Quotes About Cambrian

Cambrian animals were not particularly large at first, but they were plentiful and innovative. Jaws appeared. Eyes appeared. Nature began experimenting with weaponry.

Now, traveling about twice as far back again in Earth time, back to 542 million years ago, we encounter another sudden massive wave of extinction instigated by runaway biology: The Cambrian substrate revolution, when the texture and chemistry of the seafloor (at that time, the entire habitable surface of the planet) was rapidly remade by a spurt of biological innovation that caused both mass death and fantastic new evolutionary opportunity. This

All nucleated organisms generate excess calcium as a waste product. Since at least the Cambrian times, organisms have accumulated those calcium reserves, and put them to good use: building shells, teeth, skeletons. Your ability to walk upright is due to evolution's knack for recycling its toxic waste.

remote in time from us the Cambrian outburst was. If you could fly backwards into the past at the rate of one year per second, it would take you about half an hour to reach the time of Christ, and a little over three weeks to get back to the beginnings of human life. But it would take you twenty years to reach the dawn of the Cambrian period. It was, in other words, an extremely long time ago and the world was a very different

More than 500 million years ago, vision became the primary driving force of evolution's 'big bang', the Cambrian Explosion, which resulted in explosive speciation of the animal kingdom. 500 million years later, AI technology is at the verge of changing the landscape of how humans live, work, communicate,and shape our environment.

If Darwin is right, Agassiz argued, then we should find not just one or a few missing links, but innumerable links shading almost imperceptibly from alleged ancestors to presumed descendants. Geologists, however, had found no such myriad of transitional forms leading to the Cambrian fauna. Instead, the stratigraphic column seemed to document the abrupt appearance of the earliest animals. Agassiz

Geologists, however, had found no such myriad of transitional forms leading to the Cambrian fauna. Instead, the stratigraphic column seemed to document the abrupt appearance of the earliest animals.

Geologists, however, had found no such myriad of transitional forms leading to the Cambrian fauna. Instead, the stratigraphic column seemed to document the abrupt appearance of the earliest animals. Agassiz thought the evidence of abrupt appearance, and the absence of ancestral forms in the Precambrian, refuted Darwin's theory.

Yet we would not expect the neo-Darwinian mechanism of natural selection acting on random genetic mutations to produce the top-down pattern that we observe in the history of life following the Cambrian explosion.

The question that Darwin's early critics posed was this: How could he reconcile his theory of gradual evolution with a fossil record so discontinuous that it had given rise to the names of the major distinct periods of geological time, particularly when the first animal forms seemed to spring into existence during the Cambrian as if from nowhere?

there is still a mystery to speculate about: Why and how did many animals begin to have hard parts—skeletons of sorts—with apparent suddenness around the beginning of the Cambrian?"24

The relative suddenness of the Cambrian explosion, even on the earlier measure of its duration, had already raised serious questions about the adequacy of the neo-Darwinian mechanism; consequently, it had also raised questions about whether a Darwinian understanding of the history of life could be reconciled with the Cambrian and Precambrian fossil record.

In any case, the discovery in China of chordates, and other previously undiscovered phyla in the Cambrian, only accentuates the puzzling top-down pattern of appearance that other Cambrian discoveries had previously established.

The term "Cambrian explosion" was to become common coin, because Walcott's site suggested the geologically abrupt appearance of a menagerie of animals as various as any found in the gaudiest science fiction. During this explosion of fauna, representatives of about twenty of the roughly twenty-seven total phyla present in the known fossil record made their first appearance on earth (see Fig. 2.5).

Oxford biologists Alan Cooper and Richard Fortey depict the Ediacaran fauna as lying on a line of descent separate from the Cambrian animals rather than being ancestral to them.23

A PUZZLING PATTERN Over the years, as paleontologists have reflected on the overall pattern of the Precambrian–Cambrian fossil record in light of Walcott's discoveries, they too have noted several features of the Cambrian explosion that are unexpected from a Darwinian point of view11 in particular: (1) the sudden appearance of Cambrian animal forms; (2)

Despite the scope of his synthesis, there was one set of facts that troubled Darwin—something he conceded his theory couldn't adequately explain, at least at present. Darwin was puzzled by a pattern in the fossil record that seemed to document the geologically sudden appearance of animal life in a remote period of geologic history, a period that at first was commonly called the Silurian, but later came to be known as the Cambrian.

Agassiz concluded that the fossil record, particularly the record of the explosion of Cambrian animal life, posed an insuperable difficulty for Darwin's theory

FIGURE 2.8 According to Darwinian theory, the strata beneath the Cambrian rocks should evidence many ancestral and intermediate forms. Such forms have not been found for the vast majority of animal phyla. These anticipated but missing forms are represented by the gray circles. Lines and dark circles depict fossilized representatives of phyla that have been found.

600 million years ago, the monopolizing grip of the algae was broken and an enormous proliferation of new lifeforms emerged, an event called the Cambrian explosion. Life had arisen almost immediately after the origin of the Earth, which suggests that life may be an inevitable chemical process on an Earth-like planet.

The clam had shown up 200 million years before the action really began. Virtually all the phyla that have crawled, walked, flown, or swum during the modern era arose roughly 520 million years ago in a blink of geologic time so brief it's called the "Cambrian explosion.

a lot of evolution has gone over the dam since 3.5 billion B.C. What, if anything, has happened to the global brain since then? The story is a strange one. Paleontological dogma has it that virtually nothing of significance occurred again until the Cambrian explosion roughly 535 million years ago.

If all these considerations are correct, then the appearance of eyes really could have ignited the Cambrian explosion. And if that's the case, then the evolution of the eye must certainly number among the most dramatic and important events in the whole history of life on earth.

Cambrian period, some 550 million years ago, soon after a big global rise in atmospheric oxygen.