• Branching descent and natural selection are the two key concepts of Darwinian Theory of Evolution.

• Branching descent – It is defined as a process by which new species originate from a single common descendant. Hence the various life forms can be represented as branches coming out of the same tree.

Example of branching descent

• Natural Selection is a process in which heritable variations enabling better survival are selected and passed on from parent to progeny over generations. That is nature selects only those traits which help an organism to survive changed conditions.

• Other important concepts in Darwin Theory are: Over-production of living beings, struggle for existence, survival of fittest.