Mammals

Question 1

Major Characteristics of Mammals?

Answer 1

Endothermic, Hair, Completely divided heart,
Milk (Mammary Glands), Single jawbone Specialized Teeth

Question 2

Who gave rise to the first Mammals and how long ago?

Answer 2

Synapsids 300 mya

Question 3

Diversification of 3 types of Mammals?

Answer 3

1- Monotremes: oviparous (layed eggs)
2- Marsupials: viviparous (gave birth to live young) + pouch to stay in after birth
3- Placental Mammals: viviparous + fetus gets nourishment from placenta

Question 4

Describe the Circulatory System?

Answer 4

2 atria + 2 ventricles, with the septum dividing the aria.

Question 5

Purpose of the septum?

Answer 5

Prevents oxygenated and deoxygenated blood from mixing.

Question 6

Describe the Respiratory System?

Answer 6

They have lungs, which have millions of alveoli (small sacs) for gas exchange. They have 2 breathing mechanisms: Using ribs to expand the thoracic cavity, and Using a diaphragm below the rib cage.