Jurassic

Advantages to Mammals: 

Read through the description and summarize the advantages that lead to the rise of mammals after the mesozoic era. 

Enlarged Lower Jaw

Of the three lower jaw bones in early reptiles and mammal ancestors, only the dentary remained in the same position. This bone held teeth and it got bigger as mammals got more teeth that became more specialized. When this bone got larger, the mouth opening got larger as well, expanding the types of foods mammals can eat.

Simplifying the Jaw

Early reptile jaws are made of three separate bones, the articular, angular and dentary, these are sutured together and each suture is a weak point on the jaw. Mammals single jaw bone is stronger overall since there is no suture points. This also allowed more room for muscles to attach to the bone so that mammals could control how their jaws moved more than reptiles. You will see that reptiles have smaller jaws and smaller bites.  

More teeth = More food

With more room on the dentary, more teeth can fit on the lower jaw. With this room teeth can change shape based on the position, you will see molars in the back of the mouth for grinding and chewing and sharper teeth in the front of the mouth for ripping and grabbing. Having a variety of teeth shapes and functions allow mammals to eat a large variety of prey and survive better.