EVOLUTION

This refers to the gradual development of complex organisms from simpler ancestral types over a long period of time. This is caused by changes in the populations resulting from inherited variations in individuals in successive generation.

Evolution begins with the production of new species which gradually differ more and more from each other until new genera, families, classes, have evolved.

Origin of life:

The exact origin of life is not known. How ever some theories have been put forward to show the origin of life which include;

Steady state theory: this suggests that life has no origin and it has been existence.
Spontaneous generation: This indicates that life arose from non living matter on numerous occasions.
Special creation: this indicates that life was created by a supernatural being at a particular time.
Cosmozaon theory: this suggests that life arrived on this planet from else where.
 Biochemical evolution:  Most accepted theory by scientists. It suggests that life arose from according to biochemical and physical laws which lead to formation of certain macromolecules which make up DNA and body cells.


Evolution theory explains that the different species of organisms existing today arose from common ancestors which were originally primitive but gradually under went changes along different evolutionary lines in different environments in order to survive in those environments. The trend of evolution there fore, is gradual change from primitive form of life to advance d form of life.