Video 4.4.3: Ediacaran Fauna - Prof. Phil Manning

Loading...

En provenance du cours de University of Manchester

Our Earth: Its Climate, History, and Processes

71 notes

University of Manchester

Our Earth: Its Climate, History, and Processes

71 notes

Develop a greater appreciation for how the air, water, land, and life formed and have interacted over the last 4.5 billion years.

À partir de la leçon

Life, and its Effect on Earth’s Climate System

Video 4.4.1: Welcome to The Manchester Museum - Prof. Phil Manning0:54

Video 4.4.2: Apex Chert and Stromatolites - Prof. Phil Manning 3:31

Video 4.4.3: Ediacaran Fauna - Prof. Phil Manning 5:14

Rencontrer les enseignants

Prof. David M. Schultz
Professor of Synoptic Meteorology
School of Earth, Atmospheric and Environmental Sciences
Dr Rochelle Taylor
Postdoctoral Research Associate
School of Earth, Atmospheric & Environmental Sciences
Dr Jonathan Fairman
Postdoctoral Research Associate
School of Earth, Atmospheric and Environmental Sciences

If you were looking down at Earth 600 million years ago,

you would have seen a very different planet.

A planet that was covered pole to pole in ice.

It was the ultimate snowball planet.

Could life still cling on?

It's very hard to know because there's scant evidence of life during this period.

The Ediacaran Fauna holds the evolution of life on Earth today.

Every animal we see on the planet today has its origins from this point of time.

But about 580 million years ago, these ice sheets were treated,

and we see an explosion of life.

It's life as we've never seen it before,

on a scale like we've never seen it before.

And it's exemplified by what we call the Ediacaran Fauna.

It's frustrating though,

because many of these fossils are very difficult to interpret.

Because they're soft-bodied, some of them are as large as me.

It's still very hard, though to pick apart these delicate fossil remains

which very often we only have impressions of.

It's difficult to understand what they actually were and

how they fit into the great plan of life on Earth.

The Ediacaran fossils are crucial to our understanding of life on Earth.

These were literally the answer to Darwin's dilemma.

In Origin of the Species, Darwin fought with the fact that there were no fossils

predating the later Cambrian Explosion which was rich in fossils and

hard-bodied fossils.

He did not see what was happening before this explosion of life.

But the Ediacaran gave us this pre-life explosion on Earth.

Where we see soft body fossils preserved in unique circumstances

which give us insight to life on earth when,

really, we should not be knowing anything what was going on.

For the simple reason, soft bodied animals do not preserve easily.

They are so rare.

When you're looking at the fossils from the Ediacaran times it's really

frustrating.

Some of them do actually look like animals that you might expect

to see on the planet today.

This bizarre structure here for many years was thought to be similar or

analogous to a sea pan.

Now sea pans live on the ocean floor today, and

look structurally very similar to this guy here.

This is a rangeomorph creature called Charnia from about 560 million years ago,

found within the Charnwood Forest in the UK.

When you look closely at the structure of this animal though,

key features are upside down if you want it to be a sea pan.

It would've grown in a completely different way to a sea pan as well,

making this a completely different animal.

So once we find the fossil remains and

this is a small one, these grow up to about six feet in length, two meters,

big creatures, and we often find on bedding planes covering the whole surface.

See it was a rich environment but what they actually were,

how they functioned is still open to debate.

While some of the fossils that are found within the Ediacaran Fauna are potentially

body fossils where we can see the whole animal.

Like we do here with Charnia.

Some though are trace fossils this is where it's just the impression

of where an organism has left a trace of an action, whether it be a foot print or

well, no feet at this time.

In this case it's a blob print, here we can see something like Cyclomedusa,

a jellyfish, which has landed on the sea bed.

And when it has done so, it's left an impression, and

remarkably, this fine detail has been preserved for over 560 million years.

The Ediacaran Fauna

reached it's zenith some 575 million years ago.

It's exemplified by localities such as mistaken point In Newfoundland where vast

bedding plains are covered with these beautiful fossils of the Ediacaran age.

It is not until, though, about 530 million years ago that we see

what became known as the Cambrian explosion.

These are the beautiful hard-bodied fossils that so

typify the Cambrian period.

Creatures that we all come to know and love.

However, they have their earliest origins in localities such as

the Burgess Shale and the Chengjiang fauna of China.

The Cambrian Explosion is typified by the evolution of hard parts.

For the first time, the fossil record is littered with evidence.

Evidence which is so crucial to piecing together how these animals relate

to each other, and more importantly, how they relate to life on Earth today.

Explorer notre catalogue

Rejoignez-nous gratuitement et obtenez des recommendations, des mises à jour et des offres personnalisées.

Coursera propose un accès universel à la meilleure formation au monde, en partenariat avec des universités et des organisations du plus haut niveau, pour proposer des cours en ligne.

© 2018 Coursera Inc. Tous droits réservés.

Télécharger dans l'App Store

Disponible sur Google Play