Lesson 26b: Class Mammalia (chordates p3) Flashcards
What is Class Mammalia?
The mammals!
What are 3 characteristics of Mammals?
A. Hair covers at least part of their body at some time during their life. (((THEY ARE THE ONLY GROUP OF ANIMALS WITH HAIR)))
B. Two pairs of limbs: two forelimbs and two hindlimbs specialized for different functions (exception: animals from the cetacea—whale—order)
C. Endothermic strategies for maintaining body temperature
What does hair, a characteristic all mammals have, do for them?
- Provides insulation
- Regulates body temperature
- Protects skin
- Can serve as camouflage
- Provides sensory feedback from surroundings
What are mammals endothermic strategies for maintaining body temperature?
- Food consumed to fuel metabolism produces body heat
- Body reacts with uncontrollable muscle spasms in cold climates to keep warm
- Some use hibernation in cold seasons to survive: metabolism, heart rate, and respiration slow down until the weather warms.
- Animals like bears enter a state of torpor: deep sleep with decreased heart rate but maintain warm body temperatures (((BUT NOT HYBERNATION)))
- Aquatic mammals have a thick layer of fat called blubber to keep them warm.
a) Acts as an energy source
b) Increases buoyancy in water
Tell me about a mammals circulatory system…
They have a circulatory system composed of a 4-chambered heart delivers oxygen and nutrients throughout the body and removes waste products
Tell me about mammals (in general) respiratory system…
- Mammals have large lungs in relation to body size because mammals require more oxygen to maintain their body temperature
- Mammals are the only class of animals that have a muscular diaphragm
a) Separates their body cavity into the abdominal and thoracic cavities (chest cavity)
b) When the diaphragm contracts, it expands the lungs and causes air to enter; when it relaxes, the lungs contract and air is exhaled.
Tell me about the special features in an aquatic mammals respiratory system…
- Aquatic mammals have specialized structures for breathing:
a) Animals in the order cetacea have blowholes on the top of their head for breathing. b) Animals in the order sirena have valves on their nostrils which open when they’re above the surface of the water and close when they’re below the surface of the water.
How do all mammals reproduce?
- Reproduce via internal fertilization
How do placental mammals reproduce?
- Most mammals are placental mammals; they have young that develop viviparously, meaning inside the mother.
a) Placenta forms during the development inside of the mother b) The placenta nourishes the embryo by transferring nutrients and oxygen from the mother’s blood. c) Waste products from the embryo are delivered to the placenta and transferred to the mother, exiting via the mother’s waste system
How do non-placenta mammals reproduce?
Two types:
a) Monotremes: egg laying mammals
(1) Five known species
(2) No placenta is formed
(((like a bird)))
b) Marsupials: pouched mammals
(1) Bear live young, but they only develop in the mother for a few days
(2) Because of short developmental period, no placenta is formed
Briefly explain mammals mammary glands…
They produce milk to nurse their young
- Mammary glands only fully develop in females, although breasts are present in both males and females
- Exception: The Dayak fruit bat males have mammary glands that produce milk to feed young.
(((the name mammal comes from the them having mammary glands)))
Lesson 26b: Class Mammalia (chordates p3) video summary
file:///C:/Users/trgan/Sync/LisA%20school/Lesson%2026b%20Phylum%20Chordata%20p3%20Class%20Mammalia%20video%20summary.mp4
Do all primates walk on two legs.
No the majority of them spend most of their time walking on four legs
Which of the following group of mammals is NOT a placental mammal?
a. Marsupials
b. Primates
c. Carnivora
d. Rodentia
a. Marsupials
