Unit 3 BSC2011 Exam 3 Study Guide 2012 Concepts L19 Read Section 22 2 Evolution Intro Evo Natural Selection Understand the difference between natural selection and evolution Evolution stands for the gradual change in time The actual process of change in allele frequencies Individuals don t evolve populations do Natural selection is an explanation as to how evolution happens where some individuals w certain traits survive and reproduce cuz of those traits Understand the basic principle of natural selection Def process of which individuals w certain inherited traits tend to survive and reproduce higher rates because of those traits If an environment change those with the necessary traits suit better in the new environment survive and reproduce higher rates Those alleles get passed on more than the ones with the least advantageous traits Once environment changes again the preferable trait does as well It explains adaptations of organisms and the unity and diversity of life Natural selection is always operating but favorable traits are determined by the species environment Be able to distinguish between evolutionary change and other kinds of changes Evolutionary changes include natural selection artificial selection and adaptation Understand that evolution produces allele frequency changes inherited phenotypic changes differences among populations new phenotypes and new species All these things are needed in order for evolution to happen Evolution by natural selection can t happen if all the individuals in a population are genetically identical 4 the heritable trait L20 Read all of Ch 22 Evo Intro Darwin Know that Darwin came up with his ideas after voyage on the Beagle Galapagos animals were influential Galapagos group of volcanic islands west of South Ameri Discovered the finches Some unique to to individual islands not known from anywhere else in the world others found on same 2 adjacent islands Darwin hypothesized that Galapagos colonized by strayed organisms from S Ameri and then diversified giving rise to new species on the various islands Know that Wallace independently came up with same idea Wallace British naturalist working in S Pacific islands who developed a natural selection hypothesis similar 2 Darwin s Asked Darwin 2 evaluate his works forwarded it 2 Lyell Wallace submitted his ideas 4 publication 1st but credited Darwin since his works were developed so extensively Understand the five ideas in Darwin s theory 1 Evolution has happened 2 All life has a common ancestor 3 The diversity of life is the result of a series of splits in the lineage family tree of living things 4 Natural selection is the primary mechanism driving evolutionary change 5 Evolution occurs gradually over time Understand that exposure to the diversity of life around the world was an important influence Traveling to different parts of the world helped both biologist to compare new species and develop their ideas about evolution Understand the basic process of natural selection Understand that evolution can be depicted as a branching tree What Darwin viewed the history of life as Multiple branching tree from a common trunk ancestor out to tips of the youngest twigs Descent of Modification explains the unity of life diversity of life and the match between organisms their environments Organisms share many characteristics unity As descendent lived in various habitats over millions of years they got diverse modifications adaptations that adjusted them to specific ways of life Led to rich diversity of life today Ex three living species of elephant L21 Read 22 2 22 3 Evidence of Evolution and Modern Evolutionary Biology Know the different types of evidence for evolution and understand their significance Life on Islands Similar to mainland but unique endemic Inferred that individuals arrived on the islands followed by evolution of new forms Fossil Record Nonrandom change in form over time Shows that past organisms differed from present day ones and that many species have become extinct Observation of Natural Selection Artificial Selection Humans modifying other species over generations by selecting breeding individuals w desired traits This was a familiar example since done with plants and animals that helped convince even the most skeptical readers Comparative Anatomy Homology different species have same structures modified in different ways Pic homologous structures Comparing early stages of development in different animal species reveals additional anatomical homologies not visible in adult organisms Vestigial structures remnants of features that served a function in the organism s ancestors but aren t of any use in current organism Convergent Forms Distantly related organisms can resemble one another because of convergent evolution the independent evolution of similar features in different lineages Ex marsupial sugar glider Eutherian flying squirrel Since these 2 mammals are from different ancestors and have adapted to similar environments in similar ways it helps the understanding of evolution These species share common features cuz of convergent evolution but aren t from common ancestry analogous features NOT HOMOLOGOUS Ontogeny Phylogeny organisms can be mapped into a phylogeny through homology pg 464 Molecular Evolution Random changes in non coding DNA reflects ancestry Gene Homology similarities among organisms at the molecular level Likely all species descended from a common ancestor that used DNA and RNA Some homologous genes acquire new functions or lost them while others have retained their original function Development and Evolution detailed understanding on how differences in genes can lead to different developmental pathways L22 Read 23 1 23 2 23 3 23 4 pgs 479 481 Evolution Genetics Understand that evolutionary change means genetic change Genetic variation differences among individuals in terms of their genes DNA segments makes evolution possible 23 2 Understand that populations can be described in terms of allele frequencies and that evolutionary forces can change frequencies A populations genetic makeup can b characterized by its gene pool has all copies of every type of allele at every locus in all member of the population Each allele has a frequency proportion in the population 23 2 Understand that Mendelian inheritance will not change allele frequencies Some phenotypic variation isn t inheritable Phenotype is a product of an inherited genotype many environmental influences 23 2
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