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

Chapter 11: Evolution and Its Processes Flashcards

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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
do individuals evolve
- no - populations of organisms evolve
26
is evolution always a result of natural selection
- no - many other driving factors including mutations, genetic drift, and migration
27
describe how to 1977 drought affected finch beak length
- 1976: smaller beaks - 1978: larger beaks
28
are mutations always bad
- no - may have no effect, negative effect, or positive effect
29
why are the same traits not always advantageous in every population or throughout time
- environmental conditions favor certain traits - different conditions for different organisms - conditions change over time
30
is the dominant allele more frequent
- not always
31
why might a dominant allele not increase in frequency in a population until it eliminated all other alleles
- recessive allele is advantageous in the environment
32
what are the 5 assumptions of Hardy-Weinberg equilibrium
- no mutations - no selection pressures - no gene flow (migration) - infinite population size - random mating
33
what do the p and q represent in Hardy-Weinberg equilibrium equations
- p=allele frequency of dominant allele - q=allele frequency of recessive allele
34
what are the 4 equations in the Hardy-Weinberg equilibrium
- p + q = 1 - p^2 and q^2 = frequency of each homozygote - 2pq = frequency of heterozygote - p^2 + 2pq + q^2 = 1
35
what 5 evolutionary forces disrupt the Hardy-Weinberg equilibrium
- natural selection - mutations - genetic drift - migration - non-random mating
36
define mutation
- 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
define genetic drift
- 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
define bottleneck effect
- influences genetic drift - disaster reduces population size - genetic makeup of survivors becomes genetic makeup of entire population
39
define founder effect
- influences genetic drift - small group leaves to start new population in a new location - population gets divided by physical barrier
40
define gene flow/migration
- 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
what do fossils do for biology
- show evolution of form through time - sold evidence that organisms from the past differ from those today
42
define vestigial structures
- structures that exist but have no apparent function - leftover form past ancestor - legs in snakes, wings in flightless birds
43
define convergence of form
- 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
define embryology
- 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
define biogeography
- geographic distribution of organisms on the planet - follows patterns of evolution and movement of tectonic plates
46
examples of biogeography
- islands created from tectonic plate movement and species diverge - diversification of marsupials in australia
47
define species
- group of actually or potentially interbreeding individuals - must be able to mate and produce fertile offspring
48
define allopatric speciation
- speciation in other homelands - geographic separation - two kinds: dispersal and vicariance
49
define sympatric speciation
- speciation in the same homeland - occurring within parents species while remaining in one location - two mechanisms: autopolyploidy and alloploidy
50
define adaptive radiation
- populations disperse through an area and each finds a distinct niche or habitat - multiple speciation events originating from a single species
51
define autopolyploidy
- mechanism of sympatric speciation - error in meiosis where all chromosomes move into one cell instead of separating - common in plants
52
define alloploidy
- mechanism of sympatric speciation - results when two species mate to produce viable offspring - occurs in cultivated forms of wheat, cotton, and tobacco
53
define dispersal allopatric speciation
- when few members of a species move to a new location
54
define vicariance allopatric speciation
- when a natural situation arises to physically divide the organisms
55
describe the process of speciation with geographic separation
- 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
describe an example of speciation without geographic separation in fish in a lake
- 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
what are the 6 misconceptions of evolution
- 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
describe this misconception of evolution: evolution is just a theory
- there is lots of evidence to support evolution - is a scientific theory, not everyday definition of theory
59
describe this misconception of evolution: individuals evolve
- 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
describe this misconception of evolution: evolution explains the origin of life
- no, just explains how populations change over time
61
describe this misconception of evolution: organisms evolve on purpsoe
- evolution in response to environment changing - not intentional - variation already exists within the population
62
describe this misconception of evolution: evolution is controversial among scientists
- 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
describe this misconception of evolution: other theories should be taught
- no other theories are scientific
BIOL 107
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