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Biology-Evolution Flashcards

1
Q

evolution

A

changes that occur in a population, species, or group of species; changes in allele frequencies in populations over time

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2
Q

microevolution

A

describes how populations of organisms change from generation to generation and how new species originate; 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

describes changes in groups of related species over broad periods of geologic time; patterns of changes that determine phylogeny

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4
Q

phylogeny

A

evolutionary relationships among species and group of species

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5
Q

Larmarck’s 3 important ideas

A
  1. Use and disuse:
    body parts of organisms develop w/ increased usage, while unused parts weaken
  2. Inheritance of acquired characteristics-
    body features acquired during the lifetime of an organism ( such as muscle bulk) could be passed on to offspring. This was wrong.
  3. Natural transformation of species-
    organisms produced offspring w/ changes, transforming each later generation into a slightly more complex form (no extinction or splits into more species)
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6
Q

natural selection

A

“survival of the fittest” was the driving force of evolution that is now called Darwinism.

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7
Q

neo-Darwinism, the synthetic theory of evolution, or the modern synthesis

A

genetics was incorporated into evolutionary thinking, creating a new, more comprehensive view of evolution

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8
Q

evidence for evolution

A
  1. Paleontology
  2. Biogeography
  3. Embryology
  4. Comparative anatomy
  5. Molecular biology
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9
Q

(evidence for evolution) Paleontology

A

fossils reveal the prehistoric existence of extinct species.

often found in sediment layers, (deepest => oldest specimens). (Large, rapid changes produced new species)

fossil types: actual remains, petrification, imprints, molds, and casts

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10
Q

(evidence for evolution) Biogeography

A

geography to describe distribution of species; unrelated species in different regions of world look alike when found in similar environment.
ex. rabbits and austrailian hare wallaby

continental drift- supercontinent Pangea slowly broke apart to 7 continents

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11
Q

(evidence for evolution) Embryology

A

similar stages in development (ontogeny) among related species. The similarities help establish evolutionary relationships (phylogeny)

Gill slits and tails are found in fish, chicken, pig, and human embryos

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12
Q

(evidence for evolution) Comparative anatomy

A

describes two kinds of structures that contribute to the identification of evolutionary relationships among species: homologous structures and analogous structures

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13
Q

(evidence for evolution) Comparative anatomy: Homologous structures

A

body parts that resemble one another indifferent species because they have evolved from a common ancestor

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14
Q

(evidence for evolution) Comparative anatomy: Analogous structures

A

body parts that resemble one another in different species, not because they have evolved from a common ancestor, but because they evolved independently as adaptations to their environments.

The fins and body shapes of sharks, penguins, and porpoises are analogous because they are adaptations to swimming

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15
Q

(evidence for evolution) Molecular biology

A

examines the nucleotide and amino-acid sequences of DNA and proteins from different species. Closely related species share higher percentages of sequences. In addition, all living things share the same genetic code.

More than 98% of the nucleotide sequences in humans and chimpanzees are identical. AA’s in cytochrome c often compared

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16
Q

natural selection

A

the differences in survival and reproduction among individuals in a population as a result of their interaction w/ their environment; responsible for producing adaptations (superior inherited traits) that increase individual’s fitness (ability to survive, leave offspring)

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17
Q

fitness

A

the relative ability to survive and leave offspring

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18
Q

Darwin’s arguments for theory of evolution by natural selection

A
  1. Populations possess an enormous reproductive potential: if all offspring produced and survived
  2. Population sizes remain stable: pop. generally fluctuate around a constant size
  3. Resources are limited: resources do not increase as pop. grow larger
  4. Individuals compete for survival: growing pop will exceed available resources => compete
  5. There is variation among individuals in a population: such as skin color
  6. Much variation is heritable: DNA is passed down
  7. Only the most fit individuals survive: survival of the fittest
  8. Evolution occurs as favorable traits accumulate in the population: best adapted individuals => best adapted offspring leave most offspring.
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19
Q

What are the five types of selection?

A
  1. Stabilizing selection
  2. Directional selection
  3. Disruptive selection
  4. Sexual selection
  5. Artificial selection
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20
Q

stabilizing selection

A

eliminates individuals that have extreme or unusual traits; individuals w/ the most common trait are the best adapted

bell curve (avg. height in human is in middle); favors an intermediate

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21
Q

directional selection

A

favors traits that are at one extreme of a range of traits, traits at the opposite extreme are selected against.

