Which best summarizes the concept of natural selection?
Answer. The fittest organisms survive and reproduce best summarizes the concept of natural selection.
What causes natural selection occur?
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.
Why does natural selection not occur in population?
Natural selection can only occur if there is variation among members of the same species. Variation in a population results from mutation and the recombination of alleles during meiosis and fertilization.
Can natural selection occur if there is no variation?
Evolution by NATURAL SELECTION cannot occur if there is no variation within a species, because that theory depends on variation within the species causing better adaptation to new environments – better ‘fitness’. Elephants will become extinct if their food dwindles as they cannot adapt to different food.
What if there is no variation in species?
Without genetic variation, a population cannot evolve in response to changing environmental variables and, as a result, may face an increased risk of extinction. But if they do not exist — if the right genetic variation is not present — the population will not evolve and could be wiped out by the disease.
What would happen if natural selection did not occur?
If all of the organisms within a population were completely identical, it would not be possible for natural selection to occur; if all gazelles ran the same speed, then there would be no “faster” individuals to avoid the clutches of predators.
How does diseases affect natural selection?
From an evolutionary perspective, infectious diseases have probably been the primary agent of natural selection over the past 5000 years, eliminating human hosts who were more susceptible to disease and sparing those who were more resistant.
How do you think diseases can affect natural selection quizlet?
How do you think diseases can affect natural selection? The species that has develops amenity to certain bacteria will have a higher chance of survival than others.
Why do you think that natural selection has not removed the HFE gene from the population?
When carrying two copies of an allele is disadvantageous, but carrying only one copy is advantageous, natural selection will not remove the allele from the population — the advantage conferred in its heterozygous state keeps the allele around.
Why do so many harmful genetic diseases still exist?
Introduction: Why Harmful Alleles Persist Because harmful alleles are often recessive alleles, they can persist in a population almost indefinitely. And, even harmful dominant alleles, despite selection against the phenotypes they produce, can also often continue to persist in gene pools.
Is it possible to predict allele frequencies that are a result of genetic drift?
Nope! In fact, sometimes evolution just happens by chance. In population genetics, evolution is defined as a change in the frequency of alleles (versions of a gene) in a population over time.
How can natural selection maintain harmful alleles in a population?
How can natural selection maintain harmful alleles in a population? Natural selection can only select against phenotypes. If the dominant phenotype is selected for, heterozygous individuals will retain the recessive allele in the population.