Human Ecology Discussion Board – Week 3 Response

During the mid-cretaceous period, there was a significant difference in plant and animal life when compared to modern days. As we are aware, there is nearly zero overlap in animal life when comparing tropical and polar regions. However, when the mid-cretaceous period was prevalent, there was such similarities in plant and animal life among all climates. Specifically, molluscs barnacles, crabs, ammonites and sea urchins were found in all water regions. On land, dinosaurs such as the tyrannosaurus, stegosaurus, and Iguanodon walked the earth while pterosaurs ruled the skies near the equator and up to 45 degrees north. In terms of plant life at this time, ferns and other tropical plants were found as far as modern day Alaska and the development of angiosperms became relavent in the temperate climates.  

Evidence of increased levels of carbon dioxide and greenhouse gases in the atmosphere at the time implies that the mid-Cretaceous period was the warmest in Earth’s history. Because of this, there was very little difference in overall climate at any point on Earth, evidenced by the fossil evidence of ferns at the South Pole. Because of this fairly mild climate the evidence certainly coroborates a fairly uniform grouping of plants an animals residing world-wide.