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Flashcards in chapter 27 Deck (34):
1

Biological Evolution Lamarck

-inheritance of acquired characteristics
-giraffes had to stretch their necks to reach their food, their necks would become longer

2

Biological Evolution Darwin

-Evolution by natural selction
-Darwin invented it

3

Evidence for evolution

-fossils
-transitional forms
-homologous and analogous structures
-vestigial structures
-biochemical evidence
-homologous developmental stages
-artificial selection

4

Fossils

-hard body parts
-embedded in sedimentary rock
-deposited in strata

5

fossil mold

air space remains (jello mold)

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fossil cast

Silica fills space (like a jello 3d structure)

7

Anatomical Evidence

-transitional forms: whale: reduced hind limbs and pelvic bones; transitional links between groups

-analogous structures: evolved separately but have similar function (human eye and octopi eye) (Flipper of a dolphin and fin of a tuna)

-homologous: similarity resulting from a common ancestry but different functions (human arm, cat leg, whale fin, bat wing)

-Vestigial: something that we have but go away (human tail bone, appendix)

8

Biochemical Evidence

-DNA, ATP, Enzymes are all universal
-Gemetic code: RNA to amino acid triplets--universal
-many genes are shared by all organisms

9

Microevolution

-a change in allele frequency population over time
-populations evolve, individuals do not

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Hardy-Weinberg Equilibrium

no mutations, no genetic drift, no gene flow, random mating, no selection

-basically if we were to take out random events genetic variation will remain constant from one gen. to the next

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No mutations

-cause allele frequencies in a population
-only source of new variation
-random events

12

No genetic drift

-chance events cause allele frequencies to fluctuate
-affects smaller population more

13

bottleneck effect

-catastrophes kill large numbers of individuals-->loss of genetic diversity
-take out more of the Dominant genes
-recessive allele more present

14

Founder effect

-few individuals colonize an island or other new habitat
-polydactylyl in amish

15

No gene Flow

-movement of alleles between populations (migrations)
-gene flow mixes genetic diversity
-Makes gene pools of two or more populations SIMILAR

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Random mating

-individuals don't choose their mates
-random mating is never observed in natural population

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No selection

-Heritable variation
-over-reproudction
-competition
-differ in reproductive success and fitness
-adaptation

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Types of natural selection

stabilizing, directional, disruptive

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Stabilizing

select against extreme
-picking recessive

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directional

one extreme favored over the other

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Disruptive

both extremes favored at the same time

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Macroevolution

-evolution involving speciation and divergence of life into all its form

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speciation

2 different populations of a single species into separate species

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Biological species concept

a group of organisms capable of interbreeding and reproductively isolated from other organisms

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Prezygotic isolating mechanisms (premating)

-habitat isolation(species at same locale have diff habitats)
-temporal isolation(species reproduce at different seasons or different times of day)
-behavioral isolation (blue footed boobies)

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Mating prezygotic isolation (mating)

-mechanical isolation(genitals don't match)
-gamete isolation (sperm cannot reach or fertilize egg)

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postzygotic isolation (fertilization)

-zygote morality(fertilization occurs, but zygote doesn't live)
-hybrid sterility (mule)
-F2 fitness (redneck have kids w their cousins, more mutations bc less genetic variation)

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Allopatric speciation

geographical physical barrier

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sympatric

same region (replicate together over and over again, have multiple copies) ((polypolydy))

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Classification

-domain
-kingdom
-phylum
-class
-order
-family
-genus
-species
(dumb kids prefer chips over fancy green salads)

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Phylogeny

-grouped by shared homologous characteristics

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2 domain classification system

domain archaea
domain bacteria
domain eukarya

-something closely related may have the same characterstics

33

punctuated equilibrium

says that long periods of no visible change are followed by rapid periods of speciation
-when talking about the fossil record, speciation occurs relatively rapidly, and this can explain why few transitional links are found.

34

Balanced polymorphism

when natural selection favors the ratio of 2 or more phenotypes In generation after generation

-ex: heterozygous advantage; people who are heterozygous for the cystic fibrosis gene are more likely than others to survive a cholera epidemic. homozygotes are maintained in the human population