Which of the following is an assumption of the molecular clock?
The “molecular clock” method assumes that changes in DNA accumulate at approximately constant rates over time. One explanation is that species might undergo genetic changes long before those changes are reflected in the body plan.
What does the molecular clock used to determine how closely two species are related?
Molecular clocks are used to determine how closely two species are related by calculating the number of differences between the species’ DNA sequences or amino acid sequences. The fewer the differences, the less time since the species split from each other and began to evolve into different species (Figure below).
What are 5 factors that can change the frequency of alleles in a population?
Allele frequencies in a population may change due to gene flow, genetic drift, natural selection and mutation. These are referred to as the four fundamental forces of evolution. Note that only mutation can create new genetic variation. The other three forces simply rearrange this variation within and among populations.
What are the factors that influence gene frequencies?
role in natural selection Gene frequencies tend to remain constant from generation to generation when disturbing factors are not present. Factors that disturb the natural equilibrium of gene frequencies include mutation, migration (or gene flow), random genetic drift, and natural selection.
What are the factors that affect gene frequencies?
The four factors that can bring about such a change are: natural selection, mutation, random genetic drift, and migration into or out of the population. (A fifth factor—changes to the mating pattern—can change the genotype but not the allele frequencies; many theorists would not count this as an evolutionary change.)
What causes an allele frequency to change?
Natural selection, genetic drift, and gene flow are the mechanisms that cause changes in allele frequencies over time. When one or more of these forces are acting in a population, the population violates the Hardy-Weinberg assumptions, and evolution occurs.
Do humans continue to evolve until now?
It is selection pressure that drives natural selection (‘survival of the fittest’) and it is how we evolved into the species we are today. Genetic studies have demonstrated that humans are still evolving.