Answer:
- 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.
Both glycerophospholipids and sphingolipid structures are asymmetrically distributed in the two layers of the phospholipid bilayer. Sphingolipids are membrane lipids that have a ceramide backbone while glycerophospholipid has glycerol present in its membrane lipids. Sphingolipids may or may not be present.
Polypeptide is another name for a protien.
Answer:
An atom's electronegativity gets higher as you move up in the periodic table. Thus, the atoms in the top right have the highest electronegativities and the atoms in the bottom left have the lowest ones.
