Re: what percentage of land during the time of the dinosaurs is now under water

Michael:

As for the lands covered by oceans/seas during the Mesozoic (Triassic [245- 208mya], Jurassic [208-144mya], Cretaceous [144-65mya]), I can only speak for a few continents. Australia, Europe, North America, Asia, and presumably others had experienced a large rise in the sea as tectonic activities pushed us together in the Permian (Pangaea) and pulled us apart again in the Mesozoic. During the Mesozoic we started the various courses of rifting that lead to our present configuration. The vast inland seas began to form during the Triassic and Jurassic and continued in the Cretaceous, waxing and waning continuously. At any given time I would say the percentage of land/water has changed form the normal 70% water -- 30% land, to roughly 80% water. This is an estimate based on preserved marine deposits (Tethys sea, Sundance seaway, Australian seaway). Without an extensive lit search I cannot tell you an exact area, but I believe that should be a close estimate (perhaps liberal).

Times more closely related to ours will be much easier to deal with. No significant change in ocean levels. The dawn of man (by this I mean bipedal primates) is around 4-5mya. During the last 5 million years, we have been experiencing worldwide glacial/interglacial oscillations. The overall sea levels have not changed greatly. Coastal areas have seen some modifications. During full glacial extent, you may have seen a 100+ metre drop in sea level, and during full retreat around a 20+ metre rise above modern sea levels. The changes in seas for the last five million years has been predominantly due to glacial advance and retreat. The sea level would not have greatly impacted the evolution of humans, save for potential climate changes because of the glaciers.

For a timeline of human evolution, and a fossil index, check out the talkorigins link below (it's fantastic). There are very few missing links. At this time we have a 600,000 year resolution on hominid speciations. With the average life of a given species being 2-3 million years, I'd say that this is a pretty great resolution. By definition, we are ALL intermediates. There really is no "missing link," that is a misnomer. Granted we will continue to find more specimens, and potentially more species, but the evolutionary structure of hominids is well established. Most of the hominid evolution took place in Africa, and not on the shores of the oceans (relatively speaking). For more on human evolution check out www.talkorigins.org.

http://www.talkorigins.org/faqs/homs/species.html
http://www.dc.peachnet.edu/~pgore/geology/geo102/mesozoic.htm
http://www.alphalink.com.au/~dannj/marine.htm (good animation of Australia's changes during the Mesozoic)