All of the organisms that live on the planet are subject to the pressures of natural selection. Humans have the ability to change their environment and shape it to suit their needs. Even though humans can change their environment they are still subject to the pressures of natural selection.
The changes that humans make to their environment do not cancel natural selection the changes only change the outcome.
As humans change their environment so that it is easier to live in natural selection changes humans so they are better suited to the new environment. The changes caused by natural selection that are most easily seen would be the behavioral changes. As humans create new technologies and populate the planet humans have had to make and will continue to make behavioral changes. Humans that can not make the necessary behavioral changes will find it difficult to survive.
There are different patterns in evolution. When unrelated organisms living in similar environments evolve similar characteristics it is called convergent evolution. An example of convergent evolution would be the maras of South America and the European rabbit. They maras and the rabbits are not related but they look similar because they evolved in similar environments (Pruitt & Underwood, 2006).
When species are closely related and drift apart because they are living in different territories it often results in new species this is called divergent evolution (Pruitt & Underwood, 2006). An example of divergent evolution would be the “the small Hyracotherium evolved through several intermediate species, not only into today’s horses but into today’s zebras and mules Today’s “horses” have not only diverged from Hyracotherium, but from each other.
When a species moves into a new environment and evolves into several new closely related species it is called adaptive radiation. An example of adaptive radiation would be Darwin’s finches (Pruitt & Underwood, 2006). Co-evolution is when the evolution of one species influences the evolution of another species.
A good example of co-evolution would be the changes being forced on organisms due to the evolution of humans. As humans evolve and change the environment of the entire planet other organism are being forced to change to survive. The changes humans are forcing on the other organisms will have implications for future humans. Many of the other organisms can not evolve as fast as humans are changing the environment this will mean that future humans may be faced with a planet that does not have many of the organisms that we share the planet with today.
Reference
Pruitt, N. L., & Underwood, L. S. (2006). Bioinquiry: Making connections in biology (3rd ed.). Hoboken, NJ: John Wiley & Sons, Inc.