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84 Cards in this Set
- Front
- Back
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evidence of evolution
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-geological timescale
-fossil record -biogeography -anatomical relationships -embryonic development -molecular relationships |
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barringer meteor crater is in
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arizona
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radiometric dating of medeorite fragments date back
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4.5 billiion years ago
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clues to evolution lie in
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earth, body structure, and molecules
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life on earth arose
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3.8 billion years ago
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the variety of organisms we see today are a result of
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changes in body structures and molecules that have slowly accumulated over time
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geological timescale
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what scientists use to divide the history of the earth into eons and eras
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_____ is what scientists use to divide the history of the earth into eons and eras
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geological timescale
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the periods in geological timescales are defined by
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major geological or biological events like mass extinctions
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paleontology is the study of
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fossil remains or other clues to past life
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this is the study of fossil remains or other clues to past life
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paleontology
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_____ provide the origional evidence for evolution
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fossils
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evidence for evolution indicates
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all organisms derived from a common ancestor
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fossil records are not complete because
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there are no fossils in between transititional forms between groups.
-because some organisms fail to fossilize, erosion, and movement of earths plates |
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some organisms fail to fossilize
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those with soft bodies
ex jellyfish |
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reasons fossils fail to fossilize and the fossil record is incomplete is because
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some organisms fail to fossilize, erosion, and movement of earths plates
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marine fossils from oklahoma show an ocean once covered
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central us oklahoma area
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dating fossils yields clues about
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the timeline of lifes history
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the simpler and less precise method of dating fossils is
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relative dating
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_____ assumes that lower rock layers have older fossils than newer layers
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relative dating
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relative dating
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the simpler less precised method of dating fossils which assumes older rock contains older fossils
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absolute dating
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uses chemistry to determine how long ago a fossil formed
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_____ uses chemistry to determine how long ago a fossil formed
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absolute dating
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radiometric dating
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a type of absolute dating that uses radioactive isotopes
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a type of absolute dating that uses radioactive isotopes
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radiometric dating
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throughout life organisms accumulate
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c14 - a radioactive isotope
and c12 - stable element |
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the two carbons accumulated throughout life
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c14(isotope) and c12
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while alive
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replacement of c14 and c12 equals decay
-stabile levels |
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after death
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c14 half life is 5730 years
-c14 slowly declines which indicates how old a fossil is |
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______ have a constant amount of carbon 14 and carbon 12 in their tissues and bones because they are constantly adding carbon 14 and 12 to their bodies
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living organisms
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carbon 14 leaves as
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nitrogen 14 in living organisms
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after death carbon14 leaves as
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nitrogen 14
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after the organism dies
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no more carbon 12 or 14 is added
-carbon 14 decays at a constant rate, leaving the organism as nitrogen |
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half life of carbon 14 is
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5730 years
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how does radiometric/ absolute dating work
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by determining the amount of c14 in a fossil, scientists can estimate when an organims lived
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fossils with the most carbon 14 are
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newer fossils
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fossils with the least carbon 14 are
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older fossils
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_____ considers species geographical locations
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biogeography
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earths geography has changed drastically over the last
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200 million years
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pangaea
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all continents joined together to form one supercontinent
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the two major continents
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laurasia and gondwana (together are pangaea)
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theory of plate tectonics
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-earth consists of several rigid layers (tectonic plates) that move in response to forces acting deep within the planet
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earth consists of several rigid layers that move in response to forces acting deep within the planet
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plate tectonics
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continents move because
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plate tectonics
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earthquakes and volcanos are evidence of
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plate tectonics
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fossils help piece together
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earths continents into pangaea
-certain species live on multiple continents which would only be explained that they once shared a land |
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wallaces line
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indian ocean
-animals on either side of wallaces line evolve independently |
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biogeographical studies shed light on
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evolutionary events
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how have the positions of earths continents changed over hte past 200 million years
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the continents have drifted apart from the supercontinent, pangaea, into todays 7 continents through plate tectonics movement of the earth
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_______ reveal common descent
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anatomical relationships
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investigators often look at ______ to determine the evolutionary relationship between two organisms
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anatomical relationships
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two structures are homologous if
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similiarities between them reflect common ancestry
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bone configuration being similar represents
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homologous structures
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______ need not have the same function or look exactly alike
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homologous structures
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different selective pressures in each animals evolutionary line have led to
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small changes from their ancestors bone structure
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vestigial structure
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structure that has lost its function but is homologous to a functional structure in another species
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structure that has lost its function but is homologous to a functional structure in another species
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vestigial structure
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vestigial hind limbs in snakes and whales represent
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common ancestry between certain organisms
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humans vestigial structures
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goose bumps= muscles that pull up hair follicles to keep us warm in the past
tail= during embryonic development but is lost wisdom teeth appendix |
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anatomical structures are analogous if
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they are superficially similar but did not derive from common ancestor
-products of same environment not same ancestor ex. cave animals |
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convergent evolution
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produces similar structures in organisms that dont share the same lineage
- independent |
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produces similar structures in organisms that dont share the same lineage
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convergent evolution
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convergent evolution is
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analogous structures
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_______ provide evolutionary clues
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embryonic development patterns
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anatomical evidence is often most obvious in
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embryos
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homeotic genes
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control an organisms development
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similar embryos develop into different organisms because
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homeotic genes
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small differences in gene development
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make the difference between a limbed or non limbed organism
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where homeotic genes overlap
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neither of the genes are present
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______ control an organisms development
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homeotic genes
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homeotic genes help explain how
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a few key mutations might produce new species
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comparing _____ and __________ determines evolutionary relationships in unprecedented detail
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DNA and protein sequences
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more likely that similarities in dna and protein sequences are due to
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common ancestry and that differences arose by mutation after the species diverged from the ancestral type
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cytochrome c
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a mitochondrial protein that is often used in molecular comparison
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the number of amino acid cytochrome c differences indicate how
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closly related two organisms are (the smaller the number the more related)
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the more amino acid differences the
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more distant the common ancestor
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______ put dates to evolutionary events
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molecular clocks
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genetic differences over time (mutations) are shown through
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molecular clocks
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when more than one species when considering how many differences
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count for both
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1 mutation every 10 million years. 6 nucleotide difference between 2 species. how long ago did these organisms split from a common ancestor
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30 million years ago
- 3 changes per species = 6 nucleotide differences |
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the fact that all our dna is similar shows common ancestry and our protein sequences differences show time of seperation from ancestory
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how dna and protein sequences show evolution
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evolution does not always
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lead to greater complexity
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evolution can lose traits
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yea
ex. cave salamander and snakes |
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evolution favors certain traits better for the enviornment which then
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can lead to losing traits to be more suited for the enviornment thus evolving backwards
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