Human evolution and how science works

I am just finishing up a fairly in-depth look at the theory of evolution with my Grade 12 students. Towards the end we study human evolution, which offers a great opportunity to illustrate how science changes as our knowledge develops and new facts become available. Each year, before I teach this topic, I have a quick scan of a website such as Science Daily to see what the latest findings are in the field of paleoanthropology. 

Two recent publications highlight the rapidly-changing nature of our current thinking in relation to human evolution.

Image via Pixabay

The first article, published in the journal Nature and summarised here, puts back the arrival of hominins in east Asia several hundred thousand years, from 1.8 million to 2.1 million years ago. Hominins are the evolutionary line that led to us, Homo sapiens, as well as earlier Homo species and members of the genus Australopithecus. The article clearly illustrates to students how, as new evidence becomes available, our scientific knowledge can be updated accordingly. 


The second article, published here in the open access journal Trends in Ecology & Evolution, claims that recent evidence no longer supports the notion that H. sapiens evolved in a localised area in east Africa, and instead shows a more complex, geographically-dispersed evolutionary history throughout Africa. The authors conclude that this changing view, of a more 'mosaic-like' evolution of recent human ancestors in a multi-regional pattern across Africa, means that earlier hypotheses and assumptions need to be adjusted to take these new facts into account. The article also highlights knowledge gaps and areas in which future research should focus. This can be used to reinforce with students the point that good science often asks as many new questions as it answers existing ones. 

By using examples like this from the field of paleoanthropology, students get to see both the latest research and the ever-changing nature of science.