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Biology > Chapter Four: Evolution > Flashcards

Chapter Four: Evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Evolution

A

The gradual development of organisms over time.

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2
Q

Common Descent (3)

A
  1. All organisms are composed of cells
  2. All take in chemicals and energy from the environment
  3. All reproduce, respond to stimuli, and evolve
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3
Q

Fossil

A

The preservation of the general shape of an organism. Formed when minerals in the earth harden over it’s body upon its death

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4
Q

Transition Fossil

A

A fossil representing an evolutionary link in the fossil record, indicating a common ancestor

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5
Q

Strata

A

Layers of the earth representing geological periods of time.

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6
Q

Relative Dating

A
  • Fossil dating method using layers of strata to determine which era it came from. The lower the strata, the older the fossil
  • Only accurate if the strata has not been twisted or upturned from natural processes
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7
Q

Radiometric/Absolute Dating

A

Dating method which uses the half-lives of isotopes present in the fossil to determine its age. In organic fossils, carbon is typically used.

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8
Q

Mass Extinction

A

Event that extinguishes a large number of organisms in a short period of time. This causes only the most well-adapted organisms to survive.

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9
Q

What is an example of a mass extinction?

A

The Cretaceous period; a large number of meteorites hit the earth and the debris blocked the sunlight. Many plants and animals died.

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10
Q

Biogeographical Evidence for Evolution

A
  • Study of the distribution of plants and animals
  • continental drift shown through distribution of similar fossils on different continents: evolving species unable to migrate
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11
Q

Homologous Structure ( + example)

A

Has same function and basic structure, indicates a common ancestor
ex) A human arm and a whale forelimb

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12
Q

Analogous Structure ( + example)

A

Same basic function but different origin

ex) bird’s wing and bee wing

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13
Q

Vestigial Structure ( + example)

A

Anatomical structure fully functional in one group and reduced or nonfunctional in another
ex) Human coccyx (tailbone)

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14
Q

Biochemical Evidence for Evolution

A
  • All organisms have the same three basic biochemical molecules: DNA, ATP, and general enzymes
  • The degree of similarity between DNA base sequences and amino acid sequences indicate the degree of relatedness
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15
Q

Evolution of micromolecules

A

Earth’s early atmosphere according to Miller was full of methane, hydrogen, and ammonia
-when applied with enough each (ex lightning) these molecules could form organic compounds and amino acids

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16
Q

Miller Experiment

A

Simulated conditions of early earth (methane, hydrogen, and ammonia) and applied an electric spark. Yielded amino acids without the use of oxygen.

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17
Q

Macromolecules: RNA first hypothesis

A

RNA functioned both as an enzyme and a substrate. Some viruses use RNA as their genetic material

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18
Q

Macromolecules: Protein first hypothesis

A

Sidney Fox’s experiments

  • amino acids can form polypeptides when exposed to dry heat
  • amino acids collected in puddles and formed proteinoids within microspheres
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19
Q

Microsphere

A

A chemical reaction separated from its environment

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20
Q

Macromolecules: Cairnes-Smith hypothesis

A
  • Proteins and RNA at the same time: Clay attracted small organic molecules, which served as inorganic catalysts for polypeptide formation
  • Fueled by energy from radioactive decay
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21
Q

The Protocell

A
  • Proposed structure of a protein-lipid membrane which carried on an energy metabolism
  • Microspheres were exposed to lipids, created a coacervate with a protein-lipid membrane
  • the phospholipid automatically formed a liposome
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22
Q

Coacervate

A

Microscopic spontaneously formed spherical collection of lipid molecules, held together by electrostatic forces

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23
Q

Liposome

A

A spherical structure with at least one lipid bilayer

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24
Q

The Heterotroph Hypothesis

A
  • Since nutrition was plentiful in the ocean, the first organism was probably a heterotroph
  • used ATP first; was a fermentative process
  • Had a catalytic ability like microspheres and took in available enzymes (beginning of glycolysis)
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25
Q

The True Cell (RNA first hypothesis)

A

-First true cell had RNA genes; reverse transcriptase produced DNA from RNA

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26
Q

Reverse Transcriptase

A

An enzyme that generates complimentary DNA from an RNA template. Requires DNA polymerase and a nucleus

27
Q

The True Cell (Protein-first hypothesis)

A

Complex enzymatic processes may have been necessary for the formation of DNA and RNA - requires proteins

28
Q

The True Cell (Cairnes-Smith hypothesis)

A

RNA genes could replicate because proteins present for catalysm. Once protocells could replicate, they became true cells

29
Q

Order of the Evolution of the Cell (5)

A
  1. Micromolecules
  2. Macromolecules
  3. The Protocell
  4. The Heterotroph
  5. The True Cell
30
Q

Microevolution

A

A change in the gene frequency of a population

31
Q

Population

A

All members of a species occupying a particular area

32
Q

Hardy-Weinberg Law

A

Equilibrium of allele frequencies in a gene pool will remain constant in each generation of a large sexually reproducing population, as long as certain conditions are met.

