Cambrian Explosion: more early brains (Introduction)

by David Turell , Tuesday, November 10, 2015, 00:45 (3090 days ago) @ David Turell

Lobed brains with optic nerves are found in a species (seven specimens) from 520 million years ago. Fossilization of nervous tissue is rare. Much of the article explores how it might occur:-"The researchers examined the seven new specimens with a scanning electron microscope, revealing a common neural architecture which is preserved, to a greater or lesser extent, in all of them - three distinct segments of brain tissue, plus the optic lobes and optic tracts, which led from the eyestalks to the front of the brain. Chemical analyses of the specimens also revealed that the nervous tissue is preserved as a flat carbon film, sometimes overlaid with pyrite crystals.-***-"When Strausfeld and his colleagues first examined Fuxianhuia, however, they were surprised to discover that it had a complex brain consisting of three fused segments with a rich supply of blood vessels. This brain organization closely resembles that seen in extant insect species, suggesting that the brains of certain arthropod species, such as the brine shrimp, regressed to less complex nervous systems as they evolved. The human brain is also partitioned into segments, most prominently during embryonic development, but also throughout life, and so it seems the basic ground plan for all nervous systems was laid down more than half a billion years ago, and has remained unchanged ever since." (my bold)-Comment: Brains are very complex, especially with eyes and optic cortex and before the Cambrian, nothing but simple sheets of cells as multicellularity began. Note my bold! Pattern planning again, surprise! For Darwin's vision theory all we have is eye spots and then full-blown eyes. How did the Ediacarans do this? Not by chance. Granted neurons had appeared before this, but not in complex networks as found in brains. Logical solution, design!