Chapter 32.1 Notes Hannah Reagan 3 rd period
Jan 03, 2016
Chapter 32.1 Notes
Hannah Reagan3rd period
Mammals
Class Mammalia Have hair and mammary glands
(produce milk to nourish the young) Also, mammals breathe air, have
four-chambered hearts, and are endotherms that generate body heat internally
Evolution
Though you can’t see hair nor mammary glands in fossils, some fossilized mammal characteristics include: lower jaw connected by a joint directly to the skull, teeth that are replaced once in a lifetime, and discrete features of limbs and backbone
Mammals descend from reptiles First appeared during late Triassic
period; 220 million years ago
Body Temperature Control
High metabolic rate HairSubcutaneous fat: layer of fat
located beneath the skin Some have sweat glands and others often pant
Feeding As mammals evolved, the form and function of
their jaws and teeth became adapted to eat foods other than insects
Because of high metabolic rate, mammals have to eat 10 times more food as a reptile
Specialized teeth: 1. incisors
2. canines 3. molars 4. premolars
Carnivores have short intestine because digestive enzymes can quickly digest meat
Herbivores have long intestine because tough, fibrous plant tissue is hard to break down
Rumen: stomach chamber in which newly swallowed plant food is stored and processed
Respiration
Circulation
All mammals use lungs Diaphragm: powerful muscle that pulls the
bottom of the chest cavity downward, which further increases volume when breathing in
2 separate loops with a four chambered heart
Right ventricle and atrium pump oxygen poor blood from body to lungs. Left ventricle and atrium pump oxygen rich blood from lungs to the rest of the body.
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.
Kidneys also help retain sugars, salts, etc.
Kidneys allow mammals to live in different habitats just by being able to stabilize the amount of water in the body efficiently
Response
Highly developed brains: main parts include cerebrum-thinking and learning, cerebellum-muscular coordination, and medulla oblongata-involuntary body functions
The cerebrum outer layer is the cerebral cortex: center of thinking and other complex behaviors
Many have well developed sense of smell, sight, and hearing
Other super cool fun stuff
Endocrine glands regulate body activities by releasing chemicals called hormones that affect other organs and tissues
Immune systems help stop pathogens from infecting the mammal (includes skin barrier, and specialized cells that recognize and destroy pathogens)
Movement
Backbone Shoulder and pelvic girdles Diversity in limb bones of climbers,
runners, diggers, flyers, and swimmers. Pictures of limbs on page 826!
Reproduction
Internal fertilization All newborn mammals feed on their
mother’s milk Strong parental care and interaction
1. What is the cerebral cortex?
A. Covering of the olfactory bulbB. Outer layer of the cerebrumC. Helps in excretionD. Another name for the medulla oblon
gata
2. What defines a mammal?
A. Four chambered heartB. Breathe airC. Generate their body heat internallyD. All of the above
3. When and about how long ago did the first mammal appear?
A. Triassic Period; 220 million years ago
B. Jurassic Period; 206 million years ago
C. Permian Period; 260 million years ago
D. Carboniferous Period; 330 million years ago
4.What system is the kidney a part of?
A. NervousB. DigestiveC. ExcretoryD. Circulatory
5. How do mammals reproduce?
A. Asexual reproductionB. External fertilizationC. Internal fertilizationD. They don’t reproduce
CORRECT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
WRONG!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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