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BIOL 107 > Chapter 11: Evolution and Its Processes > Flashcards

Chapter 11: Evolution and Its Processes Flashcards

1
Q

define evolution

A
  • descent with modification
  • any change in heritable traits within a population across a generation
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2
Q

define natural selection

A
  • mechanism to explain evolution
  • differential reproductive success
  • process when population’s heritable variations are exposed to environmental factors that favor success of some over others
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3
Q

define variation

A
  • differences in a population
  • must have some genetic basis
  • mutations, crossing over/independent assortment during meiosis, sexual reproduction
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4
Q

define adaptation

A
  • match of organism to environment
  • aids in survival and reproduction of organism in its present environment
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5
Q

define divergent evolution

A
  • structures that evolve from a common ancestor
  • wings of a hummingbird and ostrich
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6
Q

define convergent evolution

A
  • structures that did not evolve from a common ancestor; evolved independently
  • wings of bats and insects
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7
Q

define homologous structure

A
  • result of divergent evolution
  • structure from common ancestor
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8
Q

define analogous structure

A
  • result of convergent evolution
  • structure not from common ancestor; evolved independently
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9
Q

define evolutionary theory

A
  • modern synthesis
  • genetics and evolution integrated into one theory
  • from work of Mendel and Darwin
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10
Q

define microevolution

A
  • small-scale
  • within single species
  • short period of time
  • changes in allele frequency in a population; changes phenotype
  • ex: beaks of finches after 1977 drought
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11
Q

define macroevolution

A
  • large-scale
  • long period of time
  • formation of new species and higher taxonomic groups
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12
Q

define population genetics

A
  • field of study examining what happens to alleles in a population
  • defines evolution in terms of genetic change that underlies phenotypic change; changes in frequency of an allele
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13
Q

define allele frequency

A
  • describes how common an allele is in a population
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14
Q

define Hardy-Weinberg equilibrium

A
  • a population allele and genotypic frequencies are stable unless some kind of evolution force is acting on the population
  • if no factors are acting on a population, the allele frequencies with remain constant
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15
Q

how old is the idea of evolution

A
  • very old: B.C., pre-Socratic era
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16
Q

what were Plato’s ideas on evolution

A
  • thought species were static and unchanging
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17
Q

describe the ideas of evolution in the 18th century

A
  • accepted idea of extinct species
  • idea that geology of the planet was consequence of catastrophic events OR geological change occurred gradually
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18
Q

describe Lamarck’s idea of evolution

A
  • inheritance of acquired characteristics
  • if an organism changes to adapt to its environment then those changes will be passed onto offspring
  • now known to be incorrect
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19
Q

how did August Weissman disprove Lamarck’s idea of the mechanism of evolution

A
  • cut tails off 22 generations of mice
  • observed that all offspring had tails
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20
Q

how did Charles Darwin and Alfred Wallace create a new idea on the mechnaism of evolution

A
  • both went to different parts of the world and observed species on separate islands
  • separately and simultaneously explained natural selection
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21
Q

what is the actual mechanism for evolution and who discovered it

A
  • natural selection
  • Darwin and Wallace
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22
Q

what animal did Charles Darwin study to determine natural selection as the mechanism of evolution

A
  • finches of the Galapagos islands
  • observed how beak shape adapted to different food sources
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23
Q

what three principles of nature are needed for natural selection to occur

A
  • individuals have to vary within a species
  • variation has to be heritable
  • organisms have to have more offspring than resources can support
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24
Q

what are the consequences of natural selection

A
  • more likely to survive
  • higher reproduction rates
  • traits passed to offspring; greater proportions in following generation
  • changes in population over generations
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25
Q

do individuals evolve

A
  • no
  • populations of organisms evolve
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26
Q

is evolution always a result of natural selection

A
  • no
  • many other driving factors including mutations, genetic drift, and migration
27
Q

describe how to 1977 drought affected finch beak length

A
  • 1976: smaller beaks
  • 1978: larger beaks
28
Q

are mutations always bad

A
  • no
  • may have no effect, negative effect, or positive effect
29
Q

why are the same traits not always advantageous in every population or throughout time

A
  • environmental conditions favor certain traits
  • different conditions for different organisms
  • conditions change over time
30
Q

is the dominant allele more frequent

A
  • not always
31
Q

why might a dominant allele not increase in frequency in a population until it eliminated all other alleles

