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biology exam > evolution > Flashcards

evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is evolution

A

process of genetic change in a population over time

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2
Q

Jean Baptiste Lemarck

A

-Inheritance of acquired characteristics: passed on to its offsprings
-Use and Disuse: body parts not used would be lost and disappear
-THEROY: giraffe’s long neck
Giraffes stretched necks to eat from tall trees, this trait passed onto generations

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3
Q

Charles Darwin

A

-Travelled on HMS beagle, mapped South American Coast
-Explored regions and collected samples (plants, animals, rocks, fossils) (flora and fauna)
-Some animals of extinct animals looked similar to living animals
-Animals on Galapagos Islands resembled animals observed on South American Coast

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4
Q

what is an adaptation

A

structure, behaviour, or physiological process that helps an organism survive and reproduce in a specific environment

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5
Q

structural adaptation

A

physical features
ex: camouflage, mimicry, webbed feet
- mimicry: resembles a harmful species
- camouflage: allows organisms to blend with surroundings

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6
Q

physical adaptation

A

internal and cellular features that helps them to survive in environment
ex: toxins produced by plants

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7
Q

behaviour adaptation

A

actions of organism that helps them to survive in environment
ex: hibernation, birds migrating south
-hibernation: reduce metabolism to save energy and survive harsh winters
ex: ground hog

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8
Q

what is natural selection

A

process of change in the characteristics of a population of organisms over generations

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9
Q

what is artificial selection

A

describes changes to a population caused by selective breeding by humans
Ex: cats bred for appearance

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10
Q

what is sexual selection

A

natural selection for mating based on competition between males and choices made by females

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11
Q

what are some of the historical contributions that led to the idea of evolution

A
  • animals observed on the Galapagos Islands resembled animals observed on the South American coast by Darwin
  • discovery of fossil bones from large extinct mammals
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12
Q

peppered moth study

A
  • would camouflage in trees covered in lichen, prey for birds
  • air pollution from new factories killed the lichen and soot covered the trees
  • moths that survived long enough to reproduce were able to pass on genes to their offspring
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13
Q

what is a population

A

consists of all the members of a species that live in an area at a certain time

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14
Q

what is allele frequency

A

number of times an allele occurs in a gene pool compared to the number in the pool for the same gene

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15
Q

what is gene flow

A

net movement of alleles from one population to another

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16
Q

what is genetic drift + the two types

A

changes in allele frequency due to chance events
- FOUNDER EFFECT: individuals start and establish a new isolated population
ex: galapagos islands
- BOTTLENECK EFFECT: change in gene pool resulting from rapid decrease in population size
ex: elephant seals due to overhunting

17
Q

what are the three types of natural selection (know graphs)

A
  1. STABILIZING SELECTION: favours intermediate phenotypes and acts against extreme phenotypes (narrower range)
    - ex: babies birth weight
  2. DIRECTIONAL SELECTION: favours phenotypes at one extreme over another, results in shifted range of phenotypes
    - ex: peppered moths
  3. DISRUPTIVE SELECTION: favours both extremes rather than intermediate phenotypes, results in split gene pool
    - ex: african finches
    (know graphs for each)
18
Q

analogous vs. homologous structures

A

ANALOGOUS: similar structure but may have different functions
ex: vertebrate forelimbs in birds, whales
HOMOLOGOUS: similar function but different structures
ex: birds and bats

19
Q

what is speciation
macroevolution vs. microevolution

A

MACRO: changes occur over long period of time
MICRO: change in gene frequencies within a population over time

20
Q

pre-zygotic mechanisms

A

prevention of mating
1. BEHAVIOURAL ISOLATION: behaviour that prevents interbreeding with closely related species
- ex: mating rituals
2. HABITAT ISOLATION:s pecies in same area occupy different habitats, rarely encounter each other
- ex: garter snakes in water and meadows
3. TEMPORAL ISOLATION: species kept separate due to timing barriers, mate at different times (seasons, years, etc.)
- ex: flowering
prevention of fertilization
4. MECHANICAL ISOLATION: related species anatomically different, can’t mate
- ex: variations in flower structure prevent pollination
5. GAMETIC ISOLATION: sperm can’t reach or fertilize egg
- ex: plants may land on stigma- fertilization doesn’t occur

21
Q

post-zygotic mechanisms

A
  1. HYBRID INVIABILITY: develops but can’t survive to maturity
    - ex: cotton plants- produce weak and sterile seeds
  2. HYBRID INFERTILITY: two species can mate but hybrid is sterile and can’t reproduce
    - ex: horse (female) and donkey (male) -> mule (sterile)
  3. ZYGOTE MORTALITY: genetic differences may stop development of zygote
    - ex: sheep and goat hybrids -> fertilization occurs but zygote doesn’t survive
22
Q

allopatric speciation

A

populations separated by a geographical barrier and diverge genetically
ex: lava flow, water

23
Q

sympatric speciation

A

populations within same geographical area diverge genetically
ex: polyploidy- results in extra chromosomes due to error in cell division

24
Q

adaptive radiation

A

diversification of a common ancestral species into a variety of differently adapted species
ex: galapagos islands

25
Q

divergent evolution

A

occurs when populations adapt to different environmental conditions, diverge and become distinct
- common ancestor
ex: adaptive radiation

26
Q

convergent evolution

A

occurs when unrelated species occupy similar environments in different parts of the world
- no common ancestor
ex: birds and bats have wings

27
Q

gradualism hypothesis

A

small, adaptive changes gradually accumulate over time
- fossils rarely reveal gradual transition

28
Q

punctuate equilibrium hypothesis

A

interrupted by periods of divergence
- supported by fossil evidence

biology exam (11 decks)

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