Lec 6- adaption evolution

Question 1

evolution

Answer 1

change in allele frequencies within gene pool over time, can lead to speciation

Question 2

ecology and evolution

Answer 2

intertwined
- no evolutionary processes without ecological interactions
- no ecology w/o population and species produced through evolution

Question 3

Darwin and Galapogos

Answer 3

• organisms must be descended from a common ancestor whose descendants changed after reaching each island in slightly diff ways
• diff species of diff islands more closely related to each other than they are to species found on mainland
• diff species of closely related organisms on diff islands, evolved diff morphologies as consequence of diff environmental pressures = Natural selection

Question 4

People of Evolution (3)

Answer 4

Darwin
Wallace
- both did the diversity of natural selection
Mendel - genetics and traits passed through inheritance
- process that changes populations of organism over time

Question 5

how are characteristics passed from parent to offspring?

Answer 5

• through genes (discrete packets of info)
• alternative forms of genes: alleles

Question 6

alleles

Answer 6

diff forms of a gene

Question 7

gene pool

Answer 7

sum total of all alleles in pop

Question 8

evolution

Answer 8

change in allele frequencies w/in gene pool

Question 9

phenotype

Answer 9

attribute of organism such as behavior, morphology and physiology

Question 10

genotype

Answer 10

set of genes organism carries

Question 11

how does evolution occur?

Answer 11

through changes in allele frequency over time within a population
- requires phenotypic variation that is heritable

Question 12

what causes phenotypic variation?

Answer 12

genes usually expressed due to environmental factors
phenotype combo of organism’s genes under certain environmental conditions

Question 13

phenotypic plasticity

Answer 13

variation as a result of environmental influences
- genes get turned on and off
- hydrangeas changes color based on soil acidity

Question 14

Variation equation

Answer 14

vT = vG + vE
- total = genetic + environmental

Question 15

heritability equation

Answer 15

h2 = vG/vT
= vG/ (vG + vE)
0 = completely environmental determined
1 = completely genetically determined

Question 16

Natural selection

Answer 16

one mechanism of evolution
- many offspring produce, not all survive
- traits vary among individuals w/in pop and may be heritable
- some heritable traits give advantage
- advantageous traits, conferring higher fitness become more common

Question 17

Finches

Answer 17

bill depth varies w/in medium ground finch species
major drought hot n1976-1979
- drought associated w decline in seed abundance and increase in seed hardiness
- some die and population evolved
- bill depth shifted during drought to higher values

Question 18

directional selection

Answer 18

type of natural selection in which extreme phenotype become more frequent
- drought imposed strong selective pressures on beak depth distribution = favoring phenotypes with deeper beaks and crack seeds more easily avoiding starvation

Question 19

stabilizing selection

Answer 19

type of natural selection in which avg phenotype increases in frequency and extreme phenotypes decrease in frequency
- egg size in Ural owls
1. v large and small have low hatching rate
2. low fertility in females producing v small or large eggs

Question 20

disruptive selection

Answer 20

type of natural selection in which 2 or more extreme phenotypes become more frequent and avg phenotype becomes less frequent
- finches w short beaks prefer partners w short beaks and finches w larger beaks tend to prefer mates with larger beaks - non-random mating

Question 21

adaptation

Answer 21

traits that have been selected for through natural selection
- more common and frequent

Question 22

speciation

Answer 22

• physical and ecological processes interact with natural selection and other random processes to produce new species
• gene drift, flow and mutations

Question 23

what is a species

Answer 23

group of actually or potentially interbreeding pop which are reproductively isolated from other groups

Question 24

reproductive isolation

Answer 24

mechanisms of reproductive isolation b/f zygote can be formed
prezygotic: ecological, temporal, behavioral, mechanical

mechanism of repro isolation when zygote forms, but offspring cannot survive or reproduce
postzygotic: hybrid inviability, hybrid sterility

Question 25

allopatric speciation

Answer 25

geographically isolated populations

Question 26

parapatric speciation

Answer 26

continuously distributed population
- too far to mate
- over time = speciation needed

Question 27

sympatric speciation

Answer 27

within range of ancestral population
- coexist
- 2 diff sub-populations with diff behavioral cues