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18 Cards in this Set
- Front
- Back
Convergence
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adaptation of structures for similar functions
-e.g., various modified structures that enable vines to climb -example of homoplasy-structures with same function but different origin-occurs because different organisms are exposed to the same selective pressures like whale and fish body shape |
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Suboptimal design
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making something work from what is available rather than what is ideal
– trachea would be better behind esophagus because food must pass over the trachea to reach the esophagus -the human eye has a blind spot where the optical nerve attaches to the retina -human body structure, e.g. prone to back and joint problems, varicose veins and unprotected internal organs |
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Geographic distributions
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flightless bird (ostriches, emus, and rheas) are closely related and are similar morphologically, yet they are distributed in Africa, Australia and South America – they shared a common ancestor before the land masses separated
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Transitional or Intermediate forms
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show a combination of traits typical to ancestor and descendant populations
-in the fossil record, horses from 3-toed to 1, whales from land to sea, birds to dinosaurs (archaeopteryx), fish to amphibians (Tiktaalik roseae-which was found when scientists searched in fossils from the time frame when such an intermediate should have existed) -differences in DNA sequences range from almost none among very closely related species through increasing degrees of difference as we compare more remotely related taxa |
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phyletic evolution
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-linear progression of one species to another-used to think horse evolution was phyletic but is not, also used to think human evolution was phyletic but finding evidence that there were many groups of lineages with many ending-probably no organisms truly have phyletic evolution
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why is evolution the unifying concept in biology?
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-tries to explain origin in life forms
-integral to understand responses and adaptations of organisms -explains many of the findings in scientific research -universal-all organisms evolved -explains similarities among organisms-all life forms have dna, many have vestigial characters, why do we have differences -explains the why questions in biology |
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what is the definition of evolution?
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originally defined as descent with modification, or the change in populations over time, currently defined as changes in allele frequencies over time-have documented that allele frequents occur
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what are forces of evolution?
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selective pressure-artificial or natural, mutation, bottlenecks and genetic drift
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Natural selection
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individuals with favorable adaptations reproduce more successfully than those without adaptations
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Genetic drift
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random variation in the survival or reproduction of different variants
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evidence of reptilian ancestor of birds and mammals
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all mammals have left aortic arches, birds have right aortic arch, ancestral reptile had left and right arches
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process of protein development
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proteins made of chain of amino acids folded into complex 3 dimensional structure
amino acids made of nucleic acids coded from dna transcribed into rna then associated with ribosome which reads mrna 3 at a time trna brings nucleic acids to build the amino acid |
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evidence eyes have evolved
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amino acid sequence of development of eye is the same in humans, mouse, quail, zebrafish and only slightly different in fruit flies
all similar because they shared a common ancestor |
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Charles Darwin
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The Origin of Species (1859) 20+ years in the works, finally published because Wallace was about to publish same theory based on his work with birds in the Malayan archipelago
-both presented their ideas at same meeting and published at same time -descent with modification due to natural selection |
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dogs
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illustrate the power of artificial selection-many breeds have specific genetic problems due to inbreeding -artificial selection usually much stronger than natural selection
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evolution as a fact
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descent, with modification, from common ancestors
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evolution as a theory
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causes for descent with modification
-natural selection -genetic drift -mutation |
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Inheritance
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for evolution to function traits must be able to be passed from one generation to the next -no inheritance then every generation is a new start
-dna is the molecule of heredity |