This bbc horizon programme is presented by our hero, sir david attenborough. Download it here.

When attenborough was just a boy, he was given a piece of amber from the baltic coast. The amber found there is at least 20 million years old; and is usually found washed up on the beach.

Amber was rightly identified by Pliny the Elder, a roman naturalist (who died in a volcano!). He put a flame to the amber and it smelled of pine resin. So he found the reason amber sometimes contained small insects; it was at some point fluid resin, flowing from trees.

Unlike fossils which are compressed over geological time and turn into rock, amber is unique in that it preserves specimens in 3 dimensions. This has been of great importance to biologists, and they’ve been able to discern a lot of new information about the way the world was millions of years ago.

For example, a single piece of amber containing multiple insects can describe the details of a small ecosystem. Some symbiotic relationships that sill exist today are revealed in amber, proving that they are very old and unchanged.

Water bugs and tadpoles have even been found in amber. This is miraculous because it means

A few pieces of hair in a piece of amber tell us that mammals were living in the tropical forests 20 million years ago, just as they do today. Hair is a mammalian characteristic, and different types of mammals have different hair structures. This hair suggests that a big cat, like a leopard, was living in those ancient forests.

Remarkably amber tells us about the rainfall so long ago. The honeypot ant has a sack on the abdomen that can fills with liquid during the dry seasons so the ants have something to drink. Today this ant only lives in Australia.

But this specimen is ancient, and was found in the Dominican Republic, in South America. This reaffirms the fact that the continents of south america and australia were connected, as one super-continent, a long long time ago.

The idea that ancient DNA can be recovered from amber is intriguing. The movies tell us that we can extract dinosaur DNA from a mosquito and use a surrogate host to bring dinosaurs back to life. But this is impossible because if any DNA could be recovered, it would be too fragmented to reassemble into an entire genome.

ancient DNA hasn’t yet been recovered, there were a few studies giving false hope, but they proved to be contaminated.

Still remarkable, amber has preserved the cell structure of ancient things. The image below is of nuclei with pieces of chromatin in the nucleus.

Very rarely, amber preserves animals much larger than insects. This lizard is so well preserved that X-Rays reveal it had a broken back, and so it couldn’t escape from the slow flow of resin.

“For me, amber remains a substance of wonder. A time machine that can show us exactly how some things looked tens of millions of years ago.” - Sir David Attenborough