A
  • recessive allele is advantageous in the environment
32
Q

what are the 5 assumptions of Hardy-Weinberg equilibrium

A
  • no mutations
  • no selection pressures
  • no gene flow (migration)
  • infinite population size
  • random mating
33
Q

what do the p and q represent in Hardy-Weinberg equilibrium equations

A
  • p=allele frequency of dominant allele
  • q=allele frequency of recessive allele
34
Q

what are the 4 equations in the Hardy-Weinberg equilibrium

A
  • p + q = 1
  • p^2 and q^2 = frequency of each homozygote
  • 2pq = frequency of heterozygote
  • p^2 + 2pq + q^2 = 1
35
Q

what 5 evolutionary forces disrupt the Hardy-Weinberg equilibrium

A
  • natural selection
  • mutations
  • genetic drift
  • migration
  • non-random mating
36
Q

define mutation

A
  • source of new alleles
  • change in allele frequency is very small
  • new allele may be selected for, selected against, or selectively neutral
  • ultimate source of variation
37
Q

define genetic drift

A
  • effect of chance
  • mortality of individual, fidning a mate, which gametes are fertilized
  • most important in small populations
  • influenced by bottleneck effect and founder effect
38
Q

define bottleneck effect

A
  • influences genetic drift
  • disaster reduces population size
  • genetic makeup of survivors becomes genetic makeup of entire population
39
Q

define founder effect

A
  • influences genetic drift
  • small group leaves to start new population in a new location
  • population gets divided by physical barrier
40
Q

define gene flow/migration

A
  • flow of alleles in and out of a population resulting from the migration of individuals
  • some population are fairly stable, others experience more flux
41
Q

what do fossils do for biology

A
  • show evolution of form through time
  • sold evidence that organisms from the past differ from those today
42
Q

define vestigial structures

A
  • structures that exist but have no apparent function
  • leftover form past ancestor
  • legs in snakes, wings in flightless birds
43
Q

define convergence of form

A
  • similar characteristics in organisms in similar environments
  • occurs from similar selection pressure NOT common ancestry
  • fox and birds having temporary white covering during the winter
44
Q

define embryology

A
  • study of the development of the anatomy of an organism to its adult form
  • provides evidence of relatedness between now widely divergent groups of organisms: gill slits and tail in early development
45
Q

define biogeography

A
  • geographic distribution of organisms on the planet
  • follows patterns of evolution and movement of tectonic plates
46
Q

examples of biogeography

A
  • islands created from tectonic plate movement and species diverge
  • diversification of marsupials in australia
47
Q

define species

A
  • group of actually or potentially interbreeding individuals
  • must be able to mate and produce fertile offspring
48
Q

define allopatric speciation

A
  • speciation in other homelands
  • geographic separation
  • two kinds: dispersal and vicariance
49
Q

define sympatric speciation

A
  • speciation in the same homeland
  • occurring within parents species while remaining in one location
  • two mechanisms: autopolyploidy and alloploidy
50
Q

define adaptive radiation

A
  • populations disperse through an area and each finds a distinct niche or habitat
  • multiple speciation events originating from a single species
51
Q

define autopolyploidy

A
  • mechanism of sympatric speciation
  • error in meiosis where all chromosomes move into one cell instead of separating
  • common in plants
52
Q

define alloploidy

A
  • mechanism of sympatric speciation
  • results when two species mate to produce viable offspring
  • occurs in cultivated forms of wheat, cotton, and tobacco
53
Q

define dispersal allopatric speciation

A
  • when few members of a species move to a new location
54
Q

define vicariance allopatric speciation

A
  • when a natural situation arises to physically divide the organisms
55
Q

describe the process of speciation with geographic separation

A
  • initial population with relatively homogenous gene pool
  • populations are separated and alleles aren’t free-flowing
  • populations evolve as different alleles become predominant and new alleles arise through mutations
  • divergence may affect reproduction and create speciation
56
Q

describe an example of speciation without geographic separation in fish in a lake

A
  • fish live in a lake
  • competition for food increases as population grows
  • some fish are able to feed of another resource
  • those fish breed with each other
  • eventually, speciation may occur
57
Q

what are the 6 misconceptions of evolution

A
  • evolution is just a theory
  • individuals evolve
  • evolution explains the origin of life
  • organisms evolve on purpose
  • evolution is controversial among scientists
  • other theories should be taught
58
Q

describe this misconception of evolution: evolution is just a theory

A
  • there is lots of evidence to support evolution
  • is a scientific theory, not everyday definition of theory
59
Q

describe this misconception of evolution: individuals evolve

A
  • individuals are born with their genes
  • individual changing over time in development, not changing genes
  • evolution is change in genetic composition of POPULATIONS over time
60
Q

describe this misconception of evolution: evolution explains the origin of life

A
  • no, just explains how populations change over time
61
Q

describe this misconception of evolution: organisms evolve on purpsoe

A
  • evolution in response to environment changing
  • not intentional
  • variation already exists within the population
62
Q

describe this misconception of evolution: evolution is controversial among scientists

A
  • was only controversial in the 1860s
  • scientific arguments were resolved, religious arguments still persist although many denominations accept evolution and their own theories
  • 97% of scientists believe species evolve
63
Q

describe this misconception of evolution: other theories should be taught

A
  • no other theories are scientific

BIOL 107 (18 decks)

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