test 2: evidence for evolution

Question 1

convergent evolution

Answer 1

different ancestor, same solution to a problem (not true homology)
- ancestors are not related, similar morphology or lifestyle (often same habitat)

Question 2

how does convergent evolution occur?

Answer 2

• similar environmental pressure = similar adaptation
• ex: birds and bats
• ex: marsupials vs placentals

Question 3

divergent evolution

Answer 3

same ancestor, different morphologies based on habitat (true homology)
- common ancestor, different morphology or lifestyle (different habitats)

Question 4

how does divergent evolution occur?

Answer 4

• changing environment of different area
• also called adaptative radiation
• ex: pentadactyl limbs (snakes, birds, lizards)

Question 5

microevolution

Answer 5

how adaptations evolve in a particular gene pool/population (ex: particular bird on a particular island)

Question 6

macroevolution

Answer 6

how adaptations evolve above the species level (ex: feathers in birds from dinosaurs)

Question 7

methods for examining evolution

Answer 7

1- fossil record
2- comparitive anatomy
3- molecular biology

Question 8

fossil record

Answer 8

• 99% of species are extinct
• hard parts fossilized (ex: bone)
• parts of organisms are protected from bacterial decay
• certain periods have more fossils than others
• carbon dating

Question 9

radiometric dating (fossils)

Answer 9

rate of decay expressed by half-life of parent isotopes

Question 10

half-life

Answer 10

time required for 50% of parent isotope to decay

• unique for each isotope
• not affected by environmental factor

Question 11

half-life of Carbon14

Answer 11

5730 years (+- 4000 years)

Question 12

oldest known fossils

Answer 12

3. 5 billion year old stromatolites:

- rocklike structures composed of layers of bacteria and sediment

Question 13

biogeography

Answer 13

studying the distribution of organisms (species on one island hopping to another and evolving)

Question 14

continental drift

Answer 14

• ancestral groups found only in africa
• new world vertebrates didn’t migrate (spread to SA, when two continents were connected)
• movement of continents caused mountain building, drainage changes, changes in the shallows = big effect on evolution
• organism distribution, fossil magnetism, coastline shape, present movements

Question 15

islands

Answer 15

• often inhabited by endemic species
• nearest relatives on mainland
• idea of a bird getting blown off course, landing on an island and adapting (galapagos finches)

Question 16

radiative adaptation

Answer 16

australia never had the same type of competition between placentals and marsupials, so marsupials under went radiative adaption (ex: 5 species to 25 species)

Question 17

niche

Answer 17

ecological role of an organism, how it fits into it’s habitat and resource partitioning
- for biogeography and radiative adaption: selective pressure of environment dictates a particular solution

Question 18

how do two species survive in same area?

Answer 18

different niche, avoid conflict (don’t overlap niches)

Question 19

comparative anatomy

Answer 19

• compare one structure in a number of organisms
• many limbs have minimal modifications
• had they evolved separately, they would have been better suited
  therefore, must have common ancestor
  ex: pentadactyl limb

Question 20

pentadactyl limb

Answer 20

humerus, radius, ulna, carpals, metacarpals, phalanges

Question 21

ex of comparative anatomy

Answer 21

• pentadactyl limb
• all extant vertebrates have 4 limbs
• all vertebrates have pharyngeal pouches at some point
  therefore, must have evolved from ancestor with gill pouches and 4 limbs

Question 22

comparative embryology

Answer 22

“ontogeny recapitulates phylogeny”

• development of embryo follows steps during evolution of a species (evolutionary development follows evolution of your species)
• process itself is evolving and provides clues to phylogeny

Question 23

vestigial structure

Answer 23

remnants of structures in ancestors not important now (ex: tailbone)

Question 24

molecular biology

Answer 24

• DNA/proteins of different species comparared
• closely related varies less than distantly related
• lots of variation, short amount of time
• rate of evolution for these proteins found can estimate time since common ancestor
• difference between 2 species depends on length of time since their common ancestor

Question 25

molecular biology ex

Answer 25

cytochrome (all eukaryotes), histone IV (dna, chromatin), hemoglobin, fribrinopeptides

Question 26

dna-dna comparisons

Answer 26

- base sequences of different species compared - most similarities = more closely related - used with other methods to confirm findings

Question 27

example: pepper moth

Answer 27

- british peppered moth - polymorphic light/dark forms - clean vs dirty city areas - light morphs in clean areas, dark in dirty - camouflage from birds

Question 28

antibiotic resistance

Answer 28

bacteria mutate to resist, forms a resistant pop | - also HIV, tuberculosis

Question 29

pesticide resistance

Answer 29

DDT - stable flies | - artificial selection (think livestock, salmon, dogs, cats)

Question 30

causes of microevolution

Answer 30

``` 1- mutations 2- genetic drift 3- founder effect 4- bottleneck effect 5- geneflow 6- assortative mating 7- natural selection ```

Question 31

mutations

Answer 31

new alleles

Question 32

genetic drift

Answer 32

random change in allele frequency due to chance alone (usually small pop for this to occur)

Question 33

founder effect

Answer 33

few individuals colonize new area and their alleles are what form new pop (islands)

Question 34

bottleneck effect

Answer 34

few individuals survive natural disaster (earthquake, flood, drought)

Question 35

founder and bottleneck effect on population

Answer 35

reduces pop and alleles to choose from

Question 36

genetic drift effects on pop

Answer 36

changes alleles in population

Question 37

geneflow

Answer 37

change in allele frequencies due to migration

Question 38

assortative mating

Answer 38

near by populations tend to mate together more often, only go so far to find a mate - organisms tend to choose mates with similar phenotypes (match each other in size)

Question 39

natural selection

Answer 39

only cause of microevolution that is adaptive - individuals with more fitness leave more offspring - only cause that is a judgement on your traits