Triassic

Advantages to Mammals: 

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

Muscles attach to the outside of the skull 

Mammals chewing muscles moved from the inside of the skull to the outside, this gives the brain more room inside of the skull so it can grow bigger. Bigger brains lead to smarter animals. 

Larger, more advanced chewing muscles

When muscles move the the outside of the skull, the shape of the skull changed to accommodate them. This lead to the growth of a zygomatic arch, which is the structure that allows muscles to attach to the lower jaw and the upper jaw. This meant that the muscles can grow and move freely, without sacrificing bite size. Mammals could now have a stronger bite and chew in different ways. 

Being able to move and chew in different ways allowed mammals to eat many different types of prey. While reptiles were limited to smaller bites and weaker jaws, mammals were able to eats plants, small animals, insects and more! Their varied diet allowed them to get enough food to survive after the meteorite destroyed so many types of food. 

 Protecting the brain

A reptile brain is protected only by the skull and a layer of skin, mammal brains are protected by the skull, outer muscles, skin and hair or fur. Mammals brains are very well protected because they are selected for in evolution, smarter animals with large brains get more food, mate more frequently, and pass their genes onto the next generation.