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DAT Biology > 8. Evolution + > Flashcards

8. Evolution + Flashcards

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1
Q

Evolution

A
  • chnages in pop, species, or group; changes in aallele (traits) frequencies in populations over time.
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2
Q

Microevolution

A
  • changes in allele frequencies within a population over time.
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3
Q

Macroevolution

A
  • patterns of changes in groups of related species over broad periods of time
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4
Q

Phylogeny

A
  • evolutionary relationships among species an groups of species.
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5
Q

Lamarck Theory

A
  • use and disuse: unused parts weakened, used parts get stronger. ex. giraffe neck
  • Inheritance of acquired characteristics: body features acquired during lifetime can be passed down to offspring (incorrect, only changes in genetic material is passed down).
  • natural transformation of species: organisms produced offspring w/ changes, transforming each later generation slightly more complex (no extinction or splits into more species) => incorrect
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6
Q

Natural Selection

A
  • survival of fittest (Darwinism) => now called neo-Darwinism (synthetic theory of evolution) or modern synthesis.
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7
Q

Evidence for Evolution

A
  1. Palentology: fossils
  2. Biogeography: unrelated species in different parts of the world look like when found in similar environments
  3. Embryology: similar stages of development among related species. Gill slits and tails are found in fish, chicken, pig, and human embryos
  4. Comparative Anatomy: describe two kind of structures that contribute to identification of evolutionary relationships.
    a. Homologous structure
    b. Analogous Structure
  5. Molecular biology: examine nucleotide and amino acid sequence of DNA and proteins from different species. more than 98% of nucleotide sequences in humans and chimpanzees are identical.
  6. Comparative Biochemistry: organisms w/ common ancestor = common biochemical pathway.
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8
Q

Ontogeny

A
  • similar stages of development.

- establish evolutionary relationships (phylogeny).

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9
Q

Homologous Structures

A
  • similar parts in different species as a result of a shared common ancestor.
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10
Q

Analogous Structures

A
  • similar parts in different species as a result of independent adaptation to similar environments.
  • No common ancestor
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11
Q

Natural Selection

A
  • responsible for producing adaptations that increase fitness (more offspring).
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12
Q

Darwin’s Theory Arguments

A
  1. pop possess enormous reproductive potential
  2. pop size remain stable
  3. resources are limited
  4. individuals compete for survival
  5. there is variation among individ in a pop
  6. much variation is heritable
  7. only most fit survive
  8. evolution occurs as favorable traits accumulate in the population
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13
Q

Stabilizing Selection

A
  • bell curve

- ex. avg height in humans is middle, favors intermediate

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14
Q

Directional Selection

A
  • favors traits that are at one extreme of a range of traits. traits at opposite extreme selected against.
  • ex. industrial melanism: selection of dark-colored (melanic) varieties in various species of moths as a result of industrial pollution.
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15
Q

Disruptive Selection

A
  • environment favors extreme or unusual traits while selecting against common traits. ex. short and tall are favored while avg is selected against.
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16
Q

Sexual Selection

A
  • differential mating of males (or females) in a population
  • female chooses superior males => incr fitness of offspring; they invest a lot of energy so they maximize quality.
  • males incr fitness by maximizing # of mates. They invest little energy so they max quantity.
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17
Q

Sexual Dimorphism

A
  • differences in appearance of males and females => a form of disruptive selection.
  • female choice leads to traits/behaviors in males that are favorable to female (colors, elaborate behavior) resulting in sexual dimorphism.
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18
Q

Sources of Variation

A
  1. mutation: new alleles introduced
  2. sexual reproduction : crossing over, independent assortment, random joining of gametes
  3. diploidy: presence of 2 copies of each chromosome. in heterozygous condition, recessive allele is stored for later generations => more variation maintained in gene pool.
  4. outbreeding: mating unrelated partners
  5. blanaced polymorphism: maintenance of diff phenotypes in a pop
    a. heterozygote advantage: heterozygous condition bears greater advantage than either homozygous conditions. ex. sickle cell heterozygotes (AS) have resis against malaria, and is common 14 % in Africa. heterozygotes (AS) are normal, homozygotes (SS) is fatal.
    b. Hybrid vigor (heterosis): superior quality of offspring resulting from crosses between two different inbred strains of plants. ex. hybrid corn from 2 inbred species is more resistant to disease.
    c. Frequency- dependent selection (minority advantage: least common phenotypes have a selective advantage. common phenotypes selected against (search image of common phenotype). Cycle: rare pheno increase, and is selected against, decre and becomes more advantag and increases again.
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19
Q

