Life: Are We Still Evolving?

OK, this is probably going to be the last evolution post! I was only expecting to do one…

In recent years there has been one main controversy in the field. No Evolutionary Biologist I’ve ever heard of questions evolution’s existence. What is very often questioned is whether or not we are still evolving.

I’ve pointed out that every mutation is a possible evolution. But the only way this works is if that mutation is useful and allows us to be better at something. However thanks to technology, nowadays if we find something difficult, we invent something that does it for us. If the world gets colder, rather than evolving and adapting to it, we make clothes. As a result many top researchers (including Steve Jones) are arguing that Humans are no longer evolving.

Now this is where I say that they’re wrong. There is plenty of evidence for evolution in humans. It’s not always obvious, but it’s there.

For example there is a group of people who live in the Himalayas (not on top of the mountains, but higher up than most westerners would live). Up there the air is thinner and most people, if they arrived there in less than a day, would get altitude sickness. This is because they aren’t getting enough oxygen into their blood and around the body.

How does this group of people survive? They adapted and evolved. It’s only small, but it’s possible to see how the network of their blood vessels have changed. As a result they have more efficient oxygen uptake and transport, so that they can deal with the thinner air. This is a permanent trait that is heritable through the generations.

Who Thought Milk Was a Good Idea?

Want a more relatable example? How about milk. Lactose is found in cows milk, not in human milk. As many of you may have realised, we are not biologically meant to drink cows milk, and therefore not to ingest lactose. Despite the oddity of drinking from a cow, westerners have been doing it for thousands of years. Eastern people haven’t. The results? 99% of Irish people are Lactose tolerant (they can drink cows milk without getting diarrhoea). Only 5% in South East Asia can tolerate it.

OK so lactose tolerance isn’t exactly X-Men style evolution. Nor is changing the blood vessel networks. But it is still proof!

So where is evolution taking us now? A famous study in Evolution circles called the Framingham Heart Study has been used to give us some guidance. This study which catalogues several generations of families living on a single island shows that there have been changes. I must warn you these changes are monumental! They have predicted that by 2409… women will be 2 cm smaller!!!!

Note the irony.

Anyway the point I am trying to make is that we are still evolving, and in a lot of different and varied ways! Just don’t expect to see it happening right in front of your eyes.

For some more explanations and evidence visit these sites:

A synopsis of a BBC Horizon programme on the matter.

and

A specialist blog post from Why Evolution Is True.

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