The Cambrian Explosion By Andy Gorman Cambrian n

The Cambrian Explosion By Andy Gorman

Cambrian? n n n In the Cambrian period, the super continent of Pangaea was breaking up into smaller parts Many climate changes took place at this time. Oxygen was increasing Carbon Dioxide was decreasing (this caused the planet to cool down) There was a huge glacial movement and a very harsh ice age. And after the ice age was finished temperatures rose to levels higher than they are today.

What is the Cambrian Explosion!? !? !!!!!!!!111111 11 one At first look, the Cambrian explosion would sound totally sweet. Just think, explosions! n But in fact, it is only semi-sweet (not really) n What actually happened, was a lot of complex organisms appeared between 543 and 530 million years ago. n Organisms like brachiopods, arthropods and echinoderms appeared in large variations n

Why So Much Life? Many Theories have been created to explain this sudden increase in life, but many contradict each other. n One theory was that the changing climate could have caused some of the life created in the period. n

Evolution? n n n This Cambrian Explosion drew attention to the evolutionary theory. Charles Darwin even brought it up in his book, Origin of Species. It is at this period, many organisms attained or improved preservational characteristics, or in lay man’s terms, hard parts.

n. GIVE ANDY AN A

View points Everybody agrees that there was a big biological event that happened at that time. n Where there is controversy is whether this event was a true radiation of metazoan forms from a single Precambrian ancestor or an explosion of fossils rather than phyla n

One Ancestor There is a sudden increase in fossils at the time n Trace fossils also increase in behavior and in abundance. n Soft-bodied Precambrian faunas can be preserved, so why are there no assemblages of 'true' metazoan soft-bodied faunas from the Precambrian n

Just abundance of Fossils? n n n Soft bodied organisms fossilize over only exceptional circumstances. cladistic analysis shows that the divergence times of most Cambrian organisms must have occurred in the Precambrian organisms could have been very small and therefore fossilization would have been impossible