CLIMATE SHAPES SPECIES

Gradual changes in a population that lives ina region with environmental shifts give rise to new species

- RAJEEV PATNAIK

CHANGES IN water availability, rainfall, temperature and humidity, either globally or locally, can shape evolution. When we look at the origin and evolution of humans, many climatic changes have occurred over millions of years. Six million years ago, human ancestors separated from a branch comprising of chimpanzees and gorillas.

This new branch became known as hominin, which includes humans, extinct humans, and our immediate ancestors that could walk upright. This change corresponded to climatic changes.

We have evolved from unicellular organisms, thanks to climatic conditions. If conditions had not changed, perhaps there would have only been microbes in the ocean. If you look at life as a tree, the branches kept changing until humans reached a particular branch. The bacteria that did not change perhaps lived in an environment that was constant, so they stayed the same.

If there are gradual changes in a population, and a part of it lives in a region witnessing environmental changes, it gives rise to new species.

There are two kinds of changes: genetic and phenotypic (observable, physical changes). Even now, genetic changes keep happening automatically. But they do not necessarily translate to changes in the human body or physical appearance. Physical changes occur only if there is a change in our diet or locomotion. For example, if a species ingests tough food, it will develop a heavy jaw. If it evolves to consume softer food, a heavy jaw is useless, and it recedes. Simply put, if the climate does not change, humans or any living being will not evolve. When climatic conditions change, they induce changes in vegetation, and that has shaped human evolution.