essay on my favorite pet dog Edison Forbes
This is a story about my first time with my dog and a friend's dog.
Peter Ward led an effort to catalog the fossil record before and after Romer’s Gap, which found a dramatic that did not resume until about 340-330 mya. Romer’s Gap seems to have coincided with low-oxygen levels of the late Devonian and early Carboniferous. If coincided with a halt in colonization, just as the adaptation to breathing air was beginning, the obvious implication is that low oxygen levels hampered early land animals. Not just the lung had to evolve for the up-and-coming amphibians, but the entire chest cavity had to evolve to expand and contract while also allowing for a new mode of locomotion. When amphibians and splay-footed reptiles run, they cannot breathe, as their mechanics of locomotion prevent running and breathing at the same time. Even walking and breathing is generally difficult. This means that they cannot perform any endurance locomotion but have to move in short spurts. This is why today’s predatory amphibians and reptiles are ambush predators. They can only move in short bursts, and then have to stop, breathe, and recover their oxygen deficit. In short, they have no stamina. This limitation is called . The below image shows the evolutionary adaptations that led to overcoming Carrier's Constraint. Dinosaurs overcame it first, and it probably was related to their dominance and the extinction or marginalization of their competitors. (Source: Wikimedia Commons)
This the story about my first time with my dog Charlie.
One of Peter Ward’s recent hypotheses is that animals that adapted to the changing conditions, particularly when oxygen levels crashed, survived the catastrophes to dominate the post-catastrophic environment. In the late Permian, several therapsid lines developed , which may have been used for respiratory water retention in a world where oxygen levels were crashing. This is a controversial issue, and related to the controversy over when reptiles developed . The therapsid ancestors of mammals, , first appeared about 260 mya, and had many .