Unit 7 - Natural Selection Flashcards

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1
Q

Evolution

A

change in the genetic makeup of a POPULATION OVER TIME

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2
Q

Natural Selection

A

process which individuals that have certain traits tend to SURVIVE AND REPRODUCE at high rates than others due to traits

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3
Q

Phenotypic variation

A

can decrease/increase fitness

DNA sequence doesn’t matter

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4
Q

Selective Pressures

A

changes in the environment

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5
Q

Heritable traits

A

from PARENT TO OFFSPRING
- sexual reproduction (crossing over, independent assortment, random fertilization)
- random mutations
- adaptations to environment

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6
Q

Ways to increase fitness

A
  • more offspring = more survive
  • successful competition for resources = increase change of survival and reproduction
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7
Q

Fitness

A

reproductive success = evolutionary fitness

more changes in the environment will lead to more evolution/adaptation

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8
Q

Artificial selection

A

selective breeding by humans to encourage a desirable trait

can increase OR decrease genetic diversity

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9
Q

Population

A

a group of individuals that are the same species, live in the same area, and interbreed to produce FERTILE offspring

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10
Q

Gene pool

A

population’s genetic makeup

all copies of every type of allele

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11
Q

Fixed allele

A

1 allele present for a particular locus (where on a chromosome a specific gene is); an allele that is the only variant that exists for that gene in a population

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12
Q

Genetic drift

A

CHANCE event that cause a change in allelic frequency from one generation to the next

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13
Q

How does genetic drift affect a population?

A
  • most affects small population
  • increased mortality and decreased reproduction (from natural disaster)
  • loss of genetic variation
  • harmful alleles become fixed

does NOT produce adaptations (random event!!)

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14
Q

Bottleneck

A

large population is significantly reduced by a non-selective disaster

ex: fire, famine, etc

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15
Q

Founder

A

a few individuals isolate and establish a new population with a different gene pool; lose genetic diversity

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16
Q

Gene Flow

A

transfer of alleles in/out of a population; migration

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17
Q

Convergent evolution

A

similar traits but unrelated lineage due to similar selective pressures/niches

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18
Q

Analogous structure

A

pairs with CONVERGENT EVOLUTION

similar structure/function with different ancestors

penguins, sharks, dolphins: light color bellies but only because they adapt that way to the environment

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19
Q

Divergent

A

accumulation of differences in groups (due to DIFFERENT ENVIRONMENTAL PRESSURES) that leads to speciation (formation of NEW SPECIEIS)

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20
Q

Homologous Structures

A

pairs with DIVERGENT EVOLUTION

common ancestor/blueprint but evolves into different structures with different functions

humans, bats, cats: same bone structures in arms with fingers due to common ancestor but now has different functions

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21
Q

Coevolution

A

2 interdependent (dependent upon one another) species influence each other’s morphology

ex: prey/predator, plant/pollinator

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22
Q

Adaptive Radiation

A

ancestral species develop into different species and fills in different environmental niches

modifies homologous structures and is due to ecological opportunity

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23
Q

Gradualism

A

evolutionary chang is slow; small genetic change favored by natural selection

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24
Q

Punctuated

A

periods of stasis (no change) to rapid development (punctuated)

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25
Q

What increases chance of survival?

A

increased variation will help populations survive in changing environmental conditions

increased variation will mean more chances for an individual to have a favorable trait

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26
Q

Phenotypic advantage

A

fitness advantage in an individual

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27
Q

Selective pressures

A

biotic/abiotic factors that influence survivability

  • availability of resources
  • predators
  • disease
  • climate
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28
Q

Environmental factors

A

trait previously suited may no longer be suited after changed environment

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29
Q

5 principles of natural selection

A
  1. variation
  2. trait must be heritable
  3. more offspring that can survive
  4. traits that increase fitness are passed down more often
  5. POPULATIONS CHANGE; not individuals
30
Q

