What events occur that contribute to genetic variation?
Genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism’s offspring).
What are the 3 main sources of genetic variation in organisms?
For a given population, there are three sources of variation: mutation, recombination, and immigration of genes. However, recombination by itself does not produce variation unless alleles are segregating already at different loci; otherwise there is nothing to recombine.
Which of the following must exist in a population in order for natural selection to act?
Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.
Which statement best describes how reproduction lead to natural selection in a population?
Answer: The correct answer is C or Organisms overproduce offspring, so only some survive and pass on their traits….
What allows natural selection?
What are the 5 key elements of Darwin’s theory of natural selection?
Terms in this set (6)
- five points. competition, adaption, variation, overproduction, speciation.
- competition. demand by organisms for limited environmental resources, such as nutrients, living space, or light.
- adaption. inherited characteristics that increase chance of survival.
What is the difference between Darwin’s theory and Lamarck’s theory?
Darwin and Lamarck were both scientists who tried to understand evolution. Darwin’s theory became accepted because it had more evidence that supported it. Lamarck’s theory suggest that all organisms become more complicated over time, and therefore doesn’t account for simple organisms, such as single-cell organisms.
What feature of the environment enabled the development of long neck of the giraffe according to Lamarck’s theory?
Use and Disuse According to Lamarck’s theory, a given giraffe could, over a lifetime of straining to reach high branches, develop an elongated neck.