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DAT > ch.6 evolution, ecology > Flashcards

ch.6 evolution, ecology Flashcards

1
Q

evolution

A

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

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2
Q

microevolution

A

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

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3
Q

macroevolution

A

the 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). these patterns can be used to establish a phylogenetic tree

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4
Q

Lamarck Theory: use and disuse

A

body parts can develop with increased usage and unused parts are weakened

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5
Q

Lamarck Theory: inheritance of acquired characteristics

A

body features acquired during one’s lifetime can be passed down to offspring.

this is incorrect, since only changes in genetic material of cells can be passed down to offspring

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6
Q

natural transformation of species

A

organisms produce offspring with changes, transforming each consecutive generation to be slightly more complex. Lamarck did not believe in extinction or the splitting of creating more species. This is an incorrect idea!

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7
Q

natural selection

A

survival of the fittest without any luck. allele frequencies increase or decrease in order to adapt to the environment

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8
Q

Neo-Darwinism

A

synthetic theory of evolution that combines Darwin’s theory with the influence of genetics that Darwin was unaware of to propose mechanisms responsible for evolutionary patterns

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9
Q

descent with modification

A

coined by Darwin, this occurs via natural selection. over time and generations, traits providing reproductive advantage becomes more common within the populaion

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10
Q

paleontology

A

fossils reveal prehistoric existence of extinct species, and are often found in sediment layers. deepest fossils represent the oldest specimens. large, rapid changes produce new species

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11
Q

fossil types

A

actual remains, petrification, imprints, molds, and casts

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12
Q

biogeography

A

the geography that describes the distribution of species. unrelated species in different regions of the world look alike when found in a similar environment. the supercontinent Pangea slowly broke apart to 7 continents due to continental drift

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13
Q

embryology

A

similar stages of development among related species establishes evolutionary relationships. gill slits and tails are found in fish, chickens, pigs, and human embryos

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14
Q

ontogeny

A

the development of an organism

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15
Q

phylogeny

A

the evolutionary development and diversification of a species

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16
Q

homologous structures

A

body parts that resemble one another between different species that descended from a common ancestor. e.g., bat forelimbs vs. bird forelimbs

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17
Q

analogous structures

A

body parts that resemble one another between different species that evolved independently. they have similar structures as adaptations to similar environments. these structures are also called homoplasies. e.g., bat wings vs. bee wings

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18
Q

molecular biology

A

this field examines nucleotide and amino acid sequences of DNA and proteins from different species. more than 98% of nucleotide sequences in humans and chimpanzees are identical. amino acids in the protein cytochrome c are often compared

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19
Q

comparative biochemistry

A

organisms with a common ancestor mean they have common biochemical pathways

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20
Q

stabilizing selection

A

the bell curve favors an intermediate, like how the average height in humans is in the middle

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21
Q

directional selection

A

the favoring of traits that is at one extreme of the range. traits at opposite extremes are selected against

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22
Q

industrial selection

A

the selection of dark-colored, melanic, varieties in various species of moths, like the peppered moth, as a result of industrial pollution. this is a specific type of directional selection

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23
Q

disruptive selection

A

this selection occurs when the environment favors extreme or unusual traits while selecting against common traits. for example, a certain environment may favor short and tall heights while the average height is selected against

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24
Q

sexual selection

A

the differential mating of males or females in a population

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25
Q

intersexual selection

A

females choose superior males, which increases the fitness of the offspring. because females invest more energy into their offspring, they want to maximize the quality of their offspring by picking fit males

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26
Q

intrasexual selection

A

when males compete and fight with other males for better mating opportunities. males increase fitness of offspring by maximizing quantity. intrasexual selection favors traits like musculature, horns, large stature etc.

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27
Q

sexual dimorphism

A

the differences in appearance of males and females, which is a form of disruptive selection. this occurs because female choice leads to traits and behaviors in males that are favorable to females. male traits like colorful plumage or elaborate mating behavior will be selected for by females

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28
Q

artificial selection

A

this is a form of directional selection carried out by humans when they breed favorable traits, and it not natural selection

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29
Q

mutation

A

new alleles could be introduced to the population with genetic mutations

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30
Q

sexual reproduction

A

genetic recombination such as crossing over, independent assortment, and random joining of gametes can occur during sexual reproduction

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31
Q

diploidy

A

diploid organisms have two copies of each chromosome. in heterozygous conditions, the recessive allele is stored for later generations, and thus more variations are maintained in the gene pool

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32
Q

outbreeding

A

mating with unrelated partners results in mixing of different alleles and creating new allele combinations

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33
Q

hybrid vigor (heterosis)

A

the superior quality of offspring resulting from crosses between two different inbred strains, species, or varieties of organisms. hybrid superior quality results from reducing deleterious recessive homozygous conditions and increasing heterozygous advantage

