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20 Cards in this Set
- Front
- Back
natural selection
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population of organisms can change over the generations if individuals having certain heritable traits leave more offspring than other individuals
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evolutionary adaptation
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-result of natural selection
-a population's increase in the frequency of traits that are suited to the environment |
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evolution
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-genetic composition of the population has changed over time (descent with modification)
-genetic changes in populations over time |
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fossils
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imprints or remains of organisms that lived in the past
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Jean-Baptiste de Lamarck
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proposed that acquired characteristics are inherited
--proved wrong, but helped set stage for Darwin by proposing that species evolve as a result of interactions between organisms and their environments |
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Major points of darwin's theory
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1. organisms display variations
2. many are heritable variations 3. more offspring produced than survive to reproduce (struggle for existence) 4. Survivors have variations favored by the environment (adaptations) 5. Survivors will leave more offspring with those adaptations (natural selection) 6. Adaptations will accumulate over time (descent with modification) |
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fossil record
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ordered sequence of fossils as they appear in the rock layers, marking the passing of geologic time
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prokaryotes
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oldest known fossils from about 3.5 bya.
--ancestors of all life |
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eukaryotic organisms
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fossils in younger layers of rock
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general beliefs/views about natural world in 18th century
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1. a young earth
2. catastrophism 3. special creation 4. immutability of species |
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biogeography
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today's organisms evolved from ancestral forms
--closely related species found in some places (marsupials in australia) |
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comparative anatomy
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comparison of body structures between different species
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homologous structures
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common structures modified for different functions in different species
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homology
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anatomical similarity due to common ancestry
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transitional forms
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species with primitive traits indicating ancestry
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vestigial organs
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remnants of structures that served important functions in the organism's ancestors
--structures that are nonfunctional in some species but functional in others |
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comparative embryology
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comparison of anatomical structures that appear during the early stages of development of different organisms
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molecular biology
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provided strong evidence that all life forms are related through branching evolution from earliest organisms.
--all forms of life use DNA and RNA --genetic code (how RNA triplets are translated into amino acids) is universal |
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important point to darwin's theory
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evolution is the process
natural selection is the mechanism |
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modern synthetic theory
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1. integration of Darwin's theory with Mendelian genetics
2. natural selection is the primary mechanism of evolution 3. other mechanisms also cause evolutionary change: mutation, gene flow, genetic drift |