Mammalian Evolution and Skeletal Changes

What is the primary reason mammals share many features?

• They all have the same number of limbs.

• They have a common ancestry that evolved over millions of years.

• They all have the same diet.

• They all live in similar environments.

Which period did some of the features that unite mammals evolve?

• Jurassic

• Cretaceous

• Carboniferous and Permian

• Devonian

How did the mammalian braincase evolve over time?

• It became larger and more rounded.

• It developed additional bones.

• It became smaller and more angular.

• It remained the same size.

What change occurred in the mammalian lower jaw during evolution?

• It developed into a beak.

• It became a single bone called the dentary.

• It became composed of multiple bones.

• It remained unchanged.

What skeletal change allowed mammals to move their heads in 'yes' and 'no' movements?

• The elongation of the spine.

• The modification of the first two vertebrae.

• The fusion of the skull bones.

• The development of a longer neck.