chapter 17 & 18 test

Question 1

scientific theories

Answer 1

well established explanation of event about the natural world

Question 2

Species vary globally

Answer 2

nimal species inhabited separated but ecologically similar habitats around the globe.

Question 3

Species vary locally

Answer 3

animal species often occupied different habitats within a local area

Question 4

Species vary over time

Answer 4

Explains how some species that have already become extinct resemble those that are living.

Question 5

Jean-Baptiste Lamarck proposed the 2 hypotheses…

Answer 5

1. that organisms could change during their lifetimes by selectively using or not using various parts of their bodies.
2. that the individuals could pass these acquired traits on to their offspring enabling the species to “change” over time

Question 6

why was lamarck wrong

Answer 6

aquired traits are not inherited

Question 7

artificial selection

Answer 7

When nature provides the variations and humans select those they find useful.

Question 8

Natural Selection

Answer 8

is the process by which organisms with variations most suited to their local environment survive and leave more offspring with the same variations.

Question 9

biologocal fitness

Answer 9

how well an organisms adaptations allow it to survive

Question 10

3 conditions needed for natural selection

Answer 10

over productiuon of offspring, inherrtied variation, and struggle to survive

Question 11

principal of common descent

Answer 11

all species – living and extinct – are descended from ancient common ancestors.

Question 12

how old is the earth

Answer 12

4.5 billion years

Question 13

what is a gene pool

Answer 13

all of the genes present in a population

Question 14

relative frequency

Answer 14

– Number of times a particular allele occurs in a gene pool, compared with the number of times other alleles for the same gene occur.

Question 15

do popultions or individuals evolve

Answer 15

popukations

Question 16

what are the 2 sources of genetic variation

Answer 16

mutation- any change in dna sequence

genetic recombination- due to sex (crossing over)

Question 17

what are the 4 mechanisms for revolutionary change

Answer 17

genetic drift
gene flow
non random mating
natural selection

Question 18

what is genetic drift

Answer 18

netic drift occurs in SMALL populations when an allele becomes more or less common simply BY CHANCE. Genetic drift is a random change in allele frequency.
• 2 types
– bottleneck effect
– founder effect

Question 19

bottle neck effect

Answer 19

is a change in allele
frequency following a dramatic reduction in the
size of a population.
• Ex. A disaster may kill many individuals in a population and the surviving population’s gene pool may contain different gene frequencies from the original pool.

Question 20

the founders effect

Answer 20

The founder effect occurs when allele frequencies change as a result of the migration of a small subgroup of a population.
• Two groups from a large, diverse population could produce new populations that differ from the original group.

Question 21

what happpens to the allele frequency in genetic drift

Answer 21

it changes because dome individuals go off to start their own pop.

Question 22

gene flow

Answer 22

The movement into or out of a population can change the variations in the gene pool.

Question 23

non random mating

Answer 23

If mate choice is not based on chance or opportunity, but instead mates are chosen due to some characteristic that is more desirable… allele frequencies in a population will change.

Question 24

how does natural selection effect single genes

Answer 24

Natural selection on single-gene traits can lead to changes in allele frequencies and thus to changes in phenotype frequencies

Question 25

Natural selection on polygenic traits

Answer 25

1. directional selection • 2. stabilizing selection • 3. disruptive selection

Question 26

directional selerction

Answer 26

one extreme variation is selected for (highest fitness) BELL CURVE SHIFTS LEFT OR RIGHT

Question 27

stabilizing selection

Answer 27

average form is selcted for

NARROW CURVE

Question 28

disruprive selection

Answer 28

both extremes are selcted for, average is selected against 2 CURVES GO UP MIDDLE GOES DOWN (2 grouos)

Question 29

when dors speciation occur

Answer 29

when pops. become reproductively isolated

Question 30

behavioral isolation

Answer 30

2 org. have different mating behaviors, wont breed

Question 31

geographic isolation

Answer 31

sepersted by barrier

Question 32

temporal isolation

Answer 32

(timing)

breed at dif times

Question 33

Hardy-Weinberg Principle

Answer 33

– 1. the population must be very large
– 2. there can be no mutations
– 3. there must be random mating
– 4. there can be no movement into or out of the population
– 5. no natural selection