Study Guide Chapter 13 #3

Question 1

struggle for existence

Answer 1

all living things are engaged in what charles darwin called a ……, involves phsyical traits

Question 2

natural selection

Answer 2

may be sruvival of fittest but fitness is more than simply brute strengthes

Question 3

fitness

Answer 3

relative contribution that an individual makes to gene pool of next generation

Question 4

phenotype

Answer 4

exposed to envrionement NOT GENOTYPE

Question 5

diploid

Answer 5

each individaul has two sets of chromosomes and two genes for each character

Question 6

genetic variation

Answer 6

hidden alleles consititue a reserve of genetic varion, keeping gene pool from becoming too reform

Question 7

balancing selection

Answer 7

possible for natrual selecction to maintain both alleles in gene pool,

Question 8

heterozygous advnatage

Answer 8

main yellow allele in gene pool heterozygous red flowers coudl have some advantage over both homozygous red and yello forms - improved diseased resistance

Question 9

frequency dependent selection

Answer 9

type of balancing selection, maintains two different phenotypic forms in population by selecting aginst either form if it become too common,

Question 10

netural variation

Answer 10

much of genetic variation in population probably has little or no impact reproductive success

Question 11

sexual dimophosim

Answer 11

natural selection often shapes differences in appearance

Question 12

seconardy sexual characteristics

Answer 12

might be used in fighting over females

Question 13

intrasexual selection

Answer 13

invovles mate choice, seconardy sexual characteristiics might be used to fight over females

Question 14

males

Answer 14

display their bright plumage

Question 15

females

Answer 15

do choosing

Question 16

good genes hypothesis

Answer 16

a long tail, or loud mating call might reflect overall male health

Question 17

natrual can act

Answer 17

three different ways in which natural selection can act on variation in a poplulation

Question 18

characteristics

Answer 18

such as height vary continuously and can be describd by a bele shaped curve

Question 19

stabilizing selection

Answer 19

kind fo natural selection, favors intermediate variants, not too tall and not too short

Question 20

directional selecction

Answer 20

tyep of natural selection, might favor those individuals geneticaly programmed to grow deepest roots, most common during periods of envrionement change

Question 21

diversing selection

Answer 21

occurs when two different sets of enviornmental conditions favor extreme phenotypes and act against interpedent types

Question 22

natural selection

Answer 22

can only act on exisiting variations which depend on history and chance

Question 23

adaptions

Answer 23

often compromises

Question 24

examples of stabiliing selection

Answer 24

few very short platns in popuatiion and majority of plants of medium heights and few very tall plants, imagine our wildflowers gowing in cold windy environment and very tall plants might freeze before their seeds mature, shorter plants would stay warmer, but very short plants might have troulbe dispering their seeds ot favorable envrionment, STABILIZING SELECTION FAVORS INTERMEIDATE VARIANTS NOT TOO TALL NOT TOO SHORT

Question 25

example of directional selection

Answer 25

environemnt is gradually becoming drier, DIRECTIONAL SELECTION MIGHT FAVOR THOSE INDIVIDUALS GENETICALLY PROGRAMMED TO GROW THE DEEPEST ROOTS

Question 26

example of diviersing selection

Answer 26

(ample, plants with shallow, spreading roots might be an advtange in dry s=rocky soil where water tends to penetrate quicly and deep taproot system might be gavored in richer soul that hodls water longer, intermate root systems would be at disadtanvte in both enviornemtns)