Evolution - ANSWERS1. theory that all organisms are related by common ancestry and due to descent with modification, changed over time
2. change in genotype/genetic make-up of a population from one generation to the next
What must happen for evolution to occur by natural selection - ANSWERS1. i...
what must happen for evolution to occur by natural
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Biology Evolution Exam 1Questions &
Answers
Evolution - ANSWERS1. theory that all organisms are related by common ancestry and
due to descent with modification, changed over time
2. change in genotype/genetic make-up of a population from one generation to the next
What must happen for evolution to occur by natural selection - ANSWERS1. individuals
must vary/be different
2. traits must be heritable
3. differential of survival: survival and reproductive success must vary and it's not by
chance
Adaptive Evolution - ANSWERSindividual with highest fitness will survive and
reproduce. ability to pass on genes to its offsprings
How do certain phenotypes become dominant over others in a population, leave
population, and emerge - ANSWERSnature favors traits that lead to high fitness,
becoming more common in a population: Adaptive evolution
-disadvantageous traits dont survive so cant pass on traits --> leaves population
-new traits arise because of mutations (mostly deleterious or neutral) but if good, then
remain in population
What leads to natural selection - ANSWERSDescent with modification:
Both parents pass down traits but the traits have slight modifications. because of this,
evolution changes a population over time: there are the phenotypes from the ancestors
and the new traits that have developed from advantageous mutations.
Evidence for evolution/descent with modification - ANSWERS1. Biogeography
2.Homology
3. Molecular Structure
4. Vestigial Traits
Biogeography - ANSWERSshows how organisms differ over geographic space
ex. Birds on Galapagos islands: all look physically similar, but vary somewhat to fit
niche. Shows that came from common ancestor but changed over time
Homology - ANSWERSsimilar structures or genes because of common ancestor but
acquired differences through evolution
ex. bats, humans, and dogs have same bone structure but used for diff. functions
ex. embryo of chicken, snake, human, and cat look alike during first stage
, Molecular Structure - ANSWERSall organisms have same genetic code (because of
common ancestor) with little difference.
-->differences exist due to mutations that are not deleterious and therefore still allow the
organism to function normally.
ex. DNA of mouse and human. Evolution proved because of some change in gene
sequence even though majority are parallel.
Vestigial Traits - ANSWERSphenotypes found in both modern organism and ancestor,
but serves no purpose for modern organism. Natural selection does not act to eliminate
it because not harmful to organism. Evidence for evolution because significant for
ancestor, but due to change over time, serves no function to us
ex. Humans have sequence for GLO pseudogene to synthesize vitamin C, but it does
not work.
Evidence for species changing over time - ANSWERS1.Fossils
2. Law of succession
3. Fossil series/transitional forms
4. Direct Observation
Fossils - ANSWERSfossils of extinct organisms look similar to modern day organisms
-----species are related but evolution occurs so that some traits are not shared with
modern organism
Law of succession - ANSWERSfossils in a particular area share similarities with
organisms in that area
Fossil series/Transitional forms - ANSWERSFossil records that show anatomical
changes in a specific organism
ex. whale: sea creature --> land animal --> sea creature. shows that species change
over time
Direct observation - ANSWERSObserving traits of organisms directly to note changes
ex. Drought in Galapagos islands left large seeds, so through evolutionary changes,
only birds with big and wide beaks had high fitness. Avg. beak size changed overall
James Ussher - ANSWERSgenesis occurred Sunday Oct 23rd 4004 B.C.; humans
have prehistory
Galileo, Copernicus, Newton - ANSWERSEarth is part of larger universe
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