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DAT BIOLOGY > Chapter 8: Evolution > Flashcards

Chapter 8: Evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

evolution

A

changes in populations, species or groups; changes in allele frequencies in populations over time

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2
Q

microevolution

A

changes in allele frequencies that occur over time within a population (due to mutation, selection, gene flow, and drift)

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3
Q

macroevolution

A

patterns of changes in groups of related species over broad periods of geologic time.
— patterns determine phylogeny=evolutionary relationships among species and groups of species

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4
Q

Lamarck theory

A
  1. use and disuse: body parts can develop with increased usage, unused parts are weakened (correct in athletes)
  2. inheritance of acquired characteristics: body features acquired during lifetime can be passed down to offspring (incorrect, since only changes in genetic material in cells can be passed to offspring)
  3. natural transformation of species: organisms produced offspring with changes, transforming each later generation slightly more complex (no extinction or splits into more species)=> incorrect!
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5
Q

natural selection

A
  1. darwinism

2. survival of the fittest=> now called neo-Darwinism (synthetic theory of evolution)

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6
Q

evidence for evolution

a.paleontology

A
  1. fossils reveal prehistoric existence of extinct species
  2. often found in sediment layers (deepest fossils represent oldest specimens)
  3. large rapid changes produce new species
    types: actual remains, petrification, imprints, molds, casts
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7
Q

b. biogeography

A
  1. geography to describe distribution of species
  2. unrelated species in different regions of world look alike when found in similar environemnt
    - —continental drift=supercontinent Pangea slowly broke apart to 7 continents
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8
Q

c. embryology

A
  1. similar stages of development (ontogeny) among related species => establish evo. relationships (phylogeny)
  2. gill slits and tails are found in fish, chicken, pig, and human embryos
  3. “Ontogeny recapitulates phylogeny”- this specific recapitulation theory is considered defunt, basically said that embryological stages represent our past evo. ancestors
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9
Q

comparative anatomy

A

describes two kind of structure that contribute to identification of evo relationships

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10
Q

a. homologous structure

A
  1. body parts that resemble one another in different species from common ancestor
  2. similar structure… different function due to living in different environment***be careful using this
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11
Q

analogous structure

A
  1. body parts that resemble one another in different species because they evolved independently as adaptation to their environments
  2. different structure… same function (in comparison with other species***be careful using this
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12
Q

natural selection

A

responsible for producing adaptations (superior inherited traits) that increase individual’s fitness (ability to survive, leave offspring

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13
Q
  1. populations possess an enormous reproductive potential
A

if all offspring produced and survived

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14
Q
  1. population size remain stable
A

populations generally fluctuate around a constant size

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15
Q
  1. resources are limited
A

resources do not increase as population grow larger

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16
Q
  1. individuals compete for survival
A

growing pop will exceed available resources=competition

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17
Q
  1. there is variation among individuals in a population
A

such as skin color (very pale to dark)… such as continuous variation

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18
Q
  1. much variation is heritable
A

DNA is passed down

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19
Q
  1. only the most fit individuals survive
A

survival of the fittest

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20
Q
  1. evolution occurs as favorable traits accumulate in the population
A

best adapted individuals=> best adapted offspring leave most offspring

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21
Q

stabilizing selection

A
  1. bell curve looking
  2. ex: average height of human in middle
  3. favors intermediate
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22
Q

directional selection

A
  1. favors traits that are at one extreme of a range of traits
  2. traits at opposite extreme are selected against
  3. after many generations => changes in allele frequencies (such as insecticide resistance)
    ex: Industrial melanism= selection of dark colored (melanic) varities in various species of moths (peppered moths) as result of industrial pollution
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23
Q

disruptive selection

A
  1. occurs when environment favors extreme or unusual trains while selecting against common traits
  2. short and tall are favored while average is selected against
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24
Q

sexual selection

A
  1. differential mating of males (or females) in a poplation.
  2. female chooses superior males=> increase fitness of offspring; they invest greater energy so they maximize quality
  3. males increase fitness of offspring by maximizing quantity
  4. male competition: leads to fights; mating opportunities awarded to strongest male, favors traits like musculature. horns, large stature, etc.
  5. Female choice, leads to traits/behaviors in males that are favorable to female, favors traits like colorful plumage or elaborate mating behavior
  6. result often leads to sexual dimorphism= differences in appearances of males and females=> becomes a form of disruptive selection
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25
Q

artificial selection

A

a form of directional selection carried out by humans when they breed favorable traits (not natural selection)