33
Q

Hardy-Weinberg Equation

A

p2 + 2pq + q2

34
Q

Agent of Evolutionary Change: Mutations

A

Only source of new alleles in a population; can also be an adaptive variation.

35
Q

Gene Pool

A

the sum total of all alleles in a population

36
Q

Agent of Evolutionary Change: Genetic Drift

A

Change in allele frequency due to chance

37
Q

Founder Effect

A

A few individuals found a colony and their collective genes represent a small fraction of the original gene pool

38
Q

Bottleneck Effect

A

Population is subjected to near extinction by a disaster and only a few genotypes contribute to the next generation

39
Q

Agent of Evolutionary Change: Gene Flow

A

Movement of alleles between populations, keeps the gene pools of two or more populations similar

40
Q

Agent of Evolutionary Change: Nonrandom Mating

A

Individuals pair up according to genotype and phenotype. Increases frequency of recessive abnormalities (ex. inbreeding)

41
Q

Agent of Evolutionary Change: Natural Selection

A

Process by which populations adapt to their environment.

42
Q

Requirements for Natural Selection (4)

A
  1. Variation
  2. Inheritance
  3. Differential Adaptiveness (some differences have a survival benefit)
  4. Differential Reproduction (better adapted individuals survive to reproduce more offspring)
43
Q

Fitness

A

Measured by the number of fertile offspring produced by an individual. Variations occur from mutations, crossing over, and independent assortment.

44
Q

Stabilizing Selection

A

An intermediate, or average, phenotype is favoured. Improves adaption of a population to a stable environment.

45
Q

Directional Selection

A

An extreme phenotype is favoured. Distribution curve shifts in that direction.

46
Q

Species

A

A group of interbreeding sub populations that share a gene pool

47
Q

Premating Isolation Mechanisms (4)

A

Reproduction never attempted

  1. Habitat Isolation
  2. Temporal Isolation
  3. Behavioral Isolation
  4. Mechanical Isolation
48
Q

Premating Isolation Mechanism: Habitat Isolation

A

Species at same locale occupy different habitats

49
Q

Premating Isolation Mechanism: Temporal Isolation

A

Species reproduce at different seasons or different times of day

50
Q

Premating Isolation Mechanism: Behavioral Isolation

A

Courtship behaviour differs; species respond to different songs, calls, pheromones, or other signals

51
Q

Premating Isolation Mechanism: Mechanical Isolation

A

Genitalia unsuitable for one another

52
Q

Postmating Isolation Mechanisms (4)

A

Reproduction may take place but it does not produce fertile offspring

  1. Gamete Isolation
  2. Zygote Mortality
  3. Hybrid Sterility
  4. F2 Fitness
53
Q

Postmating Isolation Mechanism: Gamete Isolation

A

Sperm cannot reach or fertilize egg

54
Q

Postmating Isolation Mechanism: Zygote Mortality

A

Fertilization occurs, but zygote dies

55
Q

Postmating Isolation Mechanism: Hybrid Sterility

A

Hybrid survives but is sterile and cannot reproduce

56
Q

Postmating Isolation Mechanism: F2 Fitness

A

Hybrid is fertile, but F2 has reduced fitness

57
Q

Allopatric Speciation

A

Geographical barriers separate a population into two groups

58
Q

Sympatric Speciation

A

Separation occurs without any geographical barriers. Two subgroups of a population becomes reproductively isolated.

59
Q

Phyletic Gradualism

A

Change of species is slow but steady after a divergence

60
Q

Punctuated Equilibrium

A

Stasis is punctuated by speciation, occurs too rapidly to fossilize

61
Q

Cladogram

A

A branching, tree-like diagram with successive points of divergence from a common ancestor

62
Q

Cladistic

A

A branch of a cladogram

63
Q

Clad

A

The specific trait of analyzed in a cladogram

Biology (8 decks)

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