For hundreds of millions of years, trees have produced resin. In the right conditions, that resin can harden and persist in the fossil record, and when we’re lucky, it can take with it all sorts of amazing organic remains that normally escape the fossil record: rare species, evidence of ecological interaction, and even behaviors caught in progress. This episode, we talk about the amazing world of Amber.
In the news
These dinosaurs switched from quadruped to biped as they aged.
Chemical evidence of red pigment detected for the first time in fossil mice.
Sauropod walking models suggest they walked on their tip-toes.
Around one billion years old, these might be the oldest known fungi.
Many trees produce resin. This sticky substance comes in many varieties, but they all share the ability to become amber. As time passes, the resin solidifies, passing through an intermediate stage called copal before finally becoming true amber. This process can preserve the tree resin – and anything caught inside – for millions of years.
Amber is amazingly diverse. It comes in a vast variety of colors, shapes, chemical compositions, ages, and locations.
Some of the most famous amber deposits in the world include:
Lebanese amber, Early Cretaceous (~130 million years old)
Burmese amber, Late Cretaceous (~100 million years old)
Baltic amber, Eocene (~50 million years old)
Dominican amber, Miocene (~20 million years old)
But amber is found all over the world and as far back as 300 million years.
As resin flows out of a tree or drops to the ground, it has a tendency to collect things: insects, millipedes, bits of wood or fungus, and plenty more. Once inside, these inclusions dehydrate and often partially decompose, but the amber holds their 3D shape and protects them from the outside elements. In this way, amber can preserve remains that typically escape other forms of fossilization.
Inclusions in amber often represent new species, rare fossils, or even evidence of behavior and interactions between organisms. Many are truly remarkable.
Here’s a list of some amazing amber discoveries in recent news:
Hatchling lacewings in Lebanese amber
A baby Cretaceous bird in Burmese amber
A dinosaur tail in Burmese amber
An ammonite in Burmese amber
A tick on a dinosaur feather in Burmese amber
Lizards in Burmese amber
New order of insect discovered in Burmese amber
A baby snake in Burmese amber
400+ millipede species in Burmese amber
A spider caught in the act of catching a wasp in Burmese amber
Frogs in Burmese amber
Grass with a parasitic fungus in Burmese amber
Carnivorous plant in Baltic amber
Anoles in Dominican amber
Learn plenty at the World of Amber site.
A recent article about Burmese amber science: Fossils in Burmese amber offer an exquisite view of dinosaur times—and an ethical minefield
For more technical info (and some photos!), look up these papers:
Poinar 2003. Insects in Amber
Martínez-Delclòs et al 2004. Taphonomy of insects in carbonates and amber
Vávra 2008. The Chemistry of Amber – Facts, Findings and Opinions
Oh, and about DNA:
Amber does not appear to preserve DNA. Paper and news article.
Technical review of claims of ancient DNA in amber
UPDATE: One major issue we did not discuss in this episode is the ethical dilemma surrounding amber. Here is a recent post by Mark Witton that offers a summary and lots of links about issues with Burmese Amber.
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