The common garter snake (Thamnophis sirtalis) has evolved a…

The common garter snake (Thamnophis sirtalis) has evolved a resistance to the toxins of their prey, the rough skinned newts (Taricha granulose).  As the newts continue to evolve more potent toxins, the garter snakes evolve an increased amount of resistance to the poison.   This interaction can best be described as [1] Cellulose-digesting bacteria live in the digestive tract of cows.  The bacteria digest the plant material that the cow cannot.  The cow can use a source of food unable to other animals and the bacteria gets a nice, safe cozy environment in which to live.  This is an example of [2] Certain types of silverfish move along in permanent association with marching columns of army ants and share the abundant food caught in the ant raids.  The ants derive no apparent benefit or harm from the silverfish.  This is best described as [3] Plasmodium is an amoeba (a very small organism) that lives part of its life cycle in human red blood cells.  The presence of the Plasmodium in humans causes malaria, a potentially fatal disease. This is an example of [4]

Looking at other species of finches… During drought years…

Looking at other species of finches… During drought years on the Galapagos, small, easily eaten seeds become rare; large, hard-cased seeds are left.   Only birds with large beaks can eat the hard-cased seeds.  Over time the average size of the beaks in a bird population increases.  This is an example of    

As you know, we use animal models to study human disease.  T…

As you know, we use animal models to study human disease.  The EAE (experimental allergic encephalitis) mouse is used for research on multiple sclerosis.  EAE mice have defective myelin sheaths on CNS nerve cells.  Which of the following statements about EAE mice is ACCURATE?

You are a paleontologist (someone who studies fossils) and a…

You are a paleontologist (someone who studies fossils) and after spending many years collecting fossilized  shells from different layers of sediment. You estimate that the oldest shell you found is 8 million years older than the most recently fossilized shell you found. Based on your where you found your shells (depicted in the image below), what can you reasonably conclude about the evolution of the snail shells you collected?