Question: Have there ever been large physical changes happen during human evolution? (eg. tails, different organs ect)

Sam Geen answered on 20 Jun 2013:

People evolved from monkeys, which have tails, and we still have a tiny stub at the end of our spine that used to be a tail when we were still monkeys. All the basic organs are the roughly same, though.

The main changes that happened to humans as we evolved from apes are:
– We walk on 2 feet rather than 4 – some apes still walk on their hands and feet. This means we use our hands for other things, allowing us to make tools, point at things, do high fives, etc.
– Our brain is much larger than other apes – twice that of a gorilla or a chimpanzee. Our brains also grow very slowly compared to other animals, which gives us time to learn more as we grow up (and ask questions on I’m A Scientist :P). The Neanderthal brain was actually a bit larger than the brain of Homo Sapiens (i.e. human), although it’s still not entirely clear why they died out.
– Human men and women are also a bit more similar than other ape species, and women can get pregnant all year round and don’t give off signs that they can get pregnant, unlike other animals. We’re also less hairy (although I’m still a very hairy person…)