Mammals

1
Mammals

• Unit VI
• Chapter 32

2
Mammals

• All mammals are characterized by 2 notable
  features
• Hair and mammary glands (produce milk to nourish
  young)
• All mammals breathe air, have 4 chambered hearts,
  and are endotherms that generate their body heat
  internally
• The first true mammals appeared during the late
  Triassic Period, about 220 million years ago

3
Body Temperature Control in Mammals

• Body Temperature Control
• Endothermic
• External body hair
• Subcutaneous fat (just under the skin)
• Sweat glands for cooling
• These are all examples of homeostasis

4
Mammal Feeding

• Early mammals ate insects
• As mammals evolved, the form and function of
  their jaws and teeth became adapted to eat food
  other than insects
• Modern mammals have specialized teeth
• Canines, incisors, molars, and premolars
• A mammals digestive tract is adapted to break
  down and absorb the type of food that it eats
• Cows and their relatives have a stomach chamber
  called a rumen (contains symbiotic bacteria that
  digest the cellulose of plants)

5
Mammal Respiration

• All mammals, even those that live in water, use
  lungs to breathe
• Mammals inhale when muscles in the chest lift the
  rib cage up and outward increasing the volume
  of the chest cavity
• A powerful muscle called the diaphragm pulls the
  bottom of the chest cavity downward and as a
  result, air is pulled into the lungs
• When the diaphragm relaxes, air is pushed out of
  the lungs

6
Mammal Circulation

• The mammalian circulatory system 4 chambered,
  double loop

7
Mammal Excretion

• The kidneys of mammals help maintain homeostasis
  by filtering urea from the blood, as well as by
  excreting excess water or retaining needed water

8
Mammal Response

• Mammals have the most highly developed brains of
  any animals
• The brain consist of 3 main parts
• Cerebrum (thinking and learning)
• Cerebellum (muscle coordination)
• Medulla oblongata (involuntary body functions)
• Mammals rely on highly developed senses to
  provide information about their external
  environments
• Smell
• Sight
• Hearing
• Touch
• Taste

9
Mammal Reproduction

• Mammals reproduce by internal fertilization and
  are classified into 3 groups based on their modes
  of development and birth

10
Monotremes and Marsupials

• Monotremes lay eggs
• Duckbilled platypus spiny anteaters
• Marsupials bear live young that complete their
  development in a pouch
• Kangaroos, koalas, wombats

11
Placental Mammals

• Placental mammals get their name from an internal
  structure called the placenta, which is formed
  when the embryos tissues join with tissues from
  within the mothers body
• In placental mammals, nutrients, oxygen, carbon
  dioxide, and wastes are exchanged between embryo
  and mother through the placenta
• After birth, most placental mammals care for
  their young and provide them with nourishment by
  nursing

12
Groups of Placental Mammals
13
Groups of Placental Mammals
14
Groups of Placental Mammals
in general, primates have binocular vision, a
well-developed cerebrum, fingers and toes, and
arms that can rotate around their shoulder joints