Study Guide: Exam 1
55 Cards in this Set
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Fossils
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look at ancient organisms in life
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What is the most reliable proof of evolution?
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Fossils
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How is the age of fossils determined?
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by geology strata (layers) in the earth
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Relative Age
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Determined by strata
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Absolute Age
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Determined by Carbon Dating
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What does carbon dating compare?
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Radioactive C14 vs. normal C12
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14 C
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radioactive decays after death
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12 C
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normal carbon left over after death
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Half Life
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use half life of carbon to calculate the age of fossils
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Eras
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Consistent boundaries in strata
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Precambrian
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most of Earth's history Formation of Solar System Origin of life single cells start multicell
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Paleozoic Era
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Cambrian Carbinuferous Pangea
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Mesozoic
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Pangea broke up Reptiles flowering plants... meteor hit, large animals extinct
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Cenozoic Era
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Current continent position Age of mamals diversification Humans
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Oxygen
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At first a poison Organisms evolved to tolerate and require it
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Fact of evolution
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change in species over time
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Theory of Evolution
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Natural Selection change in species/ new species
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Darwin's Theory of Evolution (3)
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1) Populations change over time 2) Organisms multiply faster than their resources 3) Offspring tend to resemble parents
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Artificial Selection
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describes intentional breeding for certain traits, or combination of traits.
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Natural Selection
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The next generation resembles those who did best
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Fitness
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The likeliness that a organism has for reproduction
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Adaptation
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To become well suited A trait that is well suited
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Genotype
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set of all genes in one individual
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Phenotype
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Sets of traits in an individual
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Mutation
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gene that never existed before
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Components of Evolution
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Variation in population selection on variation inheritance of variation time
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Teleology
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The idea that natural processes have a goal or purpose
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Blending Inheritance
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offspring traits are the average of their parents variation would be lost
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Mendellian Genentics
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New combinations of genes produce new trait variation
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Population Genetics
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Alleles in a population
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Quantitative Genetics
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Phenotypes vary continuously
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Haploid
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One copy of each gene
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Diploid
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Two copies of each gene
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Polyploid
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Multiple copy
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Gene Pool
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Collection of all alleles in a population
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Stabilizing Selection
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average traits are the most successful
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Directional Selection
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Most successful on on extreme
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Disruptive Selection
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Extremes are most fit
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Genetic Drift
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chance differences in alleles Alleles are lost Reduces genetic variation Smaller population, more reduced
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Limitations of Natural Selection
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Trade Offs Small changes are viable What if no suitable varient exists?
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Allopatric Speciation
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requires genetic isolation geographic separation
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Sympatric Speciation
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Postzygotic reproductive variables (hybrids)
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Cladogenesis
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Creation of new clade
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Clade
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A group consisting of an ancestor
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Theory of Common Decent
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all species belong to a big family tree
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Phylogeny
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History of how species desended
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Phylogenetic Tree
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Graphical representation of phylogeny
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Ancestral Trait
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shared from inheritance
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Derived Trait
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Trait different from ancestor
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Homologous Trait
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shared by species descended from a common ancestor
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Convergent Evolution
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Independently evolved traits that look similar
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Parsimony
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Assume the least number of changes
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Cooperation
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An act or trait of one individual that benefits others
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Altruism
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Providing a benefit to another while adding cost to one's self
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Mutualism
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Cooperation between different species
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Study Guide: Exam 1