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26
Q

sources of variation

a. mutation

A

introduce a new allele

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27
Q

b. sexual reproduction

A

genetic recombination via

  1. crossing over
  2. independent assortment
  3. random joining of gametes
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28
Q

c. diploidy

A
  1. presence of two copies of each chromosome

2. in heterozygous conditions, recessive allele is stored for later generations=>more variations maintained in gene pool

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29
Q

d. outbreeding

A

mating with unrelated partners=>mixing different alleles=> new allele combinations

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30
Q

e. balanced polymorphism

A
  1. maintenance of different phenotypes in pops. (one is usually best and increased in allele frequency)
  2. However, polymorphisms (coexistence or two/more different phenotypes) can exist and be maintained
  3. 3 ways: heterozygote advantage, hybrid vigor, frequency-dependent selection
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31
Q

heterozygote advantage

A

heterozygous condition bears greater advantage than either homozygous conditions
ex: sickle cell (AA,AS,SS). AS is 14% in Africa because it has resistance against malaria when it should be close to 0%

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32
Q

hybrid vigor (heterosis)

A

superior quality of offspring resulting from crosses between two different inbred strains of plants=> hybrid superior quality results from reduction of loci with deletion of recessive homozygous conditions and increase in heterozygous advantage.

33
Q

frequency-dependent selection (minority advantage)

A
  1. least common phenotypes have selective advantage.
  2. common phenos are selected against
  3. rate will increase in frequency and will be selected against and repeat
  4. predators (search image of common phenos in prey)=> rare escapes; rare eventually becomes common, cycle repeats
34
Q

neutral variation

A

variation without selective value (fingerprints in humans)

35
Q

geographic variation

A
  1. variation of species dependent on climate or geographic conditions
  2. a graded variation of a pheno due to this is known as cline
  3. variation from north/south environments is a north-south cline
36
Q

causes of changes in allele frequencies

a. natural selection

A

increase or decrease of allele frequencies due to environment

37
Q

b. gene flow

A

introduction/removal of alleles from population when individuals leave (emigration) or enter population (immigration)

38
Q

c. genetic drift

A

random increase or 1.decrease of allele by change

  1. small population => larger effect
  2. two types: founder and bottleneck
39
Q

founder effect

A

allele frequencies in group of migrating individuals are (by chance) not the same as that of their population origin

40
Q

bottleneck

A

occurs when population undergoes a dramatic decrease in size (natural catastrophe, etc)=> vulnerable to genetic drift

41
Q

d. nonrandom mating

A

individuals choose mates based upon their particular traits

  1. inbreeding: individuals mate with relatives … selfing (most extreme)
  2. sexual selection: females choose males based on superior traits
42
Q

e. mutations

A

introduce new alleles that may provide a selective advantage —- usually they are deleterious

43
Q

Hardy-Weinberg Equilibrium (genetic equilibrium)

A

=allele frequencies remain constant from generation to generation=>no evolution

  1. no mutations
  2. all traits are neutral (no natural selection)
  3. population must be isolated (no gene flow)
  4. large populations (no genetic drift)
  5. mating is random
  6. no net migration
44
Q

HWE equations

A
  • allele freqs for each allele (p,q)
  • frequency of homos (p2, q2)
  • freq of hetero (pq + qp = 2pq)
  • all alleles sum to 100% (p +q=1)
  • all individuals sum to 100% (p2+2pq+q2=1)
  • ** BOTH ALLELE AND INDIVIDUALS MUST BE = 1
45
Q

HWE example

A

A plant population with 84% red flowers (R) and 16% white flowers (r).
q2=.16 (rr) …. q= .4
p2+2pq=.84 (RR +Rr)
*** we can find q and p by taking square-root and plug in the two equations to find hetero freq and homo dominant freq.

