Source: http://ircamera.as.arizona.edu/NatSci102/NatSci102/lectures/lifeadvanced.htm

Plants and a few forms of  simple animals began to evolve. from Rick Miller,  http://www-rohan.sdsu.edu/~rhmiller/fossil_record/ediac4.htmSome fossils from this era are below (with centimeter rules for scale), from G. M. Narbonne, Queens Univ., Newfoundland, Canada Fossils from Mistaken Point, Newfoundland

These plants and animals were built by making a series of slightly modified copies of a small number of biological designs. This type of construction was another huge advance, and remains the way plants and animals develop today. The development process is controlled by biological "switches" that regulate the way large numbers of cells grow and organize themselves. As a result, evolution could proceed - a change in a switch is sufficient to produce a coherent, new form of organism.

Still, not much happened, until just over 500 million years ago there was a sudden appearance of complex multi-cellular plants and animals in the warm seas of the Cambrian era. The rapid increase in the varieties of life entering the Cambrian era is called the "Cambrian Explosion" - shown to the left as the number of biological "orders" in the fossil record, going from about 610 million to about 525 million years before the present (mybp) from Alan Kazlev and Toby White, http://www.palaeos.com/Paleozoic/Cambrian/Cambrian.htm

Compare these two re-creations of the Cambrian sea floor below with the one above for the Vendian/Ediacaran era. Both Cambrian reconstructions are dominated by the super-predator anomalocaris, but with a huge variety of other animal types. For the first time, predators hunted other animals that protected themselves with shells, spines, and other devices. (Nat. Mus. Mat. Hist., http://www.nmnh.si.edu/paleo/shale/pamsci.htm; Royal Tyrrell Museum, picture by M. Rieke)

Reconstruction of anomalocaris, the dominant predator that grew up to two feet in length	This awesome hunter (4 - 6 times larger than any other animal) swam the seas searching for food, which it captured with its claws and pulled into a round mouth lined with teeth. animation from D. Quinn, Paleoindustrial,  http://www.paleoindustrial.com/Anomalocaris%20-%20Swimming.htm.

These specimens of other creatures (typically a few inches long) are based on fossils from the Burgess Shale, in the Canadian Rockies on the border between British Columbia and Alberta.

Wiwaxia	Opabinia
Halucenia	Trilobite

The oldest known vertebrates are small (1 inch long) fish from the early Cambrian. (from BBC, http://news.bbc.co.uk/2/hi/science/nature/504776.stm)	(from Stephen Greb through Kentucky Geological Survey, http://www.uky.edu/KGS/education/Imgcambrian.htm

This Aysheaia from the Burgess Shale is an example of an onychophoran, a family of animals that has been less successful than arthropods (insects, spiders)  or vertebrates. (from Living Landscape  http://www.livinglandscapes.bc.ca/cbasin/fossils/fig6.html)	This velvet worm, however, is a surviving example. (from Encyclopedia Brittanica Concies, http://concise.britannica.com/ebc/art-6767/Onychophoran)

The Cambrian era ended with a mass extinction, for which we are unsure of the cause.