A series of theories of evoiution given by Charles Darwin

 

Charles Darwin was a British Naturalist and worked suddenly on Evolution. He conducted a sea voyage  around the world on his own made ship HMS Beagle.

During his Sea voyage he visited Galapagos island in South America. On this island he observed various changes in species, especially in the beak of birds. These were named as Darwin finches which are also example of Adaptive radiation. Darwin thought about how these changes appeared in species on this island.

👌👌Remember - Darwin had been influenced by an essay on Population written by Thomas Malthus.

These changes were named as variations Although Darwin could not explain clearly the significance of these variations but Darwin put several theories by observing the changes in species on this island. These theories were milestone in field of evolution. The Darwin theories regarding these changes for evolution are as follows-

Over production - Darwin observed that when food and shelter or resources are unlimited than every species increase its population in exponentially. This is called over production. And after a specific time, resources are limited for such exponential grown population.

Struggle for existence - one population of any species is  increased in size exponentially than resources are limited for those populations . As a result there is a competition for food and shelters and individuals struggle for food and reproduction. 

Survival of the fittest - Now  those individuals that  make changes in their foraging habit and develop any new character, that individual is capable of surviving in such a competitive habitat. Those individuals with newly developed characters are classified as survival of fittest.

Natural selection - The individuals with new characters are selected by nature to survive and reproduce in such habitats.The  new developed characters make individuals successful in terms of reproduction  and survival. 

Origin of new species -

On the basis of new developed characters, species are different from the older one and the origin of new species takes place.

Darwin used term variation for new changes those are adopted by the individual during unlimited resources. On the basis of his work , Darwin wrote a book " origin of species".