Thomas Malthus’ essay on population, “An Essay on the Principle of Population,” published in 1798, had a big influence on Charles Darwin.
Malthus argued in this essay that population growth would eventually outstrip the earth’s ability to support it, resulting in widespread suffering and poverty.
Darwin read Malthus’ essay while developing his theory of natural selection, and it influenced his thinking about the struggle for existence and how organism populations adapt to their environments.
Darwin incorporated Malthus’ ideas about the limits of population growth and the consequences of overpopulation into his theory of natural selection as the driving force behind species evolution.
Malthus’s argument that populations grow exponentially while resources grow at a slower rate influenced Darwin’s view of resource competition and the ways in which species adapt to their environments in order to survive.
This concept of competition and the struggle for existence became central to Darwin’s theory of natural selection and remains so in modern evolutionary theory.
In other words, Darwin believed that species evolve in order to compete for resources and survive in their environments.
For example, a species might evolve longer legs to reach food more easily, or sharper teeth to catch prey more effectively.
To summarise, Malthus’ ideas about population growth and the struggle for resources influenced Darwin’s theory of natural selection and the way species to adapt to their environments in order to survive.