46
Q

speciation

A

formation of new species

47
Q

species

A

a group of individuals capable of interbreeding

48
Q

allopatric speciation

A
  1. population is divided by geographic barrier
  2. interbreeding between two populations is prevented
  3. gene frequencies in two population can diverge due to natural selection, mutation, genetic drift
  4. if gene pool is sufficiently diverge .. will not interbreed when barrier is removed… new species is formed
  5. this form of speciation can be through dispersal =group is isolated by being physically removed form the original location of the larger group)
  6. vicariance=group is isolated by geographic barrier but in the same overall location of the larger group
49
Q

sympatric speciation

A
  1. formation of new species without presence of geographic barrier
  2. 3 ways listed below…
50
Q

a. balanced polymorphism

A
  1. natural selection due to polymorphism
  2. example: different color in insects, one color can camouflage to different substrate, and the other that can’t will be eaten … only insects with same color can mate (isolated from other subpopulations)
51
Q

b. polyploidy

A
  1. possession of more than normal two sets of chromosomes (nondisjuction causes 3n or 4n in plants)
  2. two viable diploid gametes and two sterile gametes with no chromosomes…. tetraploid is formed… repeat with diploid gametes male/female .. reproductive isolation with normal gametes
52
Q

c. hybridization

A
  1. two different forms of a species (closely related species) mate and produce along a geographic boundary called hybrid zone
  2. more genetic variations… hybrid can live beyond range of either parent due to adaptations to environment.. under different selection pressures so diverge from both parent populations
53
Q

adaptive radiation

A
  1. rapid evolution of many species from a single ancestor; occurs when ancestral species is introduced to an area where diverse geographic/ecological conditions are available for colonization
54
Q

maintaining reproductive isolation

A

prevent gene flow= no separation by geo barrier; may be randon or result of NS)

55
Q

prezygotic isolating mechanism

A
  1. prevent fertilization
    a. habitat isolation=species do not encounter
    b. temporal isolation= species mate/flower during different seasons/time
    c. mechanical isolation: male/female genitalia are not compatible
    d. gametic isolation=male gametes do not survive in environment of female gametes (gametes do no recognize others)
56
Q

postzygotic isolating mechanisms

A
  1. mechanisms that prevent formation of fertile progeny
    a. hybrid inviability= zygote fails to develop properly and dies before reaching reproductive maturity
    b. hybrid sterility=hybrids become functional adults but cannot reproduce
    c. hybrid breakdown= hybrids produce offspring that have reduced viability/fertility (hybrid’s children can’t reproduce!)
57
Q

divergent evolution

A

two or more species that originate from common ancestor and become increasingly different over time (result of speciation)

58
Q

convergent evolution

A

two unrelated species that share similar traits by environment (analagous traits)

59
Q

parallel evolution

A

two related species made similar evolutionary changes after their divergence from common ancestor

60
Q

coevolution

A

evolution of one species in response to new adaptations that appear in another species (predator/prey) … pollinator and flower… clam and its predator (biol 412)

61
Q

macroevolution

A

patterns of evolution for groups of species over extended periods of geologic time

62
Q

phyletic gradualism

A

evolution occurs by gradual accumulation of small changes; but unlikely to be valid because intermediate stages of evolution are missing (no fossils); fossils only reveals major changes in groups of organisms

63
Q

punctuated equilibrium

A

evolutionary history consists if geologically long periods of stasis with little/ no evolution followed by geologically short periods of rapid evolutions. Absence of fossils reveals intermediate stages of evolution is considered data that confirms rapid evolutionary events

64
Q

origin of life

A

a. universe is 12-15 billion years old
b. solar system 4.6 bill yrs
c. earth 4.5 bill yrs
d. microfossils of prokaryotes 3.6 bill
e. photosynthetic bacteria 2.3 bill yrs
f. eukaryotes 1.5 billion years ago

