Evolution Review Flashcards
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evolution
Genetic change in a population or species over generations; all the changes that transform life on Earth; the heritable changes that have produced Earth’s diversity of organisms.
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natural selection
differential success in reproduction by different phenotypes resulting from interactions with the enviornement. Evoltuion occurs when natural selection produces changes in the relative frequencies of alleles in a population’s gene pool.
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population
a group of interacting individuals belonging to one species and living in the same geographic area.
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Gene pool
all the genes in a population at any one generation
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Microevolution
a change in a population’s gene pool over a succession of generations; evolutionary changes in species over relatively brief periods of geologic time.
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macro-evolution
evolutionary change on a grand scale, encompassing the origin of new taxonomic groups, evolutionary trends, adaptive radiation, mass extinction
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adaptation
an inherited characteristics that enhances an organism’s ability to survive and reproduce in a particular enviornment
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Cladogram
an evolutionary tree that branches repeatedly, suggesting a classification of oranganisms based on time sequence in which evolutionary branches arise.
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variation
the evolution of new species
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Inference #1
Production of more individuals than the enviornment can support leads to a stuggle for existence among individuals of a population, with only a fraction of offspring survivng each generation
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inference #2
survival in the struggle for existence is not random, but depends in part on the hereditary make up of the surviving individuals. Those individuals whose inherited characteristics fit them best to their enviornment are likely to leave more offspring than less fit individuals. = Survival (and reprodctive success of the fittest)
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inference #3
this unequal ability of individuals to survive and reproduce will lead to a gradual change in a population, with favorable characteristics accumulating over the generations
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One method for variation to occur in population
crossing over
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2nd way for variation
random fertilization
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3rd way for variation to occur
varying assortment of chromosomes on equator in Meiosis I.
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4th way for variation
Random mutations
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what is the fossil record
fossils are preserved remnants left by organisms that lived in the past. they are found in sedimentary rocks.
the fossil record is the chronological evolution over millions of years of geological time engraved in the order in which fossils appear in rock strata.
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what do fossils show
they show the structures of animals in the past and how long ago they lived. their structure shows evidence of evolution that one animal evolved from another. they show us vestigial structures. changes over time and transitional forms (nostril movement). analogous structures.
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BiogeogrPHY
study of geographic distribution of species is called biogeography. first thing that helped darwin that organisms came from a common ancestor.
When Darwin went to galagapos islands, he saw that the animals resembled the animals on the mainland more than the nearby islands.
life placement on Earth. finding fossils on mountain tops, asteroids, meteors struck earh an one point in early stages to bring macromolecules.
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Comparative anatomy
the comparasion of body structures between different species is called comparative anatomy. same types of bones in the limbs of different maammals, they have varying funcions. They have one common ancestor, such similarity is called homology.
anatomy confirms that evolution is a remodeling process. Ancestral structures that orignally functioned in one capacity became modifies as they take on new functions.
whale at one point had legs. same bone arrangement in fish and hands. Whales swim up and down, and so do other land animals. the same thing in walking in lemurs and whales
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the tetrapod.
the tetrapod is a four legged creature that developed legs in the water and then came out of land. This contradicts the previous view that fish came out of the water.
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what is comparative embroyology
the comparasion of structures that appear druing the development of different organism before birth.
closely related organisms have similar stages in embryonic development. one sign is that verterbrates have common ancestor. at this stage, the animals look stringlingly similar. at some point, the common features develop into other structures.
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What is molecular biology
evolutionary relationships among species leave signs in DNA and proteins. we all have essentially the same genes with differences here and there. Darwin believed that all organisms came from a common ancestor.
Also the body segments are coded by the same gene in all animals.
Life starts with a macromolecule, cell, mulitcellular tissues, organs, complexity, same genes to make various parts of the body.
cambrain explosion: everyone from a common ancestor.
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what is gene flow
introduce new genes to a different enviornment, can increase variation.
introduction of new genes and exchange of new genes in new enviornment