Neutral Variation

A
  • variation w/o selective value

- ex. fingerprints in humans

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20
Q

Geographic Variation

A
  • variation of a species dependent on climate or geographic conditions.
  • a graded variation of phenotype due to this is known as a cline: variation from North/South environ is a north-south cline.
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21
Q

Causes of Changes in Allele Frequencies

A
  1. natural selection
  2. gene flow - intro/removal of alleles due to emigration or immigration
  3. genetic drift - random incr/dec of allele by chance.
    a. founder effect
    b. bottlenck
  4. nonradom mating: indivd choose mates based on partic traits (ex. nearby). sexual selection: females choose superior traits. inbreeding: mate w// relatives.
  5. mutations
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22
Q

Hardy-Weinberg Equilibrium Conditions

A
  • allele freq remain constant from gen to gen
  • no mutations, all traits neutral (no natural selection), pop isolated (no gene flow), large pop (no genetic drift), random mating, no net migration.
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23
Q

Speciaton

A
  • formation of new species
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24
Q

Species

A
  • group of individuals capable of interbreeding
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25
Q

Allopatric Speciation

A
  • pop divided by geographic barrier => interbreeding prevented => gene freq diverge due to natu selection/mutation/genetic drift. if gene pool sufficiently diverged => will not interbreed when barrier is removed => new species formed
26
Q

Sympatric Speciation

A
  • formation of new species w/o presence of geographic barrier
  • balanced polymorphism: natu selection due to polymorphism. ex. diff colors of an insect pop provide camouflage to diff substrate, forming subpopulations that only interbreed among each other, diverging over time
  • polyploidy: more than normal 2 sets of chromosomes. nondisjunction results in diploid gametes that combine and form a tetraploid (4n) zygotes => reproduct isolated.
  • hybridization: two distinctly diff forms of a species (or two closely related species) mate and produce along a geographic boundary called hybrid zone
  • adaptive radiation: rapid evolution from single ancestor. occurs when ancestral species is intoduced to area with diverse geographic/ecological conditions. ex. galapagos finches
27
Q

Maintaining Reproductive Isolation

Prezygotic Isolating Mechanism

A
  • PREVENT FERTILIZATION
  • habitat isolation
  • temporal isolation: mate/flower in diff season/time
  • behavioral isolation: diff courtship ritual
  • mechanical isolation: genitalia not compatible
  • gametic isolation: male gametes don’t survive in environ of female gamete. gametes don’t recognize others.
28
Q

Maintaining Reproductive Isolation

Postzygotic Isolating Mechanism

A
  • hybrid inviability: zygote dies before repro maturity
  • hybrid sterility: hybrids become adults but can’t repro
  • hybrid breakdown: hybrid produces offspring that have reduced viability/fertility
29
Q

Divergent Evolution

A
  • two or more species that originate from common ancestor and become increasingly diff over time (speciation)
30
Q

Convergent Evolution

A
  • two unrelated species share similar traits due to similar environments (analogous traits)
31
Q

Parallel Evolution

A
  • two related species made similar evo changes after divergence from common ancestor
32
Q

Coevolution

A
  • evo of one species in response to evo in another (predator/prey)
33
Q

Macroevolution

Phyletic Gradualism

A
  • evo occurs by gradual accumulation of small changes
  • unlikely to be valid bec intermediate stages of evo are missing (fossils)
  • fossils only reveal major changes in groups of organisms
34
Q

Macroevolution

Punctuated Equilibrium

A
  • evo history consists of geologically long periods of stasis (stability) w/ little/no evo followd by short period of rapid evo.
  • absence of fossils of intermediate stages of evo is considered data that confirms rapid evo events.
35
Q

Origin of Life

A
  • Universe: 12-15 billion years old
  • solar system: 4.6 billion years old
  • Earth: 4.5 billion years old
  • Prokaryote Fossils: 3.6 billion years old
  • Photosynthetic bacteria: 2.3 billion
  • Eukaryotes: 1.5 billion
36
Q

