biology lec 28-31

Question 1

natural selection

Answer 1

process that results in the adaptation of an organism to its environment by means of selectively reproducing changes in its traits

Question 2

four postulates of natural selection

Answer 2

1. individuals must vary
2. variation must be heritable
3. individuals must vary in fitness
4. surival/reproduction is correlated with variations

Question 3

adaptation

Answer 3

any trait resulting from natural selection

Question 4

variation and mendel

Answer 4

new alleles result from mutations that lead to phenotypic variation within a population

Question 5

heritable and mendel

Answer 5

alleles are passed from parents to offspring through Mendelian genetics

Question 6

natural selection and mendel

Answer 6

most fit individuals are those whose geno/phenotypes best adapt them to their environments

Question 7

microevolution

Answer 7

change in trait of population/species

Question 8

Changes in allelic frequencies

Answer 8

proportion of all alleles in a population

Question 9

mutation

Answer 9

changes in DNA sequence, gene number, gene order, etc = new alleles

Question 10

effects of mutations

Answer 10

many lower fitness
many neutral
few increase fitness

Question 11

how does sexual reproduction affect natural selection

Answer 11

creates new combinations of mutations

Question 12

how is sexual reproduction affect mutations

Answer 12

can eliminate bad mutations
- can produce non-mutants
can combine good mutations
- two good traits can combine in offspring

Question 13

how does asexual reproduction affect mutations

Answer 13

causes mutations to accumulate in population

Question 14

adaptive evolution

Answer 14

phenotypes that improve fitness increase over time

Question 15

directional selection

Answer 15

pushes population toward an extreme phenotypes

Question 16

stabilizing selection

Answer 16

pushes population toward an intermediate phenotype

Question 17

disruptive selection

Answer 17

pushes population away from intermediate phenotype

Question 18

genetic drift

Answer 18

unpredictable, random changes in allelic frequencies (greater effect on small population)

Question 19

genetic bottleneck

Answer 19

results of rapid reduction in population size

Question 20

founder effect

Answer 20

new populations often founded by few individuals

Question 21

gene flow

Answer 21

movements of individuals among populations

Question 22

biological species concept

Answer 22

defines a species as a population of organisms that are capable of interbreeding and have an ancestor-descendant relationships among individuals

Question 23

reproductive isolation

Answer 23

biological barriers against the formation of hybrids

Question 24

post-zygotic isolation

Answer 24

fertilization occurs but lowers fitness
- low hybrid viability and fertility

Question 25

pre-zygotic isolation

Answer 25

stop fertilization from occurring
- mating can’t/doesn’t occur

Question 26

speciation

Answer 26

origin of new species

Question 27

sympatric speciation

Answer 27

speciation without geographic isolation

Question 28

allopatric speciation

Answer 28

formation of new species from geographic isolation