Anatomical and Physiological Evolution

Anatomical and Physiological Evolution
Peggy Robb
Bio-101
March 29, 2012
Roberto Jimenez
Anatomical and Physiological Evolution
As populations evolve and the environment changes, genes naturally select features in anatomy and physiology that reinforce the survival of a species. To escape the dangers of extinction a species gene pool will make changes and pass those changes down to the next generation. This is evolution. Sometimes these changes are observable, such as the case of the English moth. Sometimes these changes are only observable after looking back over history, such as the case of the lungfish. This paper will be a study on the anatomical and physiological evolution of the lungfish.
Evolution of Lungfish
Sarcopterygii are fleshy-finned fish that first appeared in the Early Devonian period. The Dipnoi are believed to have evolved from this period. The Dipnoi are unusual in their features and the way in which they have evolved over-time to adapt to their changing environment. These fish are an interesting study because of their body form, large size, detached distribution over Earth’s regions, and strange mode of life.
Lungfish Today
Most lungfish weigh up to 22 pounds and are around four-feet long. African lungfish can grow to be seven-feet long and weigh up to 40 pounds. It is interesting to know that lungfish can breathe with both gills and lungs. The lungfish uses its gills to breathe in lakes and swamps when it is the wet season in its region, and uses lungs to breathe during the dry season. The lungfish is also capable of “walking” on land to find mud or water to survive. When there is no water the lungfish will dig a hole in the mud, secrete a liquid around its body to keep from drying out, and aestivate (be dormant). The question that arises is how did the lungfish develop its leg like fins, lungs for breathing atmospheric air, and ability to lay dormant for such a long period of time.
Anatomical Evolution
The evolutionary line of the...