65
Q
  1. earth and atmosphere form
A

a. through volcanoes

b. CH4, NH3, CO, CO2, H2, N2, H2O, S, HCl, HCN, little/no O2

66
Q
  1. primordial seas formation
A

as earth cooled=>gases condense=> sea with water and minerals

67
Q
  1. complex molecules were synthesized
A

formation of organic soup from inorganic, energy from UV, lighting, heat, radiation=>acetic acid, formaldehyde, and amino acids

  • –Oparin and Haldane: organic soup; if there was O2 (very reactive), no organic molecules would have formed … Oparins hypothesis was that origin Earth environment was reducing (providing chemical requirements to produce complex molecules from simple building blocks. In an oxidizing environment you’d break complex molecules apart.)
  • –Stanley Miller: tested theory above and produced organic molecules … Miller and Urey used ammonia, methane, water, and hydrogen sealed + stimulated lightning => saw several organic molecules, AA’s starting materials, but no Nucleic Acids
68
Q

4.polymers and self-replication

A

monomers=>polymer (dehydration condensation)

—proteinoids are abiotically produced polypeptides <=amino acids dehydration on hot, dry substrates confirms this

69
Q
  1. organic molecules were concentrated/isolated into protobionts
A

a. protobionts=precursors of cells = like cells, metabolically active but unable to reproduce
b. microspheres/liposomes/coacervates=spontaneously formed lipid or protein bilayer bubbles … are experimentally (abiotically) produced protobionts that have some selective permeable qualties

70
Q
  1. primitive heterotrophic prokaryotes
A

obtained materials by consuming other organic substances (pathogenic bateria)

71
Q
  1. primitive autotrophic prokaryotes
A

mutation, heterotroph gained ability to produce its own food=> cyanobacteria

72
Q

8.oxygen and ozone layer + abiotic chemical evolution ended

A

by production of photosynthetic activity of autotrophs
—UV light + oxygen = ozone layer=blocks energy for abiotic synthesis of organic materials=termination of primitive cells

73
Q

endosymbiotic theory

A
  1. eukaryotes formed
  2. eukaryotic cells originated mutually among prokaryotes (mitochondria, chloroplast establish resident inside another prokaryote).
    EVIDENCE
  3. thylakoid membrane of chloroplast resemble photosynthetic membranes of cyanobacteria
  4. mito and chloro have own circular DNA not wrapped around histones
  5. ribosomes of these organelles resemble those of bacteria
  6. they reproduce independently via process similar to binary fission
  7. two membranes
74
Q
  1. organic molecules were concentrated/isolated into protobionts
A

a. protobionts=precursors of cells = like cells, metabolically active but unable to reproduce
b. microspheres/liposomes/coacervates=spontaneously formed lipid or protein bilayer bubbles … are experimentally (abiotically) produced protobionts that have some selective permeable qualties

75
Q
  1. primitive heterotrophic prokaryotes
A

obtained materials by consuming other organic substances (pathogenic bateria)

76
Q
  1. primitive autotrophic prokaryotes
A

mutation, heterotroph gained ability to produce its own food=> cyanobacteria

77
Q

8.oxygen and ozone layer + abiotic chemical evolution ended

A

by production of photosynthetic activity of autotrophs
—UV light + oxygen = ozone layer=blocks energy for abiotic synthesis of organic materials=termination of primitive cells

78
Q

endosymbiotic theory

A
  1. eukaryotes formed
  2. eukaryotic cells originated mutually among prokaryotes (mitochondria, chloroplast establish resident inside another prokaryote).
    EVIDENCE
  3. thylakoid membrane of chloroplast resemble photosynthetic membranes of cyanobacteria
  4. mito and chloro have own circular DNA not wrapped around histones
  5. ribosomes of these organelles resemble those of bacteria
  6. they reproduce independently via process similar to binary fission
  7. two membranes

DAT BIOLOGY (14 decks)

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