Exam 1 Flashcards
58 Cards in this Set
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Ariostotle
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scala nature, said it is like a ladder of life, every rung is "fixed" each step has one species that cannot move up or down
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Linneaus
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father of taxonomy, binomial nomeclatue, allows us to classify organisms based on morphology
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Curvier
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catastrophism, father of paleontology
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catastrophism
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when one species went extinct a new species migrated into the area
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Hutton
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gradualism
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Gradualism
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slow processes create big change overtime
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Lyell
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Uniformitarism
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Uniformitarnism
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Geologic processes occur at the same rage overtime
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Lammarck
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adaptation, use and disuse, inheritance of acquired characteristics
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Darwin
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Theory of evolution, natural selection, influenced by Lyell and Hutton
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Natural Selection
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the mechanism behind evolution, Requires heritable variation, differential reproductive success, selective mating, does not create favorable traits
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Phenotype
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the smallest unit that natural selection can act on
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Intrasexual selection
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direct competition for members of the same sex, for mates.
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Intersexual selection
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mate choice, chosen based on desirable characteristics
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Sexual Dimorphisms
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differences in males and females, EX: size, plumage, manes, antlers
the result of intersexual selection
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Stabilizing selection
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favors the average
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Disruptive/diversifying Selection
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favors both extremes
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Directional selection
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favors one extreme
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Homology
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similarities based on common ancestry
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Anatomical Homologies
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similar physical structures EX: forelimbs of mammals have the same skeletal elements
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Embryological Homologies
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Homologies present during embryological development EX: pharyngeal pouches, gills in fish, Eustachian tubes in humans
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Molecular Homologies
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More closely related organisms have more similar DNA
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Covergent Evolution
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Two different lineages forming similar structures EX: Bird and Bat, Porcupine and Cactus
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Biography
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Geographic Distribution of species
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Population Genetics
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study of genetic variation within populations
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Population
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a group of individuals within the same species
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Species
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a group of populations that can interbreed and produce fertile offspring
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Allele
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a specific form of a gene
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Fixed allele
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an allele that has a frequency of 1
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Hardy-Weinberg Theorem
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non-evolving population, allele frequencies and genotype frequencies can NOT change overtime
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Microevolution
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changes in the genetic structure of populations overtime
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H-W Assumptions
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Large Population
No net migration
No net mutation
Random mating
No natural selection
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Gene Flow
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migration of alleles, into or out of the population
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Allopatric speciation
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With geographic separation
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Mutation
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original source of variation, the only way to create new alleles
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Genetic Drift
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Acts on small populations, Defined as chance genetic change
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Bottleneck effect
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a disaster reduces the population, genetic diversity is decreased, nothing is selected for pure chance of survival
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Founder Effect
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a group of individuals of a population, by chance migrate and diversify, genetic variation is decreased
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Sexual Recombination
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does not create new alleles, shuffles existing alleles, occurs during meiosis
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diploidy
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two alleles for each gene
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Balanced Polymorphisms
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maintains stable frequencies of 2 or more phenotypes in a population
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Heterozygote advantage
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heterozygotes are favored over the 2 homozygotes
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Frequency dependent selection
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if one allele becomes too common then its survival and reproduction will decrease
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Cline
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variation in a trait across a geographical axis
ex: tree height decreasing with increasing altitude
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Macroevolution
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speciation, formation of new speices
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Anagenesis
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one entire species evolves into a new species, does not increase genetic diversity
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Cladogenesis
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part of a species evolve into a new species, increases genetic diversity
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Biological Species Concept
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a population or group of populations that can interbreed and produce fertile offspring, but cannot produce offspring with other species
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Ecological Species Concept
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defines organisms based on their niche
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Morphological Species Concept
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characterizes species based on their structural features
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Prezygotic Barreiers
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barriers that occur before the zygote is formed/fertilization
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Archean Eon
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involves the origin of earth, first prokaryotic cells appeared and preformed photosynthesis, triggered the oxygen revolution
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Proterozoic Eon
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first eukaryotic cells appeared, first multicellular life (algae), first animal life
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Phanerozoic Eon
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has life as we know it
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Paleozoic Era
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535 mya, oldest era, the age of fishes, plants fungi and arthropods invade land, first land vertebrates (amphibians), first vertebrates with celled eggs amniotes
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Mesozoic Era
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age of dinosaurs, cone-bearing seed plants dominate, first mammals appear
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Cenozoic Era
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diversification of mammals flowering plants birds and insects first humans appear
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why natural selection cannot produce perfect organisms:
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1. selection can only edit existing variations
(favors the fittest phenotypes, new advantageous alleles don't arise on demand)
2. evolution is limited by historical constraints
(each species has a legacy of decent with modification from ancestral forms)
3. adaptations are often compro…
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