Speciation

Introduction

Speciation is the process by which new biological species are formed.
It occurs when populations of organisms become distinct and reproductively isolated from one another, preventing interbreeding.

Speciation is a result of several factors:

a. Isolation: Populations become separated, either geographically or ecologically, preventing gene flow between them.

b. Mutation: Genetic changes (mutations) occur over time, leading to genetic differences within isolated populations.

c. Selection: Natural selection in different environments favours different adaptations, leading to the development of distinct characteristics.

Speciation diagram

Allopatric speciation occurs when new species arise due to the geographical isolation of populations.
Geographical barriers, such as rivers or mountain ranges, can isolate populations of animals and plants.
Over time, genetic differences accumulate in these isolated populations, leading to the formation of distinct species.
The movement of land masses (continental drift) millions of years ago also played a role in geographical isolation.

Sympatric speciation is the formation of new species despite occupying the same geographical area.
It can occur through different mechanisms:
- Ecological Barriers: Populations may be isolated within the same region due to occupying different habitats or breeding areas, having different pH or salinity preferences, etc.
- Behavioural Barriers: Complex mating rituals, timing, locations, or mating dances may create barriers to reproduction within a population that is not geographically separated.

Speciation Diagram

As time passes and genetic differences accumulate, populations may become so distinct that they are unable to interbreed successfully.
When two populations that have undergone speciation attempts to mate, they may produce offspring that are either sterile or have reduced fitness.
These distinct populations are considered separate species.

bookmarkSummary

Speciation is the process of forming new biological species.
It occurs due to isolation, mutation, and selection.
Allopatric speciation results from geographical isolation, while sympatric speciation occurs within the same geographic area through ecological or behavioural barriers.
Over time, distinct populations become reproductively isolated and are classified as separate species.