Intermediate
Why Humans Don't Have Tails: Scientists Discover Gene Change
February 28th, 2024
A long time ago, people's ancient family members had tails, like many animals today. But about 20 to 25 million years ago, when our family tree split from monkeys, we lost our tails. Scientists have always wondered why this happened.
Now, some doctors who study genes think they found one answer. They found a small change in the genes that might have made tails go away. These doctors looked at the genes of apes and monkeys and saw something different. Then they tried an experiment with mice by changing a tiny part of their genes. The baby mice were born without tails!
This change might not be the only reason we don't have tails, and doctors are not sure if not having a tail helped those animals live better. But some people think maybe not having a tail helped them move in a new way, and later, it helped people stand and walk with their two feet.
Some apes today still live in trees without tails. They move by swinging from branch to branch instead of running on top of the branches with tails for balance.
But we can't know for sure why no tails are better unless we could go back in time. The doctors who did this study got help from a special group that likes to teach people about science. They want us to understand how living things change over time.
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💭 Discussion Questions
1
. Why did people from a long time ago not have tails?2
. What did doctors find out about the genes of apes and monkeys?3
. How do some apes move in the trees without having tails?📖 Vocabulary
🌐 Cultural context
The article discusses human evolution, a science topic. It is based on research about genetic changes that led humans to lose their tails, linking it to walking upright. Evolution is a subject studied worldwide in biology classes.
🧠 Further reading
Bipedalism
Some animals and robots move by using their two back legs. We call these kinds of animals and robots 'bipeds', which means 'two feet'. There are different ways bipeds move, like walking, running, or hopping.
A lot of animals always walk on two legs. Some dinosaurs long ago used to do this, and birds today are like those dinosaurs because they also walk on two legs. Some animals like kangaroos, tiny kangaroo rats, and even some types of monkeys and apes walk on two legs too, but not all animals do this all the time.
Some animals only walk on two legs for a short time. For example, some lizards run on two legs to get away from danger. Monkeys and bears might stand on two legs to get food or look around. Some monkeys that live in trees walk on two legs when they come down to the ground. Animals also stand on their back legs when they fight, look for a mate or want to look at something far away.
The word we use for animals that walk on two legs comes from two Latin words that mean 'two' and 'foot'. Walking on two legs can be very helpful for animals because it lets them see better and do things like reach for food or look out for danger.
Evolution
Evolution is how living things change over time. It happens when certain traits become more or less common in a group of living things. There are two men, Charles Darwin and Alfred Russel Wallace, who thought of the idea that nature selects the best traits for living. This idea helps to explain why living things look and act as they do to survive in their homes.
A long time ago, Darwin wrote a book that talks about how nature chooses the best traits. We know this happens because: more babies are born than can live, living things are different from each other, some are better at surviving, and parents pass on their traits to their children. So, over time, the children that are better at living in their home will grow up and have babies too.
Later, people added more information about how traits are passed down through DNA. This added to Darwin’s ideas to create what we know today about evolution. It’s amazing to think that every living thing on Earth, even us, came from one common family that lived billions of years ago. We can see how living things changed by looking at fossils and other signs from a long time ago.
William Charles Osman Hill
William Charles Osman Hill was a very important person who knew a lot about animals called primates, which include monkeys, apes, and humans. He was born in the United Kingdom on July 13, 1901. He loved learning and he went to a school called King Edward VI Camp Hill School for Boys. Then, he went to the University of Birmingham where he learned about medicine and animals.
He did very well in school and won some prizes. After he finished school, he became a teacher at the same university. He taught about animal bodies. In 1930, Mr. Hill moved to a place called Sri Lanka and became a teacher at the Ceylon Medical College. He studied the people and animals of Sri Lanka, and he had his own collection of different animals to learn more about them.
Mr. Hill wrote many books and articles – 248 in total! He is very famous for creating a big set of books about primates. He worked very hard on these books, and they had pictures drawn by his wife, Yvonne. They helped people understand a lot about primates. When Mr. Hill died in 1975, he left behind a large number of animal specimens which are now kept by a place called the Royal College of Surgeons of England. These specimens help other people learn about primates too.