Adaptation and Evolution

Adaptation is a process by which organisms become better suited to their environment to increase chances of survival and reproduction.
This process occurs over generations, as random changes in the genetic material of a population accumulate and beneficial changes become prevalent.
These adaptations can be anatomical (related to bodily structure), physiological (related to bodily functions), or behavioural (related to the way an organism behaves).
It’s important to remember that individuals don’t adapt per se but rather, populations evolve over time as individuals possessing beneficial traits have a better chance to survive, reproduce, and pass on those traits.

Natural selection is a key mechanism of evolution and involves differential survival and reproduction of individuals due to differences in phenotype.
This concept was first proposed by Charles Darwin and is often summarised as survival of the fittest.
Four key factors for natural selection are overproduction of offspring, genetic variation, struggle for existence, and differential survival and reproduction.
The result of natural selection is the adaptation of populations to their environment, leading to changes in the characteristics of species over time.

Evolution is the process by which different kinds of living organisms have developed and diversified from earlier forms during the history of the earth.
It is a gradual process, occurring over long periods of time, and may result in new species (speciation) due to accumulation of genetic changes.
Evidence for evolution includes the fossil record, which shows a progression of forms over time; the geographic distribution of species, which reflects the movement and adaptation of species; and homologies, or similarities in structures, which can indicate common ancestry.
Evolution drives biodiversity, as it gives rise to new species and thus increases the variety of life on Earth.

Speciation is the formation of new and distinct species in the course of evolution.
This process often occurs through allopatric speciation, whereby a population is divided by a geographic barrier (e.g. mountain, river), leading to genetic isolation and divergence over time.
It can also occur via sympatric speciation, where new species evolve from a single ancestral species while inhabiting the same geographic region.
Both forms of speciation contribute to biodiversity by increasing the number of species present in an ecosystem.

Genetic drift refers to changes in the allele frequencies of a population due to chance events.
This process can lead to the loss of genetic variation within populations.
Genetic drift often has a more significant effect on small populations, whereby chance events can make a big difference to the genetic makeup of a population.
Both genetic drift and natural selection drive evolution and biodiversity by changing the genetic makeup of populations and thus leading to new adaptations and speciation.