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.
Answer:
D. as an arrangement of four chemical bases
Explanation:
Our DNA is made up of 4 chemical bases (adenine, thymine, guanine, cytosine).
Answer:
The correct answer is D: "<em>Apes have a Y-5 pattern of cusps, whereas Old World monkeys have a bilophodont pattern</em>".
Explanation:
Apes and old world monkeys only have four kinds of teeth: <em>two incisors, one canine, two premolars, and three molars</em>. This dental formula is 2.1.2.3.
The old world monkeys characterize for having molars with four cusps joined by ridges. They have bilophodont teeth with better crushing, shearing and wearing capabilities than apes.
Apes´molars have 5 cusps, a Y-shaped space between those raised points, and no transverse lophs. These characteristics are known as the Y-5 pattern.
Answer:
Ionic bonding When metals react with non-metals, electrons are transferred from the metal atoms to the non-metal atoms, forming ions . The resulting compound is called an ionic compound .
Explanation:
