Answer:
Species separated by a physical barrier for a long time, suffer allopatric speciation, so they can not interbreed anymore.
Explanation:
Allopatric speciation consists of the geographic separation of a continuous genetic background giving 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 flow, as the two new populations that are separated can not get together and mate anymore. These barriers might be geographical or ecological.
Vicariance is the geographical separation of an original population into two or more new groups. Discontinuities in the physical environment like rivers, mountains, water, etc., are physical barriers that impede genetic flow between the separated groups.
The process of allopatric speciation involves different steps:
- 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 favored by selection once occurs a secondary contact between the new species in formation.
An adaptation-----------------------
These abnormalities occur in the serotonin system which reduces and/or inhibits control in their movement. This disruption of the neurotransmitter causes them to act maladaptively. Thank you for your question. Please don't hesitate to ask in Brainly your queries.
Answer:a) decreased chromatin condensation
Explanation:
During eukaryotic cell division a chromatin becomes obvious and it is simply a mass of genetic material made up of DNA and proteins which condenses to form chromosomes.
The chromatin primarily function in the compression the DNA into a unit so compacted that will be so tiny and can fit within the nucleus.
Chromatin condensation is driven by condensins and interactions between histones.
Condensins however, are large protein complexes whose central role in cell division is chromosome organization and segregation.
Chemical manipulation as stated above is decreases the rate of chromatin condensation.
