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courselink.uoguelph.ca/d2lle/content/524997/viewContent/1941747/View Tutorial Group Assignment One LR EGB edit -BIOL 2400 (01) F18 Evolution 1) Describe the similarities and differences between the Theory of Evolution as originally formulated by Charles Da...+ 1) Describe the similarities and differences between the Theory of Evolution as originally formulated by Charles Darwin (as Descent with modification) and the NeoDarwinian Theory of Evolution after the 1950s Modern Synthesis (text Chapter 2). Theory component Phenotypic variation among individuals in population Similarit Difference Variation is heritable offspring resemble parents More are born than will survive to reproduce Some "selected" phenotypes survive better and reproduce more in a particular environment Changes in frequency of selected phenotypes in next eneration Natural selection as sole evolutionary mechanism Nature of inheritance of variation - genes Sources of new genetic variation View as TextExplanation / Answer
Theory Component
Genetic drift (also known as allelic drift or the Sewall Wright effect) is the change in the frequency of an existing gene variant (allele) in a population due to random sampling of organisms.
2]The proponents of the synthetic theory maintain that all evolution is due to the accumulation of small genetic changes, guided by natural selection, and that transspecific evolution is nothing but an extrapolation and magnification of the events that take place within populations and species.he core of this synthetic theory restates the two most characteristic assertions of Darwin himself: first, that evolution is a two-stage process (random variation as raw material, natural selection as a directing force); secondly, that evolutionary change is generally slow, steady, gradual, and continuous changes to the most profound structural transitions in life.Hence the whale with shorter hind limbs has an evolutionary advantage that it can catch more fishes and avoid predators and hence these changes are here to stay and will be inherited in the upcoming generations.
Theory Component
Similarity Difference Phenotypic variation among individuals in population Traits vary among individuals with respect to their morphology, physiology and behaviour (phenotypic variation) Genetic variation in populations arises by chance through mutation,genetic variation leads to phenotypic changes among members of a population Variation is heritable:offspring resembles parents Traits can be passed from generation to generation (heritability of fitness) Evolution consists primarily of changes in the frequencies of alleles between one generation and another as a result of natural selection. More are born than will survive to reproduce Evolution by natural selection was first demonstrated by the observation that more offspring are often produced than can possibly survive. The creation of new species, is a gradual process that generally occurs when populations become more and more diversified as a result of having been isolated, such as via geographic barriers, and eventually the populations develop mechanisms of reproductive isolation. Some selected phenotypes survive better and reproduce more in a particular environment In successive generations members of a population are more likely to be replaced by the progenies of parents with favourable characteristics that have enabled them to survive and reproduce in their respective environments. The extrapolation of microevolutionary processes (changes within species) to macroevolutionary trends (changes about the species level, such as the origin of new designs and broad patterns in history). Changes in frequency of selected phenotypes in the next generation Traits come from the interaction of its genotype with the environment.[65] As a result, many aspects of an organism's phenotype are not inherited Evolutionary change is a shift of the frequency of genes in a population, and macroevolutionary trends come from gradual accumulation of small genetic changes. Natural Selection as sole evolutionary mechansim Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. The proponents of the theory maintain that all evolution is due to the accumulation of small genetic changes, guided by natural selection, and that transspecific evolution is nothing but an extrapolation and magnification of the events that take place within populations and species. Nature of inheritence of variation-genes Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on these variations, resulting in certain characteristics becoming more common or rare within a population. genetic variation in populations arises by chance through mutation (it is now known to be caused sometimes by mistakes in DNA replication and via genetic recombination—the crossing over of homologous chromosomes during meiosis). This genetic variation leads to phenotypic changes among members of a population. Sources of new genetic variationGenetic drift (also known as allelic drift or the Sewall Wright effect) is the change in the frequency of an existing gene variant (allele) in a population due to random sampling of organisms.
Sexual selection is a mode of natural selection where members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection).Related Questions
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