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DAT > Biolopy - Chapter 13: Evolution > Flashcards

Biolopy - Chapter 13: Evolution Flashcards

1
Q

Evolution

A
  • Gradual development and change of heritable traits (allele frequencies) in populations over successive generations
  • Increases biodiversity
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2
Q

5 Evidence of Evolution

A

1) Paleontology (dinosaurs)
2) Biogeography evidence
3) Embryology (early stage, we are all goo)
4) Comparative Anatomy (homologous/analogous/vestigial)
5) Biochemical methods (common conserved DNA)

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3
Q

Homologous structures

A
  • May or may not have perform the same function but have common ancestor
  • e.g. forearm of bird and human
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4
Q

Analogous structures

A
  • Same function, not have a common ancestor

- e.g. bird and bat wings

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5
Q

Vestigial structures

A

-serve no purpose but are homologous to functional structures in other organisms

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6
Q

Natural Selection

A

-gradual, non-random process where allele frequencies change as a result of environmental interaction

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7
Q

Survival of the fittest

A
  • occurs as individuals with greatest fitness have greatest success to pass on more DNA to future generations compared to less fit parent
  • leads to the evolution of the population, not individual
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8
Q

4 Requirements for Natural Selection

A

1) Competition for survival
2) Variation in traits
3) Heritable traits
4) Variation in traits must be significant for reproduction/survival

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9
Q

Stabilizing Selection

A
  • Bell curve

- mainstream (average) is favored

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10
Q

Directional Selection

A

-one extreme favored

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11
Q

Disruptive Selection

A

-rare traits are favored, mainstream is not

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12
Q

Sexual Selection

A
  • non-randoming mating between males and females
  • females favor high quality offspring
  • males prefer high quanitity of partners to increase # of offspring
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13
Q

Artificial Selection

A

this is how we got pugs :((

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14
Q

Hardy-Weinberg Purpose

A
  • calculates genetic frequency during genetic equilibrium, where no change in gene frequencies occur)
  • the population is under Hardy-Weinberg Equilibrium when both factors are true
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15
Q

Hardy-Weinberg Equilibrium Formula

A

p + q = 1

p^2 + 2pq + q^2 = 1

p: freq of homozygous dominant
2pq: freq of heterozygous
q^2: freq of homozyougs recessive

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16
Q

Requirements for Hardy-Weinberg Equilibrium

A

1) Large population
2) Random mating
3) no mutation
4) no natural selection
5) no migration (gene flow)

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17
Q

Mneumonic HW Equilibrium

A

Large, Random M&M

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18
Q

Microevolution

A

Gene frequencies change within a population over generations

19
Q

5 Factors Causing Microevolution

A

1) Genetic drift
2) Non-random mating
3) Mutations
4) Natural Selection
5) Gene Flow

20
Q

Genetic Drift

A
  • allele frequencies change by chance
    1) Bottleneck Effect: smaller gene pool, some alleles may be lost
    2) Founder Effect: individuals migrate away from the population
21
Q

4 Sources of Genetic Variation

A

1) Mutation
2) Sexual Reproduction
3) Balanced Polymorphism
4) Polyploidy

22
Q

Mutation

A

Must not be fatal in order to contribute to genetic variation

23
Q

Sexual Reproduction

A
  • crossing over

- independent assortment and random joining of gametes

24
Q

Balanced Polymorphism

A
  • maintains a variety of phenotypes within a population
  • Heterozygotes advantage
  • Minority advantage
  • hybrid advantage
  • neutral variations
25
Q

Polyploidy

A
  • Plants have multiple copies of alleles

- can mask effects of harmful recessive allele

26
Q

Macroevolution

A
  • Long term and occurs at a level at or higher than species

- Species are reproductively isolated, resulting in a lack of gene flow between differing species

27
Q

Prezygotic Isolation

A
  • Prevents fertilization from occurring between species
  • includes:
  • Habitat isolation: occupying different habitats
  • Temporal isolation: reproducing at different times/seasons
  • Behavioral isolation: different courtships
  • Mechanical isolation: cannot smash genitalia together
  • Gamete isolation: gametes do not recognize/fertilize each other
28
Q

Postzygotic Isolation

A
  • backup in case hybrid zygote forms
  • hybrid mortality: different chromosome #, hybrid not viablee
  • hybrid sterility: hybrid zygote sterile
  • hybrid F2 breakdown: offspring of hybrids have decreased fitness
29
Q

Speciation

A

-how species form starting with reproductive isolation which leads to interruption of gene flow

30
Q

Allopatric Speciation

A
  • due to geographical barrier

- adaptive radiation occurs when many species arise from one ancestor as they adapt differently to their environments

31
Q

Sympatric Speciation

A
  • occurs without a geographical border
  • Balanced polymorphism: different phenotypes are isolated within the same area
  • Polyploidy: in plants results from nondisjunction during meiosis
  • Hybridization: some hybrids more fit than normal
32
Q

Theories of Macroevolution

A

1) Phyletic gradualism: evolution happened gradually via accumulation of small inteermediary changes (not likely to be true)
2) Punctuated equilibrium: short spurts of evolutionary changes during periods of stasis (supported by fossil evidence)

33
Q

Divergent Evolution

A

Diverge from common ancestor

34
Q

Convergent Evolution (Homoplasy)

A

Unrelated species adapt to similar environments and develop analogous structures

35
Q

Parallel Evolution

A

Diverge from common ancestor but undergo similar changes

36
Q

Coevolution

A

Two species impart selective pressure on each other

-Camouflage, aposematic coloration, mimicry

37
Q

Types of Mimicry

A

1) Batesian mimicry: non-harmful animal resembles harmful one
2) Mullerian mimicry: two poisonous animals resemble each other to warn their predators

38
Q

Parsimony

A
  • The simpler the explanation, the better

- Trees minimizing evolutionary reversals, convergent evolution and parallel evolution are preferred

39
Q

Origins of Life Timeline (Big Bang, Earth, Prokaryotes, Eukaryotes)

A

Big Bang: 14 billion years ago
Earth: 4.5 billion years ago
Prokaryotes: 3.5 billion years ago
Eukaryotes: 2 billion yeears ago

40
Q

Earth’s Current Atmosphere

A

Nitrogen = 78%
Oygen = 21%
Argon gas = 0.9%
Trace amounts of CO2, methane, ozone

41
Q

Primordial Earth

A
  • consisted of inorganic compounds and no oxygen (reducing environment)
  • primordial sea formed when earth cooled down
  • the development of autotrophs led to the production of oxygen
42
Q

Organic “Soup” Theory

A
  • Oparin and Haldane
  • Believed that oxygen is too reactive for organic chemicals to be produced in primordial atmosphere
  • therefore, oxygen must have been lacking in primordial atmosphere
  • strong reactions (lightning, UV, volcanic heat) drove reactions that formed organic compounds
43
Q

Miller-Urey Experiment

A
  • Mimicked reducing environment proposed by Organic Soup Theory
  • inorganic compounds + no oxygen + electrodes + heat
  • Amino acids, organic acids were formed but no nucleic acids

DAT (16 decks)

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