OUR PLANET supports a great diversity of species. This is easy to recognize as anyone can easily  list many types of insects, birds, fishes, snakes, frogs toads, palms, orchids, roses, grasses, fruit plants, mammals etc. Species of plants and animals have evolved, undergoing small changes over millions of years which make them adapted to live in particular places or habitats.  These may range from being extremely cold to very hot, and from being very wet to very dry.

The different species, each occupying their own special habitats on Earth, are referred to as ‘species diversity’. Each species is well suited to finding food and mates in its particular habitat, so that there is continuity of its own kind.

Species diversity is easy to recognize, however, this does not mean that all members of the same species are exactly alike. In fact, within a particular species, e.g. dogs and yes, humans, there is much variation – this is known as ‘genetic diversity’.

Genetic diversity is caused by differences in genes or chemical codes present in individuals. Genes are passed on to an individual from its parents, and are responsible for the differences we see in individuals of the same species. For example, in the thousands of species of birds found in the world – each has their own characteristic plumage, bill shape, and other particular adaptation.  Looking at wild cats, for example, there are many different species of cats found in the world. Genetic diversity allows for the unique features observed in each different species of wildcat. Jaguars, Ocelots, Lions, Tigers, and Cougars have genes that separate them from each other, thereby  allowing each to be of a certain build, determining whether they would have a mane or be spotted.

But genetics also plays an important role, even at the individual species level also! Individually, because of genetics, we are each unique. In the plant and animal world, it is sometimes hard to visibly distinguish one individual from another of a particular species. However, there are a few examples where genetic diversity within species can be easily recognized. Giant River Otters, though now an endangered species, are found in healthy numbers in Guyana’s rivers. Each individual otter can be easily identified by the shape of a white, creamy patch under its throat, referred to as its ‘bib’.

Importance of Genetic Diversity
Genes play an important role also in an individual’s ability to adapt to environmental conditions. While some individuals might be able to tolerate an increased load of pollutants in their environment, others, carrying different genes, might suffer from infertility or even die under the exact same environmental conditions. This leads ultimately to the process of natural selection which dictates the survival of the fittest. This process of natural selection leads to the loss of genetic diversity in certain habitats. However, the individuals that are no longer present might have carried genes for faster growth, or for the ability to cope better with other stress factors.

In the animal world, it is evident in species that during the mating season, there is always a desire for female species to select those males that are strongest, i.e. have the best genes. In some species, we observe that one male is favoured by several females, which contributes to the continuity of his genes and ultimately its species.

Threats to genetic diversity
Human activities could have negative impacts on genetic diversity. Most alarming is the degradation of wildlife habitats which leads to a reduction of gene pool and thus an increase in the likeliness of inbreeding and disappearance of individual species that may be carrying genes for pollutant tolerance, etc.

Another negative activity is the release (whether intentional or not) of farmed species, such as fish, into the wild. With a limited gene pool in the natural environment, species may be unable to adapt to environmental stresses.

Genetic diversity also includes the differences observed between distinct populations of a single species. The greater the genetic diversity within a population, the better it is for the survival of the species. Cheetah populations have become very small, and as such there is very little genetic diversity within and among populations. This places the cheetah at risk of becoming extinct in the face of any threat, e.g. disease, climate change.

Earth’s rich biodiversity is greatly due to the genetic diversity which has allowed species to adapt to almost every possible environment. We all can contribute towards saving our biodiversity if we wish to continue to appreciate its splendid diversity!

Reference
http://www.biodiversity.ru/coastlearn/bio-eng/boxes/geneticdiv.html

You can share ideas and questions by sending letters to: ‘Our Earth, Our Environment’, C/o EIT Division, Environmental Protection Agency, 7 Broad and Charles Street, Charlestown, GEORGETOWN or email eit.epaguyana@gmail.com