Question

What do you understand about a species? Outline the ways in which new species arise.

Answer 1

Every life form on earth belongs to a particular species. Species is the biggest gene pool that can be found on this planet. Humans, black bears, and moose are all different species of organisms. These organisms are grouped together while classification and they share some major similarities among themselves.

Complete answer:
Groups of organisms that can reproduce among themselves and produce fertile offspring are said to belong to the same species. The organisms that belong to the same species are believed to share a common pathway of evolution. Species is the taxonomic rank of an individual and the basic unit of classification. A group of species combine together to form a genus.

The process by which formation of species takes place is known as speciation. The formation of species can occur in three major ways:
1. Allopatric speciation
This speciation occurs when two species face physical barriers and are not able to reproduce because of that. Over a period of time, these animals living in different regions follow their evolutionary pathway and develop in such a way that it becomes nearly impossible for them to reproduce and produce viable offspring.

2. Parapatric speciation
This is a modified version of allopatric speciation. This happens when a group of organisms live in separate environments but are not completely isolated from one another. They may come in contact with each other and share their genes. The speciation of grass Agrostis tenuis is an example of parapatric speciation.

3. Sympatric speciation
This speciation occurs when the animals in a particular region suffer from reproductive barriers due to their feeding habits. They may prey on certain animals which may make it impossible for them to reproduce with animals from different species in the same area. Transient, resident and offshore killer whales are the perfect example of sympatric speciation.

Note
The species are separated from one another due to prezygotic and postzygotic barriers. Darwin's finches are an example of allopatric speciation. They isolated themselves and developed into different species that were not reproducible among themselves. African cichlid fishes are an example of sympatric speciation.