These articles explore evolution - the changes seen in the inherited traits of a population from one generation to the next. Evolution is one of the great mysteries of biology, since it is a slow process and difficult to study.
Think your job is hard? Biological anthropologists use tools from practically all walks of science to understand the differences within and between human populations. Investigating the environmental and hereditary bases of diversity isn't easy.
We're used to taking the phrase "survival of the fittest" to mean it's an "every man for himself" world. But some animals (like worker bees) sacrifice themselves to ensure their species lives on. Why would they do this?