Biodiversity and Natural Selection: The Human Factor

What is biodiversity? It can mean many things, however, it essentially describes the variety found in all living organisms. It can mean the variety of habitats or species within an area or it can mean the genetic variation found within one species. It is this genetic diversity, combined with genetic drift due to mutations, that enables the process of natural selection to occur both within a population and between populations.

Humans affect biodiversity by over harvesting various species, introducing alien (both invasive and non-invasive) species to new habitats, by creating pollution, by altering, destroying, or fragmenting habitats, and by interaction effects caused by the links between the species in an ecosystem. All of these changes can affect individual species negatively an cause a reduction in biodiversity. In order to preserve biodiversity in various species and in their environments it is necessary for humans to begin to alter their conduct and become more mindful of the life around them.

Natural selection is a component of the theory of evolution. This theory, credited to Charles Darwin, explains the effect of environmental pressures on the physical characteristics in any given population. Typically those characteristics which make it easier for a species to survive will also cause it to reproduce successfully and thus will become more prominent in subsequent generations. Those characteristics that are unsuccessful will eventually be bred out of the species.

Biodiversity is an important aspect of natural selection. When there are changes in the environment a diverse population of organisms is better able to adapt and thrive in the new environment. If the biodiversity is limited, then both species and ecosystems will not be able to meet new environmental challenges and the populations will decrease or become extinct. If, instead, biodiversity in the species is extensive then those subjects that are best suited to the environment will survive and pass on their genes to future generations. The process of natural selection will determine which of the species survives.

Conversely, natural selection can also limit the biodiversity of a species in the short term. When the subjects that are not well suited to the new or changing environment die out, the biodiversity of the species becomes more limited.