Last modified on April 9th, 2020 at 12:46 pm

What Is Evolution – The Theory Explained

Evolution is the name of the process that explains how species of living things change over time.

The theory of evolution supports the idea that all life on Earth is related to one another, originating from common ancestry. From the primordial soup that formed those first life giving molecules, life has progressed and evolved to produce all that exists today. Through the process of evolution, simple living organisms, through gradual change, become complex and diverse.

Though technically a theory, the theory of evolution is supported by a huge body of evidence and is widely accepted by the scientific community. Even the Catholic Church has recognized its significance in recent times.

Natural Selection

Charles Darwin’s theory of evolution is driven by a phenomenon known as “natural selection”.  The theory describes how physical variations in a species as a result of their genetics, are the determining factor in its evolution.

Certain individuals in a species may have characteristics that give them a survival advantage in their environment. As a result, they are most likely to survive to pass on their genes to their offspring. The individuals that lack any survival advantage and are less adapted to their environment, are less likely to survive and pass on their genes.

Over time the genes that code for that advantageous characteristic become the dominant form in that species. When this occurs, the species is said to have evolved.

Our Evolutionary Past

Fossil records are probably the clearest signs of evolution to be found in nature. Through fossil records, biologists can track the chain of evolutionary events that have shaped life on Earth. A detailed timeline has been constructed that chronicles the transition of life from the oceans, to the land and the skies.

Life began in our oceans, first as simple molecules that evolved to form complex multi cellular animals. In order to survive on land, these creatures had to undergo a lot of changes. The normally aquatic animals encountered a host of new challenges: they had to counter the drying effect of the sun, the gravitational effect of the planet and develop an entirely new breathing system just to name a few. The tetrapods (four legged animals) were the first class of animal to overcome these challenges and they went on to successfully colonize the land. The tetrapods gave rise to all land species, current and ancient, including the dinosaurs, birds, amphibians, mammals and reptiles.


Evolution In Nature

As all life on Earth came from the same origin, another way of observing evolution is to find the links between species. Many animals share physical traits and through taxonomy we can group them accordingly. Through analysis of these groups we can track the development of common traits in order to discover common ancestry, a process known as phylogeny.

Humans are believed to have descended from apes, a lineage we share with the likes of chimpanzees and bonobos. If we trace back far enough we can identify a species that diverged to form both homosapiens and chimpanzees. At some point that species must have been split into two distinct groups that became isolated from one another. Over time, each population developed different variations and through the process of evolution, progressed to become so different from each other, they became new species.

homo erectus skull

Signs of evolution can also be found in species that have a unique physical trait. The giraffe is one such species with a unique physical trait, making it a classic example of natural selection. The giraffes with the longest necks were able to reach the leaves higher on the trees and were less likely to starve as a result. Over time, the giraffes with shorter necks died off due to starvation and so the giraffes with long necks became the dominant type.

Evolution In Action

The process of evolution is a slow one; it can take centuries to observe noticeable changes.

However if we reduce our scale and watch the smallest organisms at work, we can actually see evolution in action. Evolution at its fastest can be seen in microorganisms such as bacteria.

We find bacteria capable of surviving the most extreme temperatures and pressures found on Earth. Bacteria are constantly evolving, adapting to their environment and unfortunately for us, developing resistances to many antibiotics.

In the video below you can actually observe evolution in action as the bacteria over time, develop the means to grow in ever increasing antibiotic concentrations.

The Future Of Evolution

Human society has had a huge impact on the evolution of species all over the planet and we will continue to shape life around us. We ourselves have a world of opportunities for our own evolution. As the world continues to shrink and populations from different ethnicities continue to interbreed, the human species in all its diversity makes a slow transition to uniformity.

Dan Jones

Dan Jones is a world traveller, aspiring yogi and a research scientist. You can find more from him on his holistic lifestyle blog at