Answer
Evolution: The change in genetic composition of a population of organisms
Natural selection: The theory that variation exists in every population and that in every population there are individuals that have genes that confer survival advantages on them-- camouflage, disease resistance, physical stature, fertility etc. These advantages result in greater reproductive success for the advantaged individuals and the genetic composition of the group will gradually change to be like them until it becomes a new variety, sub-species or species. Examples : development of antibiotic resistance by some bacteria, evolutionary change in beak shape of some Galapagos finches, development of resistance to quinine by malaria parasite (Plasmodium).
Work Step by Step
Selection Pressure: . Selection pressures are natural agents that cause organisms to evolve in a certain
direction. Examples of these agencies are climatic factors, food availability, predators,
and diseases .
Adaptation: Development of features-- anatomical,physiological, and behavioral-- under selection
pressure, that facilitate survival of organisms and increase in a population.
Examples : opposable thumb, stereoscopic vision, flexible shoulder joint -- in
chimpanzees, long necks of giraffes, and loss of legs by snakes.