After many generations => changes in allele frequencies (such as insecticide resistance)

ex.: insecticide resistance, peppered moth

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22
Q

industrial melanism

A

the selection of dark-colored (melanic) varieties in various species of moths as a result of industrial pollution

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23
Q

disruptive selection

A

occurs when the environment favors extreme or unusual traits

example: height variation in weeds of lawns and in the wild

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24
Q

sexual selection (nonrandom mating)

A

the differential mating of males (sometimes females) in a population

example: females increase fitness by increasing the quality of their offspring by choosing superior males

males increase fitness by maximizing the quantity of offspring produced

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25
Q

What are two kinds of sexual selection?

A

male competition and female choice

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26
Q

male competition

A

a kind of sexual selection that leads to contests of strength that award mating opportunities to the strongest males.

ex.: evolution of antlers, horns, and large stature or musculature are examples of this kind of sexual selection

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27
Q

female choice

A

leads to traits or behaviors in males that are attractive to females

ex: colorful bird plumage or elaborate mating behaviors

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28
Q

sexual dimorphism

A

differences in the appearance of males and females => becomes form of disruptive selection

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29
Q

artificial selection

A

form of directional selection carried out by humans when breed animals that possess desirable traits. This is not “natural”

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30
Q

mutations

A

provide the raw material for new variation. They can invent alleles that never before existed in the gene pool. Most mutations are deleterious, or harmful

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31
Q

sexual reproduction

A

creates individuals w/ new combinations of alleles. These rearrangements, or genetic recombination (crossing over, independent assortment of homologues, and random joining of gametes)

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32
Q

crossing over

A

exchanges of DNA between nonsister chromatids of homolgous, occurs during prophase I of meiosis

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33
Q

independent assortment of homologues

A

during metaphase I creates daughter cells w/ random combinations of maternal and paternal chromosomes

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34
Q

random joining of gametes

A

during fertilization contributes to the diversity of gene combinations in the zygote

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35
Q

What are sources of variation?

A
  1. mutations
  2. sexual reproduction
  3. diploidy
  4. outbreeding
  5. balanced polymorphism
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36
Q

diploidy

A

the presence of 2 copies of each chromosome in a cell

in the heterozygous condition (when two different alleles for a single gene locus are present), the recessive allele is hidden and “stored” for future generations

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37
Q

outbreeding

A

mating w/ unrelated partners, increases the possibility of mixing different alleles and creating new allele combinations

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38
Q

balanced polymorphism

A

the maintenance of different phenotypes in a population through heterozygote advantage, hybird vigor (heterosis), or frequency-dependent selection (or minority advantage)

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39
Q

heterozygote advantage

A

occurs when the heterozygous condition bears a greater selective advantage than either homozygous condition

Sickle cell (AA, AS, SS), AS is 14% in Africa because it has resistance against malaria

40
Q

hybrid vigor (heterosis)

A

superior quality of offspring resulting from crosses between 2 different inbred strains of plants.

The superior hybrid quality results from a loci reduction w/ deleterious homozygous recessive conditions and an increase in loci w/ heterozygote advantage.

      Ex.: a hybrid of corn, developed by crossing 2 different corn strains that were highly inbred, is more resistant to disease and produces larger corn ears than either of the inbred strains
41
Q

frequency-dependent selection (or minority advantage)

A

least common phenotypes have a selective advantage. Common phenotypes are selected against. Phenotypes alternate between low and high frequencies , thus maintaining multiple phenotypes.

search image of common phenotypes => rare escape; rare eventually becomes common, cycle repeats

42
Q

What are fives causes of changes in allele frequencies?

A
  1. natural selection
  2. mutations
  3. gene flow
  4. genetic drift
  5. nonrandom mating
43
Q

natural selection

A

increase/decrease in allele frequencies due to the impact of the environment

44
Q

gene flow

A

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

45
Q

genetic drift

A

random increase/decrease of alleles. There are two kinds: founder effect and bottleneck

46
Q

founder effect (genetic drift)

A

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

47
Q

bottleneck (genetic drift)

A

population undergoes a dramatic decrease in size. (natural catastrophe, predation, and disease)

48
Q

nonrandom mating

A

individuals choose mates based upon their particular traits.

There are two kinds that are commonly seen: inbreeding and sexual selection

49
Q

inbreeding (nonrandom mating)

A

occurs when individuals mate w/ relatives

50
Q

Hardy-Weinberg equilibrium (genetic equilibrium)

A

allele frequencies in a population remain constant from generation to generation => no evolution.

  1. All traits are selectively neutral (no natural selection)
  2. Mutations do not occur.
  3. The population must be isolated from other populations (no gene flow)
  4. The population is large (no genetic drift)
  5. Mating is random
51
Q

how is genetic equilibrium determined?