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34
Q

frequency-dependent selection (minority advantage)

A

occurs when least common phenotypes have a selective advantage. common phenotypes are selected against. rare phenotypes will increase in frequency and will then be selected against, repeating the cycle. for example, predators use search images of common phenotypes and find prey, allowing prey with rare phenotypes to escape. the rare prey phenotype eventually becomes common, and then the cycle repeats

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35
Q

neutral variation

A

these are variations that are passed down without any selective value, such as fingerprints in humans

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36
Q

geographic variation

A

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

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37
Q

natural selection

A

the increase and decrease of allele frequencies due to adaptations to the environment

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38
Q

gene flow

A

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

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39
Q

genetic drift

A

the random increase and decrease of an allele by chance. genetic drift has a larger effect on small populations

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40
Q

founder effect

A

when a small group of individuals migrate to a new location, the gene pool of the small group will be less than the original population. after successive generations, the genetic makeup will be unique from the original population

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41
Q

bottleneck effect

A

occurs when the population undergoes a dramatic decrease in size due to natural catastrophes or other events. the population is now vulnerable to genetic drift, and the gene pool is much smaller

42
Q

nonrandom mating

A

individuals choose mates based upon their particular traits

inbreeding - individuals mate with relatives, this changes genotype proportions but not allele frequency
sexual selection - females choose males based on superior traits

43
Q

Hardy-Weinberg equation

A

p2 + 2pq + q2 = 1
p+q=1

44
Q

requirements to be in Hardy-Weinberg equilibrium

A
  1. no mutations
  2. no natural selection - the environment is not impacting allele frequencies, so traits are neutral
  3. no gene flow
  4. large populations - this decreases the effects of genetic drift
  5. random mating
45
Q

speciation

A

the formation of new species. when gene flow ceases, or is interrupted, between two sections of a population, speciation begins

46
Q

species

A

a group of individuals capable of interbreeding

47
Q

allopatric speciation

A

this speciation occurs when the population is divided by a geographic barrier. interbreeding between two resulting populations is prevented as a result. the gene frequencies in the population can now diverge due to natural selection, mutation, and genetic drift. if the gene pool sufficiently diverges, the separated populations will not interbreed when the barrier is removed. if they cannot interbreed, that means a new species has formed

48
Q

dispersal

A

the group is isolated by being physically removed from the original location of the larger group

49
Q

vicariance

A

the group is isolated by a geographic barrier but is in the same overall location of the larger group

50
Q

sympatric speciation

A

this is the formation of new species without the presence of geographic barriers

51
Q

balanced polymorphism

A

natural selection due to polymorphism

ex: only some insects can camouflage, the ones that cannot will be eaten. only insects with the advanatageous color will mate bc they survive, and are now isolated from other subpopulations

52
Q

polyploidy

A

possessing more than the normal two sets of chromosomes, such as 3n or 4n. this can lead to reproductive isolation, such as in plants

53
Q

autopolyploidy

A

when an organism has more than two sets of chromosomes, both of which are from the same parental species

54
Q

allopolyploidy

A

when an organism has more than two sets of chromosomes, but they come from different species

55
Q

hybridization

A

two different closely related species mate and produce a hybrid along a geographic boundary called a hybrid zone

can result in more genetic variation. this means the hybrid can live beyond the range of either parents

56
Q

reinforcement

A

hybrids are less fit than either purebred species. the species continue to diverge until hybridization can no longer occur

57
Q

fusion

A

reproductive barriers weaken until the hybrid and purebred species become one

58
Q

stability

A

fit hybrids continue to be produced

59
Q

adaptive radiation

A

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

60
Q

prezygotic isolation

A

prevents fertilization before mating is attempted, and so a zygote is not formed

61
Q

habitat isolation

A

species do not encounter each other because they live in different habitats, even if they live in the same geographical area

62
Q

temporal isolation

A

species reproduce at different seasons/times

63
Q

behavioral isolation

A

some species will not reproduce with each other if they do not perform the correct courtship rituals

64
Q

mechanical isolation

A

occurs when male and female genitalia are not compatible

65
Q

gametic isolation

A

male and female gametes do not recognize each other. the male gametes also may not survive in the environment of the female gametes

66
Q

postzygotic isolation

A

if a zygote does form

67
Q

hybrid inviability

A

the zygote fails to develop properly and dies before reaching reproductive maturity

68
Q

hybrid sterility

A

hybrids become functional adults but cannot reproduce

69
Q

hybrid breakdown

A

hybrids produce offspring that have reduced viability/fertility. the hybrid’s children cannot reproduce

