S5 S6 Bio Evolution Caltec S.5

DESCENT WITH MODIFICATION Evolution refers to the gradual change in the structure of organisms from simple to complex over a long period of time. This is a branch of science that attempts to describe the various theories concerning the origin of the earth as well as the origin of life on earth and possible ways in which species have originated. Much of the evidences on which these theories are based, be it scientific or theological (religious) are largely metaphysical; i.e., it’s impossible to repeat the exact events discussed in such theories. Theories for the origin of the earth Currently two main theories have been put forward to account for the origin of the earth onto which life exists. The big bang theory, according to this theory, the earth originated from a ball of neutrons that exploded into smaller particles that remained in their orbits around the centre of reaction. The centre of reaction is the sun around which the various planets the earth inclusive orbit. The main limitation of this theory is how nothing can explode into something. Special creation theory, according to this theory, the earth was created from nothing by a super-natural being with divine powers and known as God/Allah. The main limitation to this theory is that it cannot be proved experimental Origin of life on earth In the same way, several theories have been put forward to describe the origin of life on earth. Special creation theory, Life on earth was created by a super-natural being with divine powers and called God/Allah. ExclArchbishop Ussher of Armagh(1650 AD) – October 4004BC from 1st – 23rdwth man @ 0900 Spontaneous generation, Life arose from nonliving matter on a number of occasions by spontaneous generation Such nonliving matter was said to contain an active principle that could give rise …