The Ultimate Atavisms Quiz

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About This Quiz

An atavism is a trait from a distant evolutionary ancestor that has reappeared in a modern-day creature, like a whale with legs. A whale with legs? Take this quiz and learn about atavistic whales and other animals.

What is an atavism?

An atavism is a trait of a distant ancestor that reappears in the modern day.

In which species do atavisms occur?

It happens with humans and other animals.

What is considered an atavism?

A good example is a whale with legs.

Is a child with a large amount of facial hair an atavism -- a reminder of our origins from the apes?

Since ape faces are hairless, this is not an atavism, unless we are descendants of werewolves.

What is the most common human atavism?

The human tail is the one you have heard about the most.

So how do atavisms happen?

One theory says that genes, such as those governing growth of a tail, are not lost in evolution but are inactive. During the development of the embryo something unknown "turns on" that gene.

What is a vestigial structure?

They are body parts that survive although they don't serve their original purpose, like an ostrich's wings, since it can't fly.

Back to the whale: How could it once have had legs?

Scientists believe that millions of years ago the ancestors of the whale walked on land. At some stage they took to the sea, probably in search of food, and since they no longer needed their legs in the water, eventually lost them.

What does Dollo's Law have to say about evolution?

It states that evolution is irreversible: Once things are lost they cannot reappear.

How does Louis Bolk's theory -- that only mammals other than humans can express atavisms -- affect the phenomenon of a human tail?

This would make the human tail a genetic fluke, but all vertebrates can grow a tail and humans are vertebrates. This fact seems to negate his theory.

Why do atavisms happen?

Scientists still don't know, despite all their research.

Can atavism be accurately attributed to other areas, such as psychology?

Atavism is used, inaccurately, to describe man's aggression as an atavism relating to his ancient past as a barbaric hunter.

What is the place of atavisms in evolution?

The truth is we simply don't know.

What do people think about when they hear "genetic information"?

They often think about controversial subjects like cloning or designer children.

Are extra fingers or toes definitely human atavisms?

At present we can only speculate until more is known.

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