Evolution and Feathers

Fossils have shown us that one of the first known birds was part bird and part reptile. It was called archaeopteryx (sounds like "arc-ay-op-tricks"). It had scales, feathers, a bony jaw and teeth.

Later, a more recent fossil of an ancient bird was found, which had a light beak, with no teeth. This would have greatly improved flying, as it was lighter than a bony jaw and teeth. This bird was known as Confuciusornis (sounds like "Con-fushe-eew-sawn-iss").

Feathers developed from the scales of birds' lizard-like ancestors. Millions of years ago, as birds were evolving, it is possible that fluffy feathers first developed for warmth.

Perhaps some of the longer feathers gave the birds "lift" as they chased insects, leaping off the ground in hot pursuit. Or perhaps feathers helped birds to glide for longer and longer distances down from the branches.

We do not really know whether feathers first evolved for warmth or for flight, but it is true to say that today, birds use them for both warmth and flight, as well as for camouflage, protection from the sun and often as a colourful display to attract a mate.

Later, birds evolved even more changes to improve flying. They became lighter, by developing hollow bones, with a supporting criss-crossing structure inside. They also developed a breastbone, for muscle attachment so their wing muscles had something to cling on to.

When many dinosaurs became extinct about 65 million years ago, lots of birds also died out. However, many others survived and were able to multiply to take advantage of the vast areas of the Earth that had become available when other species, like flying reptiles, died out.

Today, there are about 10 thousand different species of bird. They come in many shapes and sizes, and live all over the world.