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Ch. 6 Evolution & Ecology Key Concepts Concept 6 1. Evolution can be viewed as genetic change over time or as a...

Ch. 6 Evolution & Ecology Key Concepts Concept 6 1. Evolution can be viewed as genetic change over time or as a process of descent w/ modification. Concept 6 2. Natural selection , genetic drift & gene flow , can cause allele frequencies in a population to change over time. Concept 6 3. Natural Selection is the mechanism for adaptive evolution. Concept 6 4. long-term patterns of evolution are shaped by large-scale processes such as speciation mass extinction , , &adaptive radiation. Concept 6 5 Ecological. interations & evolution exert a profound influence on one another.  rophy Hunting & Inadvertent Evolution : A Case Study What are Bighorn sheep noted The male's large curl of horns. for ? why has Bighorn Sheep Human action such as habitat encroachment , hunting , & population I by 90 % in introduction of domesticated cattle the past 200 years ? What was the result of the Hunting of bighorn sheep has been restricted throughout North 90 % b in the Bighorn Sheep America population ? True or False Scientist. are True concerned that trophy hunting is having negative effects on today's small populations of bighorn sheep. What does trophy huntingThe strongest & largest males. remove ? What happens when the leads to a reduction in age & Size at which the organisms largest & Older organisms are sexually mature. being targeted ?  What is Evolution ? Concept 6 1. Evolution can be viewed as genetic change over time or as a process of descent w/ modification. Learning objectives 6 1 1 Summarize the.. genetic basis Biologists often define evolution in a relatively narrow for the evolution of traits in sense as change over time in the frequencies of alleles in a organisms. population..1 2 6. Explain how evolution can be· Evolution can also be viewed as descent u/ modification , a process in considered the accumulation of trait which populations accumulate differences over time & hence differ from differences between populations. their ancestors · Natural Selection modifies populations by favoring individuals w/ so me heritable traits over other individuals. · Althouch natural selection acts on individuals , an individual does not evolve-either it has a favored trait or it does not. Only populations evolve. What are I ways to look at 1 genetic changes evolution ? 2) how organisms accumulate differences from their ancestors What is another way to talk allele frequency change about genetic change ? What is it called when descent w/ Modification organisms accumulate differences from their ancestors ?  Evolution is allele frequency change Horn size is an trait inherited What is an inherited trait ? An organism w/ a certain trait tend to have offspring with that certain trait · Because trophy hunting eliminates w/ small horns selectively rams. large horns , what is the outcome ? What are the basic principles of Genes are composed of DNA & , they specify how to build (encode genetics ? proteins. · A given gene can have two or more forms (known as alleles that result in the production of different versions of the protein that the encodes gene. We designate the genotype (genetic makeup) of · can an individual wl letters that represent the individual's two copies of each gene (one inherited from its mother the other from its , gene has two father). For example if a alleles designatedA , , & a , the individual could be of genotype AA Aa , , or ad Define alleles One or two more forms of a gene that result in the production of different versions of the protein that the gene encodes. Define The of individual genotype genetic makeup an Define evolution gradually accumulate differences from their ancestors.  Evolution is descent w/modification Darwin proposed that Natural Selection populations accumulate differences over time primarily by & Define natural selection The process by which individuals w/ certain heritable characteristics tend to survive & reproduce more successfully than other individuals because of those characteristics. How can natural selection By favoring individuals w/ different heritable characteristics in explain the accumulation of different population , natural selection can cause populations to differences between diverge genetically from one another over time ; that is each , Populations ? population will accumulate morea more genetic differences · Populations Evolve , individuals do not True or False Either individuals. True in the populations have the traits favored by selection or they don't.  Mechanisms of Evolution Concept 6 2. Natural selection , genetic drift & gene flow , can cause allele frequencies in a population to change over time. Learning objectives 6 2 1 Summarize.. how mutations Mutation & recombination are the sources of new alleles & new contribute to the process of combinations of alleles , thereby providing the genetic variation evolution. on which evolution depends. 6 2 2.. Compare the effects of Natural Selection occurs when individuals w/ certain heritable stabilizing selection & disruptive phenotypic traits Survive & reproduce more successfully than individuals selection on the temporal changes wrother traits. structure of a Natural Selection May favor the average traits (stabilizing selection · in the genetic population or traits near the extremes in a population (disruptive Selection). 6 2 3 Evaluate.. how random Genetic drift which , occurs when random events determine which events can affect populations alleles are passed from one generation to the next can have , through time via genetic drift. negative effects on small populations. 6 2 4 Describe the.. role of gene Gene flow , the transfer of alleles between populations, makes flow another & among populations in terms populations more genetically similar to one can of homogenizing genetic structure introduce new alleles into populations enhancing evolutionary1 ,. as well as enhancing evolutionary Change. What is often the cause of Natural Selection evolutionary change ? What the 4 key processes mutation natural selection genetic drift , & flow are , , gene that influence evolution : What is the source of new Mutation alleles ?  Mutation generates the raw material for evolution Define Phenotype The observable characteristics of an organism. Define mutation Change in the DNA of a gene. What would happen if species each would only have I allele & all members of gene , a lacked mutations ? population Would be genetically identical If this. were the case, evolution could not occur. Define recombination Rearrangements of genetic material during sexual reproduction that result in the production of offspring that have combinations of alleles that differ from those in either of their parents. Natural Selection increases the frequencies of advantageous - alleles & decreases the frequencies of deleterious alleles What are the 3 types (1) Directional Selection natural selection can be (2) Stabilizing selection categorized ? (3) Disruptive selection Define directional selection that favors individuals w/one extreme of a heritable Selection phenotypic trait. Define Stabilizing Selection Selection that favors individuals w/ an intermediate phenotype Define disruptive Selection Selection that favors individuals w/a phenotype at either extreme over those w/ an intermediate phenotype. Define fixation (1) The uptake of the gaseous form of a compound including 20 , , in photosynthesis & N2 in nitrogen fixation by organisms for use in , metabolic functions. (2) With respect to the genetic composition of a population , an allele frequency of 100 %. Genetic drift results from random events Define Gentic drift A process in which chance events determine which alleles are passed from one generation to the next , thereby causing allele frequencies to fluctuate randomly over time ; the effects of genetic drift are most pronouced in small populations.  