Question

What is species distribution?

Answer 1

According to May’s estimate, the total number of species present on this planet is roughly around 7 million. But all these species are not found in the same place. The distribution of organisms on this planet is very much uneven. One might have heard the term endemic species. It means that if a species is endemic then it is only found in a selective area and nowhere else in the world. But one should wonder why it is so and if it is, then what influences this distribution?

Complete answer:
By definition, species distribution is the manner in which a biological taxon is spatially arranged. The biological taxon may be at the species level, genus level, or even at the family level. For example, Asiatic lions are found in the south-eastern continent (India). This is an example where the biological taxon is a species. Now lions are found over the Asian and African continents. This was an example of the distribution at the genus level.
Now, a set of biotic and abiotic factors influences this species distribution.
There are three main types of abiotic factors:
1. Climatic factors consist of sunlight, atmosphere, humidity, temperature, and salinity;
2. Edaphic factors are abiotic factors regarding soil, such as the coarseness of soil, local geology, soil pH, and aeration; and
3. Social factors include land use and water availability.
Biotic factors such as predation, disease, and inter and intra-specific competition for resources such as food, water, and mates can also affect how a species is distributed.
For example, biotic factors in a quail’s environment would include their prey (insects and seeds), competition from other quail, and their predators, such as the coyote.

Note:
The learners should be able to distinguish between three terms- Range, Distribution, and, Dispersion. These three terms are used interchangeably very often in biology but are not with the similar meaning. In biology, the range of a species is the geographical area within which that species can be found. Within that range, distribution is the general structure of the species population, while dispersion is the variation in its population density.