British Sign Language Glossaries of Curriculum Terms

BSL Environmental Science Glossary - Speciation definition

Definition: Speciation is a process that allows new species – animals and plants – to develop. Members of the population may move to different areas and become geographically isolated. Over the years, they will follow a different evolutionary path, and the gene pool will change. They will look different from each other - for example, peppered moths.

Years ago, before the industrial revolution in the UK, most peppered moths were pale-coloured. They were camouflaged against the pale birch trees where they rest on. Black peppered moths with a mutant black colouring were quickly spotted and eaten by birds. This gave the white moths an advantage, and they were more likely to survive.

During the industrial revolution, pollution in industrial areas covered the birch tree bark with soot. The mutant black moths were now camouflaged and more challenging to see, but the white variety became more vulnerable to birds. This gave the black variety an advantage, making them more likely to survive. Over time, the black peppered moths became far more common in urban areas than the pale variety. The dark variety had always existed but was the best-suited variant when the environment changed.

However, nowadays, with cleaner air, they are easily spotted on the tree bark.