answer 23

insect bodies changing color in response to temperature during development- development in cold makes a darker color, allowing them to absorb light more

Question 24

What is developmental palsticity?

Answer 24

different in phenotype due to differing environmental factors; irriversible

Question 25

What is acclimation?

Answer 25

reversible plasticity, like tolerance to seasonal temperature change

Question 26

What is genetic differentiation?

Answer 26

genetic variation among subpopulations of the same species

Question 27

What is a gene pool?

Answer 27

sum of genetic information across all individuals in the population; total genetic variation within a population

Question 28

How can a gene pool be quantified?

Answer 28

either allele frequency or genotype frequency

Question 29

What is target of selection?

Answer 29

phenotypic trait that selection acts directly upon

Question 30

What is a selective agent?

Answer 30

environmental cause of fitness differences among organisms with different phenotypes

Question 31

What is directional selection?

Answer 31

trait is shifted towards one extreme

Question 32

What is stabilizing selection?

Answer 32

natural selection favors mean at the expense of the two extremes

Question 33

What is disruptive selection?

Answer 33

natural selection favoring both extremes

Question 34

What is the only process leading to adaptation, and why?

Answer 34

natural selection is the only process leading to adaptation because it is the only one that changes allele frequencies

Question 35

What is a mutation?

Answer 35

heritable changes in a gene or chromosome

Question 36

What is genetic drift?

Answer 36

change in allele frequency of a population due to random chance

Question 37

What is an example of genetic drift?

Answer 37

if a parent has few offsprings, not all the genes may be past on and will get lost

Question 38

What is migration?

Answer 38

movement of individuals between local populations

Question 39

What is gene flow?

Answer 39

movement of genes between population

Question 40

What is the Hardy-Weinberg principle?

Answer 40

requency of alleles and genotypes in a population remains constant; no evolutionary change occurs during sexual reproduction itself

Question 41

What are the 5 rules for the Hardy-Weinberg principle?

Answer 41

1) no natural selection 2) no mutation 3) no genetic drift 4) no migration 5) requires random mating

Question 42

What is assortative mating?

Answer 42

when individuals choose mating based on some phenotypic trait

Question 43

What is an example of assortative mating?

Answer 43

female mate choice- when females exhibit a bias toward certain males based on specific phenotypic traits

Question 44

What is positive assortative mating?

Answer 44

mates are phenotypically more similar to each other than expected by chance

Question 45

What is an example of positive ossortative mating?

Answer 45

having the same flowering time leads to a higher chance of reproduction

Question 46

What does positive assortative mating lead to?

Answer 46

increase in homozygotes and a decrease in heterozygotes

Question 47

What is negative assortative mating?

Answer 47

mating occurs when mates are phenotypically less similar to each other than expected by chance

Question 48

What does negative assortative mating lead to?

Answer 48

increases heterozygote frequency

Question 49

What is inbreeding?

Answer 49

mating of individuals more closely related than by random chance

Question 50

What does inbreeding lead to?

Answer 50

inbreeding depression- increased honozygosity at all loci

Question 51

What is a cline?

Answer 51

measurable, gradual change over a geographic region in the average of some phenotypic character, like size or color

Question 52

How can you differentiate plasticity from genotypic variation?

Answer 52

if all individuals in a population share the same phenotype in a controlled environment, it is plasticity; aka a common-garden experiment

Question 53

What is an ecotype?

Answer 53

population adapted to its unique local environmental conditions

Question 54

What are zones of hybridizaition?

Answer 54

areas between ecotypes due to gene flow

Question 55

What is geographic isolate?

Answer 55

extrinsic barrier prevents gene flow among subpopulations

Question 56

What does geographic isolation lead to?

Answer 56

subspecies with a physical geographic line

Question 57

What does natural selection favor?

Answer 57

different phenotypes under different environmental conditions

Question 58

How can fitness act as a trade-off?

Answer 58

maximizing fitness under one set of environmental conditions limits its fitness under different conditions

Question 59

What is adaptive radiation?

Answer 59

process in which one species gives rise to multiple species that exploit different features of the environment