In a universal sense evolution is simply change

In the biological sense, evolution is the change in characteristics from one organism to the next. A species is considered to be evolutionary when different genetic characteristics are intergeneration-ably inheritable. Thus, evolution cannot occur over one organism’s lifetime as it is the result of change though many subsequent generations.

There are several key players in the theory of evolution, the big two being Jean Baptiste Lamarck and Charles Darwin. Lamarck was the first person to describe how a population can change and evolve. Lamarck studied Buffon’s work, and a large proportion of his studies were devoted to classifying plants and invertebrates. He believed that the only way similarities between different species could occur is if species were evolving. Lamarck thought that species evolved because of their struggle to survive.

Lamarck Darwin





Aspects of a species that were depended on became dominant and improved, and parts which served little purpose were weakened and diminished.

He called these - acquired characteristics.

Darwin’s theory was different. He spend are large proportion of time studying distribution of plant and animal species. Darwin believed the “survival of the fittest” theory; that the species better suited to their environment would survive and the other species would die out. This would eventually result in the overriding dominance of one species.

Natural selection suggests that a species with favourable characteristics is more likely to survive, exist and reproduce in their chosen habitat, conversely those with unfavourable characteristics are less likely to survive. If an environment stays constant the then variation between all the organisms in a species will decline and all organisms will eventually look near identical. This is of course very unlikely as environments are usually affected by us humans as well as inconsistent weather and climate changes.

There are three primary sources of genetic variation; Mutations are changes in the DNA. A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations. Gene flow is any movement of genes from one population to another and is an important source of genetic variation. Sex can introduce new gene combinations into a population. This genetic shuffling is another important source of genetic variation.

Adaptation is the evolutionary process where a population becomes better suited to its habitat. There are three types of adaptation; physical, physiological and behavioural.

Physical adaptation is the change in an organism’s physical characteristics in order to fit in better with its environment, perhaps better known as camouflage.

Physiological adaptation, where organisms respond to environmental change in order to survive or live easier. e.g developing gills to live in water easier.

Behavioural adaptation is when an organism changes it’s behaviours in order to survive. Preditation is where a species preys on another to survive. The species would need to adapt in order to survive otherwise the most camouflaged organism or the least likely to be preyed on will become dominant.





This has been a brief biology introduction on the topics of evolution, genetic variation and adaptation.





Thanks for reading