A
  1. Allele frequencies for each allele (p, q)
  2. Frequency of homozygotes (p^2, q^2)
  3. Frequency of heterozygotes (pq + qp = 2pq)

Also, the following equations hold:

  1. p + q = 1 (all alleles sum to 100%)
  2. p^2 + 2pq + q^2= 1 (all individuals sum to 100%)

for example see pg. 135

52
Q

species

A

group of individuals capable of interbreeding.

53
Q

speciation

A

the formation of new species, occurs by the following processes: allopatric speciation, sympatric speciation, or adaptive radiation

54
Q

allopatric speciation

A

pop. is divided by a geographic barrier so that interbreeding between the 2 resulting pop. is prevented. If the gene pools sufficiently diverge, then interbreeding between the populations will not occur if the barrier is removed
e. g. (mountain ranges, rivers, any region that excludes vital resources

55
Q

sympatric speciation

A

formation of new species w/o the presence of a geographic barrier. This may happen through balanced polymorphism, polyploidy, or hybridization

56
Q

balanced polymorphism

A

natural selection due to polymorphism.

ex: an insect pop. has a polymorphism for color. Each color provides camouflage to a different substrate, and if not camouflaged the insect is eaten. Under these rules, only insects w/ the same color can mate. Thus, similarly colored insects are reproductively isolated from other subpopulations, and their gene pools diverge as in allopatric speciation

57
Q

polyploidy

A

the possession of more than the normal two sets of chromosomes found in diploid (2n) cells.

(3n,4n in plant two viable diploid gametes and two sterile games with no chromosomes => tetraploid 4n zygote formed => repeat with diploid gametes male/female => reproductive isolation with normal gametes)

58
Q

hybridization

A

2 different forms of a species (closely related species) mate and produce progeny along a geographic boundary called hybrid zone (more genetic variations => hybrid can live beyond range of either parents)

59
Q

adaptive radiation

A

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

60
Q

What are the two categories of isolating mechanisms?

A

prezygotic isolating mechanisms- prevent fertilization

postzygotic isolating mechanisms-prevent the formation of fertile progeny

61
Q

Reproductive isolation: prezygotic isolating mechanisms

A
  1. habitat isolation- species do not encounter one another
  2. temporal isolation- species mate or flower during different seasons or times of day
  3. behavioral isolation-species does not recognize another species as a mating partner because it does not perform the correct mating ritual
  4. mechanical isolation- male/female genitalia are structurally incompatible or when flower structures select for different pollinators.
  5. gametic isolation- male gametes do not survive in the environment of the female gamete do not recognize others
62
Q

Reproductive isolation: postzygotic isolating mechanisms

A
  1. hybrid inviability- zygote fails to develop properly and dies b4 reaching reproductive maturity
  2. hybrid sterility- hybrids become functional adults, but are reproductively sterile (eggs or sperm are nonexistent or dysfunctional)
  3. hybrid breakdown- hybrids produce offspring that have reduced viability or fertility
63
Q

what are the four patterns of evolution?

A
  1. divergent evolution- describes 2 or more species that come from a common ancestor and have become different over time
  2. convergent evolution- describes 2 unrelated species that share similar traits because each adapted to similar ecological lifestyles/conditions
  3. parallel evolution-describes 2 related species that have made similar evolutionary changes after their divergence from a common ancestor
  4. coevolution-evolution of 1 species in response to new adaptations that appear in another; occurs bet. predator/prey, pollinators/flowering plants, pathogens/animal immune systems
64
Q

macroevolution

A

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

65
Q

What are the 2 macroevolution theories?

A
  1. phyletic gradualism-argues that evolution occurs by the gradual accumulation of small changes. Individual speciation events/major changes in lineages occur over long periods of geologic time.
  2. punctuated equilibrium- evolutionary history consists of geologically long periods of stasis w/ little/no evolution, interrupted, or “punctuated” by geologically short periods of rapid evolution. The absence of fossils revealing intermediate stages of evolution is considered data that confirms rapid evolutionary events
66
Q

chemical evolution

A

describes the processes that are believed to have contributed to the formation of the first living things.

67
Q

heterotroph theory

A

proposes that the first cells were heterotrophs (incapable of making their own food)

68
Q

origin of life

A
  1. the earth and its atmosphere formed (CO, CO2, H2, N2, H2O, S, HCl, HCN, but little to no O2)
  2. the primordial seas formed (gases condensed into water and minerals as earth cooled)
  3. complex molecules were synthesized (formation of org. soup from inorganic, energy from UV, lightin, heat, radiation => acetic acid, formaldehyde and amino acids
  4. Polymers and self-replicating molecules were synthesized
  5. Organic molecules were concentrated and isolated into protobionts
  6. primitive heterotrophic prokaryotes formed
  7. primitive autotrophic prokaryotes were formed
  8. oxygen and the ozone layer formed and abiotic chemical evolution ended
  9. eukaryotes formed
69
Q

origin of life: where did the energy come from that catalyzed the formation of organic molecules from inorganic molecules?

A

came from mostly UV light, but also lightening, radioactivity, and heat

70
Q

origin of life: who were A.I. Oparin and J.B.S. Haldane?

A

they independently theorized that simple molecules were able to form only because oxygen was absent

71
Q

origin of life: who was Stanley Miller?

A

he tested the theories os Oparin and Haldane by simulating an experiment under primordial conditions

72
Q

origin of life: protenoids

A

abiotically produced polypeptides. They can be experimentally produced by allowing amino acids to dehydrate on hot, dry substrates

73
Q

origin of life: protobionts

A

the precursors of cells; able to carry out chemical reactions enclosed within a border across which materials could be exchanged, but were unable to reproduce.

74
Q

origin of life: microspheres and coacervates

A

are experimentally (and abiotically) produced protobionts that have some selectively permeable qualities

75
Q

origin of life: endosymbiotic theory

A

eukaryotic cells originated from a mutually beneficial association (symbiosis) among various kinds of prokaryotes. Specifically, mitochondria, chloroplasts, and other organelles established residence inside another prokaryote, producing a eukaryote

76
Q

What is evidence for the endosymbiotic theory?

A
  1. mitochondria and chloroplasts posses their own DNA. The DNA is circular and “naked” (w/o proteins) as is the DNA of bacteria and cyanobacteria
  2. Ribosomes of mitochondria and chloroplasts resemble those of bacteria and cyanobacteria, with respect to size and nucleotide sequence
  3. Mitochondria and chlorplasts reproduce independently of their eukaryotic host cell by a process similar to the binary fission of bacteria.
  4. Mitochondria and chloroplasts have 2 membranes (both phospholipid bilayers). The 2nd membrane could have been acquired when the introduced prokaryote is surrounded , in endocytosis fashion, by a vesicle produced by the host prokaryote.
  5. The thylakoid membranes of chloroplasts resemble the photosynthetic membranes of cyanobacteria
77
Q

(evidence for evolution) Comparative biochemistry

A

organisms w/ common ancestor = common biochemical pathways

78
Q

neutral variation

A

variation w/o selective value (e.g. fingerprints in humans)

79
Q

geographic variation

A

variation of a species dependent on climate or geographic conditions. A graded variation of a phenotype due to this is known as a cline; variation from north/south environments is a north-south cline

80
Q

Universe age

A

12-15 billion years old

81
Q

solar system age

A

4.6 billion yrs old

82
Q

earth age

A

4.5 billion yrs old

83
Q

fossil age

A

3.6 billion yrs old

84
Q

photosynthetic bacteria age

A

2.3 billion yrs old

85
Q

eukaryotic bacteria age

A

1.5 billion yrs old

86
Q

Miller and Urey

A

used ammonia, methane, water and hydrogen sealed + simulated lightning => saw several organic molecules, AA’s, starting materials, but no NAs!

87
Q

What was the modern atmosphere like?

A

78% nitrogen, 21% oxygen, 1% argon, then a lot of other less important gases

88
Q

vestigial structures

A

structures that appear to be useless but had ancestral function; ex humans (appendix and tail), horses (splints), python (legs reduced to bones)

89
Q

mullerian mimicry

A

2 or more harmful species that are not closely related, and share 1 or more common predators, have come to mimic each other’s warning signals

90
Q

batesian mimicry

A

deceptive; harmless species has evolved to imitate the warning signals of a harmful species directed at a common predator

91
Q

gene pool

A

all the alleles for any given trait in the populaiton

92
Q

anagenesis/phyletic evolution

A

one species replaces another, straight path evolution

93
Q

cladogenesis/branching evolution

A

new species branches out from parent species

94
Q

deme

A

small local population (e.g. all the beavers along specific portion of a river)

95
Q

general categories of living organisms

A

autotrophic anaerbones (chemosynthetic bacteria), autotrophic aerobes (green plants, photoplankton), heterotrophic anaerobes (yeast), heterotrophic aerobes (amoebas, earthworms, humans)

96
Q

symbiosis

A

relationship between 2 species. Can be: mutualism (beneficial/beneficial), commensalism (beneficial/neutral), parasitism (beneficial/detrimental)

DAT (18 decks)

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