The Weird Youth of the Animal Kingdom (Slide Show)

Paleontologists have found traces of animal life dating back at least 635 million years. Those earliest animals may have been like today’s sponges, rooted to the sea floor and filtering food particles from the water. Over the next 100 million years or so, new kinds of animals emerged. Some were recognizable members of living groups of animals, while others were so bizarre that paleontologists suspect they belonged to long-extinct lineages. And then, around 520 million years ago, the fossil record of animals starts to roar like a firehose switched from a trickle to full blast. Many of the oldest known members of living animal groups–including our own–appear during the Cambrian Period. But the Cambrian fossil record is also rife with forms only distantly related to animals on Earth today, some of which were so weird that the sight of a reconstruction of the creatures made scientists burst out laughing.

Many people have become familiar with this period of evolution through Steven Jay Gould’s 1989 influential book, Wonderful Life. In the 24 years since then, scientists have learned a lot more about the Cambrian. Two of the leading experts on the period, Doug Erwin of the Smithsonian Institution and James Valentine of Berkeley have collaborated on a new book, The Cambrian Explosion: The Construction of Animal Biodiversity, in which they synthesize evidence, both old and new, about this exceptional chapter in animal evolution.

The so-called Cambrian Explosion probably had many fuses. Erwin and Valentine explain how the Earth was undergoing drastic changes in the millions of years leading up to the flowering of the animal kingdom, with global ice ages and a burst of oxygen flooding the oceans. The stage was set for big, active creatures to evolve. As predators emerged, their prey became better defended with spikes and shields; the predators in turn became even deadlier. The animals changed their environment–burrowing animals, for example, pierced the sea floor with countless tunnels. As the environment changed, new kinds of animals evolved that could occupy new niches. The animal kingdom became both physically and ecologically complex.

But the diversity of the Cambrian had another source: the DNA of the animals themselves. Animals evolved genetic programs for turning a single egg into a complex body. These programs turned out to be supremely evolvable–with relatively minor mutations, they could give rise to new forms.

The book is also accompanied by some remarkable paintings by Quade Paul. I’ve reproduced some of them here as a slide show, and below.

Myllokunmingia may be the oldest known vertebrate, with a skull made of cartilage and other hallmarks of vertebrates (like us). Copyright Quade Paul
Myllokunmingia may be the oldest known vertebrate, with a skull made of cartilage and other hallmarks of vertebrates (like us). Copyright Quade Paul
Herpetograster may have belonged to the same lineage that produced to living starfish and acorn worms
Herpetogaster may be related to living starfish and acorn worms
Banffia is baffling; it's not clear yet what its closest living relatives are. Copyright Quade Paul
Banffia is baffling; it’s not clear yet what its closest living relatives are. Copyright Quade Paul
Diania had spiked, segmented legs that show some similarities to those of insects and other arthropods. Some scientists see that as a sign of close kinship. Copyright Quade Paul
Diania had spiked, segmented legs that show some similarities to those of insects and other arthropods. Some scientists see that as a sign of close kinship. Copyright Quade Paul
Hurdia was a primitive cousin of insects and other arthropods. Copyright Quade Paul
Hurdia was a primitive cousin of insects and other arthropods. Copyright Quade Paul
Anomalocaris was a giant of the Cambrian, reaching over a meter long. Copyright Quade Paul
Anomalocaris was a giant of the Cambrian, reaching over a meter long. Copyright Quade Paul
Fuxianhuia is a close relative of living arthropods such as insects. Copyright Quade Paul
Fuxianhuia is a close relative of living arthropods such as insects. Copyright Quade Paul
Odontogriphus had a circular mouth ringed with teeth. Copyright Quade Paul
Odontogriphus had a circular mouth ringed with teeth. Copyright Quade Paul
Wiwaxia may have been related to today's mollusks. Copyright Quade Paul
Wiwaxia may have been related to today’s mollusks. Copyright Quade Paul
Maotianoascus and Ctenorhabdotus were early relatives of today's comb jellies. Copyright Quade Paul
Maotianoascus and Ctenorhabdotus were early relatives of today’s jellyfish. Copyright Quade Paul
Orthozanclus, a relative of mollusks. Copyright Quade Paul
Orthozanclus, a relative of mollusks. Copyright Quade Paul
Pikaia was a relative of vertebrates. Copyright Quade Paul
Pikaia was a relative of vertebrates. Copyright Quade Paul
Pikaia description
Opabinia had five eyes and a single appendage extending from its head. Copyright Quade Paul
Opabinia had five eyes and a single appendage extending from its head. Copyright Quade Paul

