PPT-Gene Frequency and Natural Selection

Spring Feb 2015 Gene Frequency Random g enetic mutations occurs Inherent Variation Sexual reproduction Relationship between Gene Frequency and Natural S election Natural Selection. ,. and the rise of biological complexity. Selection needs variation. Most species have great variation in . reproductive success. .. This variation is the basis for natural selection. that means changes in gene frequencies. . Evolution- changes in the characteristics of groups of organisms over time . Charles Darwin was the first to propose a feasible . mechanism. for evolution. It is called . natural selection. . . Evolution by Natural Selection is a theory. . and Evolution. DNA and Heredity . As seen in the section on Taxonomy, modern classification of organisms is being shaped by our understanding of genetics; of DNA.. DNA is a polymer (many molecules attached to one another) of nucleic acids. A nucleic acid is monomer (one molecule) that contains three parts:. OBJECTIVES. Today, you will be able to…. Explain the process of evolution by natural selection. Explain adaptation. What exactly is “evolution” in THIS class?. Evolution. - a change in the . GENETIC. Relative fitness in relation to. Natural selection. Natural selection often has “survival of the fittest” and the “struggle to survive” associated with it, but it doesn’t necessarily mean direct physical conflict between two organisms.. 8.6. Starter. Define natural selection. Individuals with particular characteristics have a greater chance of survival than individuals without those characteristics, which are therefore more likely to breed and pass on the genes for these characteristics to their offspring.. Natural Selection does not always proceed in the expected direction, because several forces could interfere with the action of Natural Selection. Constraints on Natural Selection. Genetic . Variation. Directional selection on allele frequency. Selections alters the allele frequency of the pop.. FF has highest fitness. SS has lowest fitness. The rate of change in allele frequency is determined by the strength of selection (i.e., the fitness differential of the phenotypes). What is natural selection?. It’s the . process whereby organisms better adapted to their environment tend to survive and produce more offspring. . The . theory. of its action was first fully . explained . Evolutionary Ideas. A. lthough Darwin is given much credit for evolutionary theory, he was not the first person to come up with the idea.. Evolution is the change in a population over time.. The concept of evolution had been discussed for more than 100 years prior to Darwin’s theory.. According to evolutionists. Characteristics of Organisms in the Galapagos Islands compared to nearby South America. Darwin hypothesized that animals came to the . Galapagos. from the . mainland. and they became . A. Species overproduce offspring that may survive an environment.. B. There is little variation among members of a population.. C. Competition for resources, mates, and space among species leads to a struggle to survive.. Charles Robert Darwin. . (1809-1882) was an English naturalist who . born on 12th February, 1809. at Shrewsbury, England. . He went on . voyage. . (trip, expedition, tour). for five years (1831 to 1836) and . wallace. and was explained in book “ on the origin of species by means of Natural Selection . . Darwin put the theory based on his observations as he travelled round the world on the ship Beagle..