Interruption in the genetic flow between separated groups
The emergence of new mutations in each of the groups, and their accumulation in time. Slow and gradual differentiation between populations.
Genetic divergence by natural selection and reproductive isolation
Prezigotic isolation mechanisms
Explanation:
Allopatric speciation consists of the geographic separation of a continuous genetic background that can give place to two or more new geographically isolated populations. These separations might be due to migration, extinction of geographically intermediate populations, or geological events. In this speciation, some barriers impede genetic interchange, or genetic flux, as the two new groups that are separated can not get together and mate anymore. These barriers might be geographical or ecological.
The process of allopatric speciation involves different steps that affect organisms:
The emergence of the barrier.
Interruption in the genetic interchange
The occurrence of new mutations and their accumulation in time in each population. Slow and gradual differentiation.
Genetic divergence by natural selection and reproductive isolation makes it impossible for the two groups to mate even if the barrier disappears.
Prezigotic isolation mechanisms will be favored by selection if occurs a secondary contact between the new species in formation.
What percent of potassium-40 remains undecayed in a rock that is 3.9 billion years old? The 3.9 billion year old rock has undergone three half-lives (3.9 divided by 1.3 = 3). After 3 half-lives, 12.5% of the potassium-40 remains undecayed.
The answer is B a net 2 ATPs are always generated per glucose regardless of its source
Explanation
Glycogen breaks down in the muscle so as to have enough glucose for muscle contraction and it produces 2ATPs
Glycogen also breaks down in the liver to release enough glucose which gets to the blood stream and is then taken up by other cells. It also produces 2ATPs at the expense of 6ATPs
