In: Biology
Darwin's theory of evolution
In 1859, Charles Darwin put his theory of evolution (change) and adaptation.
Evolution means change in character which heritable to successive generations.
Adaptation is process in which organisms become more able to live in their habitat ( place).
Darwin's theory principally based on Natural selection process.
What is natural selection?
Natural selection is the process by which organisms having better adaption to specific environmental pressures, as predators, changes in climate, or competition for food or mates.They become able to survive and reproduce greatly in comparison to others.
So, nature chooses those characters which are capable of surviving and pass them to next generation simply called natural selection.
Darwin defined natural selection as the principle by which each slight variation or any change , if it is useful then it preserved.
Example,
Giraffes have long necks and some have short ones.
If anything caused & shrubs on which short giraffes feed on present down side if they die out, then the giraffes with short necks would not get enough food.
So, after a few generations, all the giraffes would have long necks.
In given example also nature selects those characteristics which make organisms to fittest to survive & losses those characters which is not useful for survival & reproduction.