Dr. Stephen Meyer

But also you have the problem, the fossil record, the major groups of organisms.

Very few, and they typically are what are called the lower taxonomic levels.

Instead, the big story is that the major groups of animals, plants and animals, but especially in the animal kingdom, arise abruptly in the fossil record.

I wrote a book about one of the big abrupt events called the Cambrian Explosion.

Explain what that is.

What is the Cambrian explosion?

Cambrian is one of the oldest periods of life as documented by the sedimentary geological record, typically dated about 520 or 530 million years ago, depending on whom you ask.

And in a narrow seam of sedimentary rock all around the world, you get roughly two-thirds of the animal body plans that have ever existed on the planet arising in that narrow window.

So suddenly.

Suddenly, abruptly.

And a body plan is a unique arrangement of body parts and tissues.

It's a unique way of putting an animal together.

So you might have some animals with hard exoskeletons like trilobites or the arthropods.

You might have some with an internal notochord or a spinal cord.

The chordates, completely different body logic.

And so you've got these different types of animals with completely different body logics arising in that narrow window of time.

And as you investigate, as paleontologists have investigated the strata beneath the Cambrian,

They do not find the transitional intermediates, the precursors that you would expect.

And we've been looking for a long, long time.

So it's very abrupt.