Answer:
Explanation:
friction between two rock surfaces grinding away minerals.
Answer:
The placebo effect
Explanation:
The placebo effect in psychology refers to a situation in which participants in a research receive beneficial effects due to the administration of an inactive substance or a sham treatment. The positive beneficial effect received can then be attributed purely to believe and not to the treatment itself. A placebo treatment could produce a real healing effect like a true medical or psychological treatment.
The participants who received the sugar believed it to be a memory enhancing treatment hence the slight increase in memory capacity due to placebo effect.
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:
India was a separate continent until 45 million years ago
Explanation:
India was part of the Gondwanaland continent which was one of the two remnants of Pangaea, while Asia was part of Laurasia, the other remnant of Pangaea. Because these two land masses were separate, the animals and plants were evolving separately for millions of years. India further separated from Gondwanaland, and it was actually a very large island for millions of years, resulting in isolation and development of unique animals and plants because of it. As India was moving it reached Asia and collided with it, thus becoming one land mass. Some Asian species managed to get in India, but mostly in its northern parts, while the central and southern parts remained dominated by the indigenous species. The Himalayan Mountain Range that formed because of the collision also helped in preserving lot of the indigenous species as it became a natural barrier that most species can not go through.