70
Q

divergent evolution

A

this type of evolution occurs when two or more species that originated from a common ancestor become increasingly different over time as a result of speciation

71
Q

convergent evolution

A

occurs when two unrelated species evolve to share more similar traits due to adapting to a similar environment (analogous traits)

72
Q

parallel evolution

A

occurs when two unrelated species make similar evolutionary changes after their divergence from a common ancestor

73
Q

coevolution

A

occurs between two species. each causes the other one to evolve, which results in the evolution of both species. an example of this is the coevolution of predators and prey, where the evolution of a more effective predator will cause the prey to evolve better ways to defend itself

74
Q

phyletic gradualism

A

this theory says that evolution occurs by the gradual accumulation of small changes. however, this is unlikely to be valid because intermediate stages of evolution are missing in the fossil record

75
Q

punctuated equilibrium

A

this theory says that evolutionary history consists of geologically long periods of stasis (stability) with little or no evolution follows by geologically short periods of rapid evolution. absence of fossils revealing intermediate stages of evolution is considered data that confirms rapid evolutionary events

76
Q

Oparin & Haldane

A

these scientists proposed the organic soup theory. they said that if there was O2 in the primordial atmosphere, no organic molecules would have formed because oxygen is very reactive. Oparin’s hypothesis was that the early Earth’s environment was reducing which provides the chemical requirements to produce complex molecules from simple building blocks. an oxidizing environment would have broken the complex molecules apart

77
Q

Stanley Miller

A

testes Oparin’s theory and produced organic molecules. Miller & Urey sealed ammonia, water, methane, and hydrogen in a flask and simulated lightning; they created a simulated environment of the primordial Earth. the experiement produced several organic molecules, amino acids, and starting materials. however, no nucleic acids were made!

78
Q

vestigial structures

A

appear ti be useless but had ancestral function. for example, humans have vestigial appendixes and tails, horses have vestigial splints, and pythons have vestigial reduced leg bones

79
Q

Mullerian mimicry

A

two or more harmful species that are not closely related but share one or more common predators, have come to mimic each other’s warning signals

80
Q

Batesian mimicry

A

this is slightly different from Mullerian mimicry in that a harmless species has evolved to imitate the warning signals of a harmful species directed at a common predator

81
Q

gene pool

A

all the alleles for any given trait in the population

82
Q

parapatric speciation

A

occurs without a geographic barrier, so the population is continuous, but it still does not mate randomly. individuals more likely to mate with geographic neighbors than with an individual farther out, so divergence may happen due to reduced gene flow and because of varying selection pressures across the population’s range. a population may occupy different niches that are adjacent and not isolated, so parapatric speciation could occur

83
Q

peripatric speciation

A

similar to allopatric speciation in that a population is isolated and prevented from exchanging genes from the “main” one, but one of the populations is much smaller than the other, so it is subject to accelerated genetic drift along with differing selection pressures

84
Q

anagenesis/phyletic evolution

A

the gradual evolution of a species without any branching; it is a straight path of evolution

85
Q

cladistics

A

a method of classification according to the proportion of measurable characteristics held in common between two organisms. the more characteristics they share, the more recently they diverged from common ancestor

86
Q

clade

A

a group of species that include a common ancestor and all of its descendants. a clade is also known as a monophylum

87
Q

sere

A

a particular stage of an ecosystem

88
Q

mold

A

an organic matter that leaves an impression in rocks or in inorganic matter. later, the organic matter decays and leaves a negative impression

89
Q

cast

A

a type of fossil formed when mold is filled in

90
Q

deme

A

a small local population of the same species that regularly interbreed. for example, all the beavers along a specific portion of a river

91
Q

autotrophic anaerobes

A

chemosynthetic bacteria

92
Q

autotrophic aerobes

A

green plants and photoplankton

93
Q

heterotrophic anaerobes

A

yeast

94
Q

heterotrophic aerobes

A

amoebas, earthworms, and humans

95
Q

symbiosis

A

a relationship between two species that can be:
1. mutualistic - beneficial to both species
2. commensalism - beneficial to one species and neutral to the other
3. parasitism - beneficial to one species but detrimental to the other

96
Q

synapomorphies

A

shared traits derived from an evolutionary ancestor common to all members of a group

97
Q

analogous traits

A

similar characteristics resulting from convergent evolution, therefore they are not derived from a common ancestor

98
Q

law of parsimony

A

this is also known as Occam’s Razor, which states that the simplest explanation is most likely correct. phylogenetic trees are constructed using the Law of Parsimony. the fewest number of changes with respect to synapomorphies is likely the most correct representation of reality

99
Q

monophyletic

A

the ancestral species and all its descendants

100
Q

paraphyletic

A

the ancestral species and some but not all descendants

DAT (18 decks)

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