Hardy Weinberg

A
  1. no mutations
  2. random mating
  3. no natural selection
  4. extremely large population size
  5. no gene flow
31
Q

Geographical evidence

A

characteristics of habitat or land loss

32
Q

Geological evidence

A

features of Earth overtime (fossils)

33
Q

Physical evidence

A

phenotypes/traits of species

34
Q

Biochemical evidence

A

chemical composition (molecules – DNA, proteins)

35
Q

Mathematical evidence

A

calculations, statistics, models, simulations

36
Q

Fossils

A

visual of evolutionary change over time

rate of carbon 14 decay: less carbon = older

37
Q

Comparative Morphology

A

analysis of living and extincet structures

38
Q

Embryotic Homology

A

similar embryotic development

39
Q

Vestigial Structures

A

structures that are conserved even if they are no longer used

40
Q

Molecular Homology

A

many species share similar DNA, animo acid sequences

41
Q

Biogeography

A

related organisms are different in different places due to evolving in different conditions

ex: finches in Galapagos, Pangea

42
Q

Genome Changes

A

antibiotic resistant bacteria, pathogens = new diseases

43
Q

Synapomorphy

A

derived characteristics shared by clade members

44
Q

Derived

A

similarly inherited from most recent common ancestor

45
Q

Ancestral

A

arose prior to the common ancestor

46
Q

Monophyletic

A

includes most recent common ancestor and all descendants (grandparents and all grandkids)

47
Q

Paraphyletic

A

most recent common ancestor but missing descendants (grandparents and some cousins are missing)

48
Q

Polyphyletic

A

no common ancestor but has descendants (grandparents are missing but grandchildren are there)

49
Q

Allopatric

A

physical barrier divides a population and is separated (geographic isolation)

  • prevents gene flow
  • usually caused by natural disaster
50
Q

Sympatric

A

new species evolves while still in the same geographical region as ancestral species

  • reproductively isolated; when brought back together, and are able to interbreed = they are NOT distinct species
51
Q

Prezygotic

A

prevents mating/hinders fertilization

52
Q

Habitat - Prezygotic

A

live in different areas/habitats in the same area

53
Q

Temperal - Prezygotic

A

mate at different times; time of day/year/season

54
Q

Behavioral - Prezygotic

A

different mating rituals

55
Q

Mechanical - Prezygotic

A

reproductive anatomy doesn’t fit

56
Q

Gametic - Prezygotic

A

proteins on eggs’ surface don’t allow for the egg and sperm to fuse

57
Q

Postzygotic

A

prevent hybrid zygote from developing into a fully viable and fertile adult

58
Q

Reduced viability

A

impair development/survival

59
Q

Reduced fertility

A

hybrid can develop into an adult but is sterile

60
Q

Hybrid breakdown

A

1st generation of hybrids survives and reproduces but 2nd generation is sterile

61
Q

Microevolution

A

change in allele frequency

ex: genetic drift, natural/sexual selection, gene flow

62
Q

Macroevolution

A

large evolutionary patterns

ex: adaptive radiation, mass extinction, stasis

63
Q

Human causes of extinction

A

pollution, climate change, poaching, habitat loss/destruction, invasive species

64
Q

Types of traits

A

Adaptive: increase chance of survival
Deleterious: decrease chance of survival

both depend on environment

65
Q

Directional

A

selecting for 1 EXTREME trait

66
Q

Stabilizing

A

select intermediate; AGAINST EXTREME traits

67
Q

Disruptive

A

selecting for BOTH EXTREME traits

68
Q

Sexual selection

A

chooses mate based on one/more traits; 1 sex has to compete for a mate

  • result in traits harmful to an individual; peacock big tail
68
Q

Early Life

A

synthesize organic molecules from inorganic molecules with free energy (UV, electric discharge, heat)

69
Q

RNA World Hypothesis

A

RNA was the earliest genetic material; created on primitive Earth and could self-replicate without other molecules

Primordial soup: early oceans with inorganic and simple organic molecules; formed with free nucleotides