I would say the first one a comet. :)
Answer:
Two genes on the same chromosome being inherited.
Explanation:
The decomposers are of two kinds, aerobic decomposers and anaerobic decomposers. The aerobic decomposers need the oxygen from the air to break down the dead and decaying matter into simple salts, sugars and hydrocarbon gases. The anaerobic decomposers do not require oxygen for the break down of dead and decaying matter. They break down the matter into various forms of hydrocarbons, sulphides and nitrogenous compounds.
When a dead and decaying matter gets buried deep within the Earth where there is an absence of the decomposers, it takes the form of crude oil, coal, peat, asphalt, and natural gas. The matter gets compressed by the weight of the rocks above and changes its form.
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.
