Evolution is the process by which a living species, develops and diversifies from its predecessor through small incremental changes over time as the species adapts to its current environment.
Through the process of evolution, small incremental changes occur to the organisms DNA, which over time, may also change the species characteristic appearance. When enough small changes occur, eventually a point is reached where the DNA of the species, diverges enough from its original predecessor to the point where we could conclude that the organism has evolved into a new species.
Evolution occurs by several mechanisms.
Mutations: Genetic alterations to an organisms DNA which results in changes to the organisms characteristics. Mutations can be both positive and/or negative in regards to the organism’s survival.
Natural Selection: The process in which organisms that are better adapted to their environment, tend to survive and reproduce and ultimately pass on their adaptive traits to their offspring. Overall, beneficial traits tend to increase within a given population.
In order for a trait to undergo natural selection it must be beneficial to the organism and increase its chances of survival and reproduction and it must also be heritable so that it can be passed on to the organism’s offspring.
Some examples of natural selection in humans
Pigmentation differences in skin tone corresponding to the population’s relationship with the sun. Darker or lighter skin pigmentation is selected for depending on the environmental impact that the sun has on the organism.
Lactose tolerance in humans due to the domestication of cattle.
Malaria resistant genes are more common in populations where malaria is prevalent in the environment.
Adapting to a Changing Environment: What About Mars?
Though the evolutionary process is constantly taking place, the most noticeable changes to a species characteristic traits tend to occur when there are drastic changes to the organism’s environment. Though humans are still evolving to some degree, since we have dispersed across the globe and basically mastered our environment, our evolutionary adaptation as a whole, has likely slowed down significantly.
However, there are talks about colonizing the planet of Mars, a notion that raises a lot of interesting considerations in terms of human evolution.
Since the planet of Mars has a completely different environment compared to earth, human colonizers would naturally be forced to adapt to the planets conditions in order to survive and reproduce. As such, if humans colonize Mars, over time we would likely see massive changes to the species genetics, as well as their physical appearance.
After a few tens (or hundreds) of thousands of years, the humans of Mars would likely develop into an entirely different species.
Examples of Changes that may occur to Human Colonizers.
Changes to the eyes and skin as the species adapts to the differing effects of the sun on the planet.
Changes to the body due to differences in the planets gravitational force.
Changes to the lungs and breathing mechanism as the species adapts to the existing atmosphere.
Changes to the digestive system as the species adapts in tandem to the evolving food source(s) of the planet (i.e. as plants and animals evolve so will humans).
These are just a few of the changes that may occur to the human species over time as they adapt to the conditions of the planet.