26 Facts About Cambrian
What is the Welsh Explosion?TheCambrian Explosionrefers to a period around 541 million year ago when a rapid burst of evolutionary change come , leading to the appearance of most major fauna groups . This effect , lasting about 20 - 25 million years , view a dramatic increase in the complexity and diversity of life forms . Before this period , most organisms were bare , single - celled , or subdued - corporal ....