All the pictures in this post are copyright 2013 Quade Paul.

(Full disclosure: The publisher of this book, Roberts & Company, also publishes my textbooks, which include some illustrations by Paul.)

33 thoughts on “The Weird Youth of the Animal Kingdom (Slide Show)

  1. The Cambrian was a wonderful time of experimentation in the history of life. We are fortunate that scavengers were not the first animals or we might not have had these wonderful and delicate creatures preserved all over the world.

    Even here in Utah we preserved Cambrian soft body animals in our West Desert at four different levels.

  2. Of course, they’re from the Cambrian period, the time when Nature had just begun experimenting on the first life forms, trying out some weird evolutionary mutations and stuff like that to see what works, producing these weird little critters of all kinds of queer shapes and forms. They’re really supposed to be strange/weird. 🙂

  3. I wonder, was the discovery of these bizarre critters an influence on the young H. P. Lovecraft? Because some of those things are pretty disturbing.

  4. Regarding the usual comments that these are “experiments” of evolution: in that case every single species ever, including all alive today, are experiments. The fact that we find fossils of these animals means that they were highly successful (ie. well adapted) in their time. The fact that they died (in some cases major lineages) out is irrelevant in assessing how successful they were.
    Regarding the pictures: these are arguable the best I’ve ever seen of these.

  5. It’s too bad that so many creationists still think that the Cambrian “Explosion” was an instantaneous event rather than taking tens of millions of years.

    The Dishonesty Institute’s Stephen Meyer has a book coming out about this in June, “Darwin’s Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design”. We await with bated breath how many creationist tropes will appear in this book. In the meantime, I’m sure we all wish Erwin and Valentine great success with their new book – even if it is $60…I think I will wait for the Kindle edition.

  6. These are incredible, I can see how our modern-day creatures evolved from some of these. The Hurdia on the other hand is definitely a Pokemon.

  7. Actually, as fascinating and odd looking as these early creatures are, we have thousands that are just as strange and fascinating today. Watch some of the videos about the behavior of cuttlefish and the fauna living around the undersea volcanic vents. If you have done any diving, you will see fascinating sea slugs and the wierdest looking sea cucumbers.

  8. Is part of the novelty a trick of perspective? The mighty limbs of an oak tree, separately branching and supporting further multiple branchings, were at one time as close and as similar as two new twigs on the end of a minor branch.

  9. The skin texture you gave Myllokunmingia looks like fish scales. If you meant to do this, that’s inaccurate. Fish scales are bone plates in the skin, and M. had no bone at all. Hagfish and lampreys lack scales, too!

  10. The world keeps evolving…yet we have christians that say it shouldn’t be taught in school. That’s another debate, just shows how humans haven’t evolved enough yet with intelligence. But my true comment is, if evolving means change, it’s because the environment changes around us I would hypothesize, but what if our surroundings became a baseline constant, what would the worlds purest form look like, where it didn’t have to evolve any longer…? I challenge evolutionary artists to that one!

  11. Something that has always fascinated me is how forms seem to repeat themselves in the physical world. Starting with the atom, we have a nucleus, with electrons orbiting around it. Then we have our solar system where our planets orbit around the sun (a star). Then we have our spiral galaxies with billions of stars orbiting around some central nucleus (perhaps a black hole). And now, we know that our spiral galaxy, along with millions of other galaxies, is orbiting around some other nucleus. For all we know, this is just one of millions of other groups, evolving around some even greater central nucleus. The mind boggles.

