The earth is not a completely static place. Over the eons, climates change, and so a beautiful lush forest can slowly start to dry up, and an animal species living happily in that forest either has to retreat to the higher elevations on the mountain sides (where many populations may get isolated, and thus turn into multiple species), or it has to learn to adapt to life on the drier plains. But it's not just this long-term change in climate conditions that can radically change an ecological environment (Reece, Campbell, 2006).
Some new fungus could arrive in a forest that decimates a certain kind of plant, which may be the main food source for a certain kind of insect, and its extinction may disrupt the polination of other kinds of plants and the birds that live in them or feed on that insect, and so on ... and so the arrival of that single new fungus may cause a wide array of plants and animals to have to either evolve to a changing environment, or go extinct. So in short, time changes ecological environments, which spurs evolution, which further changes that environment, and so on.
Over long time span of time, competitive displacement may lead to evolutionary changes. This occurs as species displaced to marginal environments develop to become better acclimatized to those situation, and they may eventually become new species. Competitive displacement is accepted to be the prime force leading to the evolution of species swarms on isolated islands such as those of crop flies (Drosophila spp.) and honeycreepers (Drepaniidae) on the Hawaiian Islands and Darwin's finches (Geospizinae) on the Galapagos Islands.
Q-2 Hypothesis of Plant Growth on High and Low Elavation
Awell-designed and constructed trial will be robust under interrogating, and will ...