SpringBioTest.docx - Define evolution Evolution is the...

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Define evolution: Evolution is the cumulative change in the heritable characteristics/allele frequency of a population Through time, species accumulate differences; as a result, descendants differ from their ancestors New species arise from existing ones Descent with modification Outline the four components of evolution (Change in allele frequency over time) Mutation Migration Natural Selection Genetic Drift Outline the components required for natural selection : Populations tend to grow exponentially Overpopulation gives competition and a struggle for existence Variation exists in population Phenotypic variation must exist among individuals in a population Natural selection works by favoring individuals with some traits over individuals with alternative traits If no variation exists, natural selection cannot operate Best fit individuals survive and pass on their traits to offspring (Differential survival and reproductive success) Bc of phenotypic or behavioral differences, some individuals are more successful than others in producing offspring Many traits are phenotypically variable, but individuals exhibiting variation don’t always differ in survival and reproductive success Evolution occurs on the population (NOT individual) Mutation can occur on the individual But phenotypic variation must have a genetic basis, cannot be from individual environmental effects Explain the relationship between mutation, adaptation and natural selection. Give an example in your answer.
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Adaptations are changes or processes of changes by which an organism or species becomes better suited for its environment. A mutation is an alteration of the DNA sequence, which can sometimes be more advantageous in surviving a certain environment Ex) Giraffe with a slightly longer neck had originally been a mutation, but was proven to be advantageous for fighting and food Natural selection is the process by which organisms with more advantageous traits (being camouflaged, being covered with the correct outer covering for the temperatures of that environment, stronger/ larger/ or faster to fight off or run from predators, etc.) are more likely to survive in a particular environment. Likewise, organisms less advantageous traits are more likely to die due to the pressures exerted by the environment (such as temperature, predators, illness, etc.). Therefore, the organisms with the advantageous traits that survive are more likely to survive to find a mate and reproduce. Thus, the advantageous traits are passed down to future generations. Explain two examples of evolution in response to environmental change; one must be antibiotic resistance in bacteria Antibiotic resistance in bacteria Results from transfer of a gene that gives resistance to a specific antibiotic by means of a plasmid to a bacterium Some bacteria will then have this gene and become resistant to the specific antibiotic
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