Gene flow is the transfer of alleles between populations Define Gene flow The transfer of alleles from one population to another via the movement of individuals or gametes. What transfer tends to Gene flow make populations more similar to one another genetically? What tends to produce Gene flow new alleles in a population ?  Adaptive Evolution Concept 6 3. Natural Selection is the mechanism for adaptive evolution. Learning objectives Explain how natural By favoring individuals that have advantageous alleles over individuals · 63 1.. Selection can lead to adaptations that have other alleles natural selection , can cause adaptive evolution in populations. in which the frequency of an advantageous trait in a pop↑. over time. ↑ the frequency of advantageous traits rapidly · Natural Selection can - in days to years depending , on the organism & the selection pressure. 6 3 2 Evaluate the conditions Gene flow can promote the extent to which adapted to ·.. a population is in which gene flow can promote its local environment by introducing new alleles into a population. Gene flow limit the extent to which · or deter adaptions. can also a population is adapted to its local environment by preventing fixation of the favored allele.. 3 3 Describe 6. factors that Constraints on adaptive evolution result from factors such as lack of & ecological trade-offs limit the development of genetic variation evolutionary history , ,. aclaptations in populations. what does the match adaptations between organisms & their environments highlights ? Adaptations are the result of natural selection Define adaptive evolution A processo fevolutionary change in which traits that confer Survival or reproductive advantages tend to increase in frequency in a population over time. Adaptive evolution can occur rapidly Define clines A pattern of gradual change in a characteristic of an organism over a geographic region. Gene flow can promote as well as limit local adaptation is one of the Gene flow factors that can both promote & limit the extent to which a population is adapted to its. local environment Adaptations are not perfect What the number of of Lack genetic variation · are constraints adaptive Evolutionary history · on evolution ? Ecological trade-offs · Define trade-offs An organism's allocation of its limited energy or other resources to one structure or function at the expense of another.  The Evolutionary Concept 6 History. 4 long-term patterns of evolution of Life are shaped by large-scale processes such as speciation , mass extinction , &adaptive radiation. Learning objectives 6 4 1 Describe the process by The genetic of lead to.. divergence populations over time can speciation, which isolation of populations can the process by which one species Splits into 2 or more species· Speciation lead to speciation. requires the evolution of reproductive barriers between populations.. 4 2 Evaluate the roles of 6. The # of species in a group of organisms ↑ when more species are speciation & extinction in determining produced by speciation that are lost to extinction & , ↓ When the reverse the diversity of species. is true· The outcome of this process can be visualized w/ an evolutionary tree· Explain how mass extinctions Biological diversity in mass extinctions, ·.4 3 6. Communities can lose much of their & rapid adaptations have influenced global events in which large proportions of Earth's species are driven to long-term patterns in diversity. extinction in a relatively short time. An adaptive radiation occurs when · a group of organisms gives rise to many new species over a short period of time that expand into new habitat or fill new ecological roles. An adaptive radiations be by factors such as the removal of · can promoted competitor groups by a mass extinction or the evolution of a major new adaptation. The genetic divergence of populations over time can lead to speciation Define Speciation The process by which one species Splits into 2 or more species· When doesSpeciation occur? When a barrier prevents gene flow between 2 or more populations of a species.  can also promote the Genetic drift accumulation of genetic differences between populations. gene flow can ultimately lead Genetic drift ; to the evolution of reproductive barriers & hence to the formation of new species whereas, , - typically acts to Slow down or prevent speciation. The diversity of life reflects both speciation & extinction rates Can the increase ofSpeciation yes also increase the offset by Species extinction ? what does the balance between The net diversity of species within a group. the rates of these two processes determines what ? Define evolutionary tree A branching diagram that represents the evolutionary history of a group of organisms. Mass extinctions & adaptive radiations have shaped long term patterns of evolution evolutio os a Howcan An observed of pattern change The rise & tall of different mass extinctions & adaptive radiations groups of organisms over time has been heavily influenced by what ? Define mass extinction An event in which a large proportion of Earth's species are driven to extinction worldwide in a relatively short time tow many fossil record 5 documents have been recorded ? Define acaptive radiation AneventinwhichagroforanismsSee habitats ecological roles in or new a relatively short time. Joint Effects of Ecology & Evolution Concept 6 5 Ecological. interations & evolution exert a profound influence on one another. Learning objectives 6 5 1 Evaluate how ecological.. Ecological interactions among organisms & between organisms & their processes can result in evolutionary environment can cause evolutionary changes ranging from , allele frequency changes inpopulations. changes in populations to the formation of new species. 6.5 2. Describe how an Evolutionary Change can alter the outcomes of ecological interactions , evolutionary change in a thus having a large influence on biological communities. population has the potential to impact ecological processes. Ecological interactions can cause evolutionary change What3 things do the (1) to gain energy interations in the natural World (2) being change to avoid result from the efforts of organisms? (3) to reproduce Evolution can alter ecological interactions Evolutionary feedbacks of time can occur over short periods