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36 Cards in this Set
- Front
- Back
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What is evolution?
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Change in the genetic makeup of a population with time
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What is petrification?
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Process in which minerals replace the cells of an organism
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What are imprints?
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Impressions left by an organism
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What are molds?
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Form in hollow spaces of rocks, as the organisms within decays
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What are casts?
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Formed by minerals deposited in molds
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What is a trilobite?
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Primitive crustacean (relative of the lobster)
Dominant form of the early Paleozoic era |
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What are dinosaurs?
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Ancient animals similar to both reptiles and birds.
Dominant form of the Mesozoic era |
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What is in Eohippus?
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Primitive horse size of a fox, four toes, short teeth with pointed cusps for feeding on soft leaves
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What is an Archaepteryx?
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Missing link between reptiles (teeth and scales) and birds (has feathers)
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What are homologous structures?
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Same basic anatomical features and evolutionary origins
Wings of bat, flipper of whale, forelegs of horse, arms of man |
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What are analogous structures?
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Similar functions but different evolutionary origins and different patterns of development
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What does comparative embryology tell us?
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The earlier the state at which the development begins to diverge, the more dissimilar the adult organisms will be
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What does comparative biochemistry/physiology tell us?
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The more time that has elapsed since the divergence of two species, the more different their biochemical characteristics
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What are vestigial structures?
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Structures that appear to be useless but apparently had some ancestral function
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What is reproductive isolation?
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Interbreeding becomes impossible after a geographical barrier is put in place and then removed
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What is Lamarckian Evolution about?
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False theory
Use of an organ will lead to increase in size |
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Natural Selection in a Nutshell:
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Chance variations occur thanks to mutation and recombination
If the variation is "selected for" by the environment, that individual will be more "fit" and more likely to survive to reproductive age Survival of the fittest leads to an increase of those favorable genes in the gene pool |
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What is a population?
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All members of a particular species inhabiting a given location
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What is a gene pool?
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Within a population, the sum total of all the alleles for any given trait in the population
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What is the gene frequency?
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Decimel fraction for each allele represented in a population
p - dominant allele q - recessive allele p + q = 1 |
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What are the Hardy-Weinberg Principle conditions?
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1. The population is very large
2. No mutations that affect the gene pool 3. Mating is random 4. No net migration in/out of population 5. Genes in population are all equally successful at reproducing |
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What is the Hardy-Weinberg equation?
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p^2 + 2pq + q^2 = 1
p^2 = frequency of dominant homozygotes 2pq = frequency of heterozygous q^2 = frequency of recessive homozygotes |
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What does the Hardy-Weinberg equation not hold for extended populations?
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1. Natural selection
2. Mutation 3. Non-random mating 4. Genetic drift - refers to change in gene pool due to random chance 5. Gene flow - migration in/out of population |
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What is speciation?
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Evolution of new species
Environment forces the selection of specific genes Eventually, selection prevents interbreeding |
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What is a deme?
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Small local population
Ex: All bevers along specific portion of a river form a deme Members of deme resemble each other more than members of other demes |
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What is adaptive radiation?
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Emergence of a number of lineages from a single ancestral species
Difference between them is their niche Darwin's finches |
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What is phylogeny?
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Biologists seek to understand the evolutionary relationships between the species alive today.
The evolutionary history is termed phylogeny. |
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What is divergent evolution?
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Two species split from common ancestor
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What is parallel evolution?
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Two species develop the same characteristics independantly
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What is convergent evolution?
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Two different species of differing origins converge on a similar characteristic independantly
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What were the first life forms?
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Hetertrophs, depended on simple inorganic and organic compounds
Energy available in heat, electricity, solar radiation |
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What was Stanley L. Miller's experiment?
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Methane, hydrogen, ammonia, water, heat, UV circulated past electrodes
After 1 week, an abundance of organic materials including urea, hydrogen cyanide, acetic acid, and lactic acid had been synthesized |
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What were the original autotrophs?
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Contained primitive photosynthetic pathways
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What was the main impact of primitive autotrophs?
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Fixed CO2 during synthesis of carbohydrates and released oxygen as a waste product
Addition of molecular oxygen changed atmosphere from a reducing to an oxidizing one Some oxygen became ozone to help block high energy radiation from sun |
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What are the four general categories of living organisms?
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Autotrophic anaerobes - chemosynthetic bacteria
Autotrophic aerobes - green plants and photoplankton Heterotrophic anaerobes - yeasts Heterotrophic aerobes - amoebas, earthworms, humans |
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What is evolutionary fitness?
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Ability of an organism to contribute to the next genetic generation
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