Diversification:
So, what do we observe? While we see an increasing diversification of invertebrates in terrestrial circumstances, vertebrates take their time coming out. The first vertebrates that do come out, old fish face here, Ichthyostega, a Sarcoptyergian fish, possessed a fish-like tail and a sprawling gait and came out into a world that, from our perspective, wouldn't be that dissimilar to the present day. You'd recognize trees and shrubs and herbs. As it turns out, when we see the vertebrates first appear, they tend to appear in an equatorial zone.
This is also where the first land plants appeared, in the paleo-equatorial region. The Mississippian and Pennsylvanian times are also known as the Carboniferous period that was about 340 to 300 million years ago. Thus, the first radiation of terrestrial plants in this paleo-equatorial zone is subsequently followed by the radiation of terrestrial animal life.
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Narrative Index
BioForum Index
