The major body plans that arise in the Cambrian period
exhibit considerable morphological isolation from one another (or "disparity") and then subsequent "stasis.
The Cambrian Period
ushered in the advent of shells and over time shells and exoskeletons can be fossilized, giving scientists clues into how organisms existed millions of years ago, he said.
It is one of the oldest ranges on the face of the Earth and the Cambrian period
is one of the earliest periods recorded in geology.
Harry Blackmore Whittington, 85, was awarded the 17th International Prize for Biology for his work documenting the differentiation of multicellular animals in the Cambrian period
over 500 million years ago and for other achievements.
He points out several cases of independent evolutionary development that generate nearly identical results--for example, reproduction methods in myxobacteria and slime molds, the development of keratinous beaks in birds, and the emergence of complex animal phyla at the base of the Cambrian period
In browsing through various texts, I found nothing that would convey a better idea of risk management in general than the statement by the author of an article in the October 1993 issue of National Geographic that the evolution of life forms in the Cambrian period
But for half a billion years, these cryptic organisms presumably were slowly evolving, diverging into different lineages and finally becoming big and complex enough to leave a profusion of fossils, beginning about 565 million years ago in the late Vendian geological period and extending into the Cambrian period
In the Cambrian period
of the Paleozoic era, some 500 million years ago, a burst of biological creativity took place that finds an echo in the development of many technologies.
A small creature, smaller than an inch in length, that lived about 508 million years ago was, despite its small size, likely a fierce predator on the seafloor during the middle Cambrian Period
The 3-inch-long fossil was entombed in fine dustlike particles - now preserved as fine-grain mudstone - during the Cambrian Period
520 million years ago in what today is the Yunnan province in China.
The problem was this: the base of the Cambrian period
, originally defined by Adam Sedgwick, was signified by the presence of trilobites, as well as other macroscopic fossils such as linguliform brachiopods and some strange echinoderms.
The research focused on arthropods (insects, crustaceans, arachnids and their relatives), which are the most diverse animal group in both the Cambrian period
and present day.
Erik Sperling an earth scientist at Harvard University, and colleagues say an increase in oxygen in the geologic record at the onset of the Cambrian period
allowed carnivores to evolve.
This cephalopod, whose living relatives include the octopus, squid, and cuttlefish, has roots that go back about 490 million years, into the Late Cambrian period
, and six species of nautilus in two genera still swim the oceans today.
The earliest arthropods arose in the oceans and were already high-ly developed in the early Cambrian Period
(570 million years ago) with the marine trilobites.