Birds and Mammals

Objectives

• Describe bird reproduction
• Describe mammal structure and function
• Outline reproduction in placental mammals
• Explain how marsupials reproduce

Adaptations for Flight

• Hollow, lightweight bones
• No jaw
• Air sacs that push air into lungs
• Crop to store and moisten food for digestion
• Gizzard with swallowed stones

Birds

• Portion of brain for flight most developed
• High level of intelligence
• Poor sense of smell
• Excellent eyesight

Bird Reproduction

• Incubation/brooding
• Care for hatchlings

Mammals

Defining Characteristics

• Females have mammary glands
• Have hair or fur

Mammals often have...

• sweat glands
• alveoli in lungs
• a four-chambered heart
• three tiny bones in the middle ear
• four types of teeth

Carnivores have simple digestive systems. Herbivores have more complex digestive systems.

The front part of the brain, the cerebum, which is used for memory and learning, is particularly large in mammals.

The neocortex covers the brain. The human neocortex has a lot of folds.

Therian Mammals

• Uterus
• Vagina
• Divided into marsupials and placental

Placenta

• Spongy structure
• Membranes and blood vessels
• Passes oxygen and nutrients from mother to fetus
• Passes CO2 and waste from fetus to mother
• Blood exchange without mixing

Marsupials

• Embryo born at an early, immature stage
• Embryo nourished by yolk sac rather than placenta