Steps that Led to First Primitive Cell

A
  1. Earth and atmosphere form (volcanoes): CH4, NH3, CO, CO2, H2, N2, H2O, S, HCl, HCN, little/no O2
  2. Primordial seas formation: earth cools => gases condense => sea w/ water and mineral
  3. Complex molec synthesized: organic soup from inorganic, energy from UV, lighting, heat, radiation => acetic acid, formaldehyde, and amino acids
  4. Polymers and Self-replication: monomer => polymer (dehydration condensation). Proteinoids are abiotically produced polypeptides
  5. Organic molec conc/isolated into protobionts
  6. primitive heterotrophic prokaryotes
  7. primitive autotrophic prokaryotes: mutation, heterotroph gained ability to produce its own food => cyanobacteria
  8. O2 and ozone layer + abiotic chemical evo ended: O2 from photosynthesis + UV => ozone =: no energy for abiotic synthesis => term of primitive cells
  9. Eukaryotes formed: endosymbiotic theory => euk cells originated mutually among prok (mitochondria, chloroplast establish resident inside another prokaryote
37
Q

Oparin & Haldane Organic Soup Theory

A
  • if there were O2 in early earth, no organ molec would have formed
  • hypothesis: origin earth enviorn was reducing providing chemical requir to produce complex molec from simpler ones. In an oxidizing environ, you’d break complex molec apart.
38
Q

Stanley Miller

A
  • tested theory of Oparin Haldane and produced organic molecules
  • Miller and Urey used ammonia, methane, water, and hydrogen sealed + simulated lightning => several organic molec, AA’s, starting material, nut no nucleic acids.
39
Q

Proteinoids

A
  • abiotically produced polypeptides

- amino acids dehydration on hot, dry substances confirm this.

40
Q

Protobionts

A
  • precursor of cells, like cells metabolically active but unable to reproduce
  • microspheres/liposomes and coacervates are experimentally (abiotcally) produced protobionts that have some selective permeable qualities.
41
Q

Evidence for Endosymbiotic Theory

A
  • thylakoid membrane of chloroplasts resemble photosynthetic membrane of cyanobacteria
  • mitochondria and chloroplasts have their own circ DNA not wrappd w/ histones (prok like)
  • ribosomes of chloroplasts/mitochondria resemble those of bacteria
  • reproduce independently via process similar to binary fission, two membranes.
42
Q

Modern Atmosphere Composition

A
  • 78% N2
  • 21% O2
  • 1% Ar
  • a lot of other less important gases
43
Q

Vestigial Structures

A
  • appear useless but had ancestral functions

- ex. humans (appendix and tail)

44
Q

Mullerian Mimicry

A
  • two or more harmful species
  • not closely related
  • share one or more common predators
  • mimic each other’s warning signals
45
Q

Batesian Mimicry

A
  • deceptive harmless species evolved to mimic warning signals of a harmful species directed at common predator
  • Bait
  • Poser
  • Impostor
46
Q

Parapatric Speciation

A
  • continuous population but doesn’t mate randomly. individuals more likely to mate w/ geo neighbors, divergence may happen due to reduced gene flow
47
Q

Peripatric Speciation

A
  • similar to allopatric speciation in that a pop is isolated and prevented from exchanging genes, but one pop is much smaller so subject to faster genetic drift
48
Q

Anagesis/phyletic evolution

A
  • one species replaces another, straight path evo
49
Q

Cladogenesis/branching evolution

A
  • new species branch out from parent species
50
Q

Clade

A
  • a group of species that include a common ancestor and all of its descendents (aka monophylum)
51
Q

Sere

A
  • a particular stage of an ecosystem
52
Q

Mold

A
  • an organic matter leaves an impression in rock or inorganic matter, later the organic matter decays and leaves a negative impression
53
Q

Cast

A
  • type of fossil formed when a mold is filled in
54
Q

Deme

A
  • small local population

- ex. all beavers along specific portion of a river

55
Q

Autotrophic Anaerobes

A
  • chemosynthetic bacteria
56
Q

Autotrophic Aerobes

A
  • green plants, photoplankton
57
Q

Heterotrophic Anaerobes

A
  • yeast
58
Q

Heterotrophic Aerobes

A
  • amobas, earthworm, humans
59
Q

Synapomorphies

A
  • shared traits derived from an evo ancestor common to all members of a group
60
Q

Law of Parsimony

A
  • simplest explanation is most likely correct (phylogenetic trees: fewest number of chnages w/ respect to synapomorphies)

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