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biosci 94 > midterm 1 > Flashcards

midterm 1 Flashcards

(61 cards)

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1
Q

4 eras of life

A

precambrian
palezoic
mesozoic
cenozoic (present)

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2
Q

8 parts of scale

A
  1. origin of earth (4.6 bil)
  2. earth cools
  3. origin of life (3.6 bil)
  4. oldest prokary fossil
  5. accumulation of O2 in atmospher (2.3 bil)
  6. multicellular organisms
  7. plants colonize land
  8. extinction of dinosaurs
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3
Q

step 1 of life

A

abiotic synthesis of complex organic molecules
miller-urey experiment: placed chemicals present in earth’s early atmosphere under the conditions of early earth to originate life
result- primodial soup (lots of water and diluted chemicals), amino acids, no O2

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4
Q

step 2 of life

A

polymerization: bonding monomers to form polymers

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5
Q

step 3 of life

A

bc all life has cells, macromolecules must be organized in probionts (cell-like structure)

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6
Q

step 4 of life

A

RNA is origin of hereditary material bc bc available (miller urey exp), self replicates, catalytic prop
central dogma:
DNA -> RNA and vice versa, but once reaches proteins it cant be reversed

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7
Q

plato

A

typological thinking: fit into specific categories
issue- didn’t explain how life diversified

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8
Q

lamarck

A

species change through time ✓
each species is a different stage of evolution ⨉
species originate through spontaneous generation ⨉
acquire characteristics, no common ancestry ⨉

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9
Q

charles darwin’s theory of evolution

A

steady change: species change over time
gradualism: change takes place gradually
speciation: new species arise from existing species
common ancestry: all species on earth had a common ancestor
natural selection

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10
Q

natural selection

A

process which individuals with certain heritable traits produce more surviving offspring than individuals without those traits

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11
Q

natural selection based on

A
  1. there’s variation among individuals
  2. variation is heritable
  3. species produce more offspring that what can survive
  4. individuals that are more successful (aka have traits that enable better survival and reproduction) pass these traits to their offspring
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12
Q

fitness

A

measured success in survival

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13
Q

adaptation

A

heritable trait with high fitness

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14
Q

common misconceptions of natural selection

A

doesn’t change individual, acts on individual and changes population
selection isn’t goal directed (purely for survival)
adaptation isn’t perfect

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15
Q

directional selection

A

favors one extreme, causing average to shift

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16
Q

stabilizing selection

A

disfavors both extremes, favors average

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17
Q

disruptive selection

A

favors both extremes, disfavors average

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18
Q

sexual selection

A

individual is more or less fit because of the way they reproduce, caused by fundamental aspect of sex

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19
Q

fundamental aspect of sex

A

females have a greater reproductive cost, so they’re more choosey, making opportunities for males limited

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20
Q

female choice

A

intersexual competition, females more selective so males have to win them over
through visual appearance, nupital gifts

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21
Q

male competition

A

male male competition (aka intrasexual competition)

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22
Q

HWE

A

allele frequencies are not expected to change over time when nothing’s going on
equations: p^2 + 2pq + q^2 = 1
p + q = 1

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23
Q

5 assumptions of HWE

A

no natural selection, random mating, no genetic drift, no gene flow, no mutations

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24
Q

violation of no natural selection

A

results in recessive lethel allele

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25
violation of random mating
self reproduction (selfing) results in exponential decay: bc only heterozygotes produce heterozygote offsprings as generations continue they dec by 50%- aka allele frequency isn't changing but the genotype is inbreeding
26
violation of no genetic drift
genetic drift: allele frequency drift randomly caused by sampling error result in loss or fixation of an allele
27
types of genetic drift
founder effect: change of allele freq from new population established bottleneck effect: population size reduces causing diversity of alleles to dec
28
violation of no gene flow
gene flow: individuals moving between populations causing alleles to be more alike
29
violation of no mutations
mutations: changes in DNA, increases genetic diversity
30
prezygotic isolation
before fertilization temporal, behavioral, mechanical, gametic, habitat
31
biological species concept (BSC)
reproductively isolated individuals represent different species
32
temporal isolation
timing of reproduction differs between species
33
behavioral isolation
potential mate does something unexpected
34
mechanical isolation
genitalia parts don't fit
35
gametic isolation
gametes mate but not compatable on a cellular level
36
habitat isolation
different environments
37
postzygotic isolation
inviability: hybrids don't survive sterility: hybrids are sterile
38
morphospecies concept
look same= same species look diff= diff species
39
phylogenetic species concept
species identified based on evolutionary history
40
types of speciation
allopatric, sympatric
41
allopatric speciation
different location 1. geographic isolation due to dispersal and colonization OR physical splitting 2. genetic isolation 3. divergence
42
genetic isolation
barrier preventing gene flow isolating populations
43
genetic divergence
mutation, selection, genetic drift
44
sympatric speciation
same location 1. no geographic isolation 2. genetic isolation occurs by nonrandom mating 3. divergence
45
fusion
2 populations freely interbreed
46
extinction
if 1 population is a better competitor for shared resources, other is driven to extinction
47
reinforcement of divergence
if hybrid offspring have low fitness, populations kept apart
48
hybrid zone formation
hybridization occurs in distinct geographic area
49
formation of new species
if genes in hybrid offspring allow occupy distinct habitats/use resources, new species forms
50
homology
a feature shared between multiple individuals of different species, due to sharing a common ancestor
51
homoplasy
shared feature not due to sharing a common ancestor due to convergent evolution: natural selection shaped the genetic variation
52
synapomorphies
a shared derived trait
53
prediction 1- evidence for evolution
there should be variation among a species and that variation is heritable
54
prediction 2
there should be evidence of differential survival and reproduction (ex: natural selection)
55
prediction 3
if there has been common ancestry, then molecules and cells should indicate that life has a shared history (ex: central dogma followed in all living things)
56
prediction 4
if there has been common ancestry, the anatomy and structure should indicate that (ex: vestigial traits: structures that have no/reduced function but similar to functioning structures in closely related species- ex: appendix)
57
prediction 5
if life changes over time, there should be evidence of transitional forms in fossils (ex: archaeopteryx- transition between dinosaurs (more lizard like) into birds)
58
prediction 6
there should be evidence of extinction 5 eps of mass extinction: (most well known) end permian extinction- 80-96% of all species disappears esp marine end cretaceous extinction- dinosaurs bye
59
monophyletic
ancestor and all its descendants one snip test: if i cut a node, everything after the node is a descendant from an organism that had that feature, so everything would be cut off
60
polyphyletic
shares traits but not the most recent common ancestor
61
paraphyletic
ancestor and some of its descendants

biosci 94 (4 decks)

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