Darwin theory: What’s it all about?

Charles Darwin: 1809 - 1882 The father of evolution

Sideline Science…

Evolving means developing

features or characteristics that make us better adapted to the environment around us.

According to Darwinian theory, you are described as ‘fit’ if you can:

1 – Adapt to your environment, The theory of evolution e.g. anemones produce mucus during low tide to reduce water Many biologists accept the fact that the life living around loss. us, and we as the human race, are here as we are because of the process of evolution. Evolution determines the way life develops in all forms of life, from tiny bacteria to plants and animals.

‘You’re fit!’ – In a genetics kind of way!

Evolution works through several mechanisms. One of the most important is natural selection. Charles Darwin 2 – Compete for resources in (pictured) proposed that evolution works on the theory of limited supply, e.g. competition survival of the fittest. This means that individuals in a between hermit crabs for shells. population, or community, are more likely to survive if they are fit – in a genetics sense.

Every organism is slightly different to every other, even those of the same species. Some of these differences in characteristics help an individual do better, and produce more offspring. 3 – If you are a good hunter / If the offspring inherit the successful characteristic from can avoid being eaten! e.g. their parent they too will do better, and have more camouflaging like this plaice. offspring. Gradually, over generations, the characteristic will spread through the population. Hey presto – you have a population of individuals that are well adapted to their environment! It’s all about the genes

When Darwin developed his theory, he did not know how characteristics were passed from parents to offspring. We now know that the variations in characteristics are caused by differences in genes (figure 1) – but not the kind you wear!

A Gene

Figure 1 – A strand of DNA, indicating a gene which leads to a characteristic to develop

Genes are essentially a piece of DNA, which hold information that enables characteristics to develop. Characteristics develop because of useful mutations in our DNA. Over time for example, anemones on the rocky shore have developed the mucus secretion gene, which enables them to reduce water loss during low tide.

The take home message…

Useful mutations of our DNA helps us all to survive in the environment around us.

Did you know?

Differences in a population can be caused by environmental and inherited variation