  12. Fascinating, and (mostly) good comments too!

    @Michael Handley: Other species are the environment of a species too, it is unlikely that a diversified biosphere as ours would settle into stasis even if the rest of a species environment would. The best approximation would be early Earth, so prokaryotes would be forms compatible with stasis.

    @June Ariola: That is pattern search, and it is futile here as everywhere else.

    – There is in fact no correspondence between atoms and planets. The simplified atom model is not anything near the actual atom with its electron clouds, where there is a finite likelihood for electrons to appear _within_ the nucleus (except for the lowest energy spherical electron state).

    – Stars in galaxies orbits overall (not counting clusters) a common center by way of the virial theorem. There does not need to be anything particular in the center, and in fact it seems our own Milky Way bar is not exactly centered on the mass center of its dark matter (the most massive component).

    – Galaxy clusters emerges out of dark matter filaments from primordial fluctuations in the inflationary standard cosmology. It is too complicated trajectories to remind of the virial theorem as applied to an isolated galaxy. The filaments doesn’t merit the idea of nucleus, rather they look like embeddings of the visible matter.

    1. Torbjorn, thank you for your wonderful explanation of pattern search.

      I also find it interesting that many believe there cannot be life on a planet such as Venus, with its seemingly harsh atmosphere. There are other types of life forms here on our very planet that live in harsh environments… such as the bacteria living in the highly acid environment of the stomach and the life around the boiling environment of the volcanic vents at the bottom of the sea. Creatures live in the deep parts of the ocean where the pressure is so strong it would crush most earthly life forms. They find tiny worms living in the frozen ice of glaciers. I think that life forms will appear in many of the places we now think unlikely.

  13. Those of you fixated on the Cambrian must note the Ediacarian — the period immediately predating the Cambrian. Some of these shapes shown here are from more than 600 million years ago.

  14. @ Paul. I am a creationist. I also know that the Earth not the universe was created in 6 spans of our supreme beings division of time. The universe took much longer. This being said I think scientist today have aged the universe about 4.5-5 billion years younger than it really is. The Universe was around 18.25 billion years old at the time of Muhammad is what the Qu’ran says, the math of how I got this number is a different topic. Though anyone interested in the math and the religious references to it, just ask and I will provide you a link. This being said, the idea that these “experiments” in evolution are not so unthinkable. The “day” in which life was created would have been about 1.8 million years as we measure time. However where this 1.8 million year time line started in the process of the creation of the universe is not clear to me, though I am self taught and by no means an expert; I would guess at the time length from creation of the planet to the start of life. When we take into account the Book of Enoch it seems foolish that a creationist would not believe in evolution.

  15. Creationism can in some cases hold quite an intelligent argument but the second any established religion is introduced into the equation it becomes pure idiocy. The close-mindedness, subjective perception and minuscule cognitive grasp of reality shown by every single known religion is proof enough that they are false. The idea that there are beings, possibly even a being, who laid the foundation for life on Earth is completely possible, but it would look nothing like our “God”, it would have to be so intelligent beyond our comprehension that our sentience would hold the equivalent complexity of an ant to ourselves. This being would not be a god, it would simply be more advanced. Who’s to say that some day we won’t plant the proper materials for life, and jump-start it on another planet?

  16. The phenomenon of ‘creationists’ is truly sad, as they are so often opposed to most elements of science. Beliefs have consequences, & those consequences can be universally lethal. The most recent example in human history would be HIV/AIDS, which is regarded by many of the religious right as the punishment of an angry deity.Thus, during the early years of the epidemic; they fought vigorously & successfully; against the use of any public funds for HIV research. The subsequent delay in the development of effective treatment options denied thousands even a fighting chance at survival. The consequences of religious beliefs do not spare children, either. In some christian schools in British Columbia, there’s been an outbreak of measles, as their parents refuse to have their children vaccinated based on religious beliefs. This naturally places others in the communities at risk. That makes their beliefs a health hazard.

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