Burgess Shale

Extant forms are small, only three to seven centimeters in length, slender, laterally compressed, translucent, and found in sandy sediments of coastal waters around the world.

Modern lancelets closely resemble 530 million year old Pikaia, likely one of the first chordates, fossils of which are known from the Burgess Shale.

As such, they are often studied because they hold clues within their genomes about the evolution of early vertebrates.

Let's go over their anatomy and physiology, ecology, and phylogeny.

Soft tissue, internal organs, eyes, guts, things that almost never fossilized, preserved in stunning detail half a billion years after they died.

The Burgess Shale.

The leading theory for how preservation happened is similar to what we talked about with the Ediacaran.

The organisms were buried rapidly in underwater mudslides and sealed away from oxygen before they could decay.

And unlike the Ediacaran organisms, which left impressions, some Burgess Shale fossils preserved actual body structures.

You can see what these things look like in three dimensions.

You can see what was inside them.

He was running one of the largest scientific institutions in America while simultaneously trying to describe tens of thousands of fossils unlike anything anyone had ever seen.

Its back was covered with threatening thorns, while its belly had tubular legs similar to tentacles.

The fossils discovered initially in Burgess Shale disconcerted scientists for decades, who could not determine which of their ends corresponded to the head.

Recent studies have shed light on its orientation and diet, but its evolutionary lineage remains unclear.

Scientists still debate whether it was a worm, a mollusk, or something else.

However, even these partial records show us that evolution experimented with designs in completely unknown ways for modern biology.

Marella was a tiny cambric arthropod with an unusual body plan that had ramified antennas and what seem to be legs used to swim.

This creature was so common in Burgess Shale that paleontologists assumed that it must have had great success.

However, in a relatively short period, Marella completely disappeared from the fossil record.

bits, that's tough, all

right? Yeah, but if you think about it, the epoch before the Cambrian, we have the Burgess Shale and all that soft body preservation.

So it's not like a new thing, and it's not the oldest.

A crinoid is like a sea lily.

Some of the most important fossil sites in the world are valley floor deposits, the Olduvai Gorge in the East African Rift, where Lewis and Mary Leakey discovered hominin remains that reshape the understanding of human evolution.

The Burgess Shale in British Columbia, where a valley floor mudslide 500 million years ago entombed a community of soft-bodied marine organisms.

so perfectly that their internal organs are still visible.

The La Brea Tar Pits in Los Angeles, where a valley floor seep of natural asphalt has been trapping and preserving animals for 40,000 years, from sabre-toothed cats and dire wolves to ground sloths the size of automobiles, each one walking into the sticky surface and sinking.

And this is a place of glittering skyscrapers, diverse neighbourhoods and excellent food.

One of its greatest treasures is the Royal Ontario Museum, whose world-famous collection of Burgess Shale fossils reveal an astonishing snapshot of life more than 500 million years ago during the Cambrian Explosion.

That's the moment when complex life rapidly diversified in Earth's oceans.

It was originally discovered high in the Rockies of British Columbia.