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|Mom and Two Daughters||by Mark Dumont on Flickr|
- are vertebrate animals (means they have a backbone or spine)
- are endothermic or “warm-blooded,” endothermic animals regulate their own body temperate which allows them to live in almost every climate on Earth
- have possession of hair on their bodies
- produce milk to feed their babies
- have sweat glands
|Family Bath Time||by Steve Wilson on Flickr|
There are almost 4,000 known species of placental
mammals. Humans, Cats, Dogs, mice and whales are all placental mammals and
are all related.
- Largest group of mammals, the placentals, have
a placenta which feeds the offspring during gestation.
- Before birth, the young are nourished through a
- The placenta is a specialized embryonic organ that
is attached the mother's uterus and delivers oxygen and nutrients to the young.
|Bilateral Symmetry||by Furryscaly on Flickr|
- The majority of mammals have seven cervical
vertebrae bones in the neck. Example:
bats, giraffes, whales, and humans.
- The few exceptions include
the manatee and the two-toed sloth, which have only six
cervical vertebrae, and the three-toed sloth with nine cervical
|Baby Gray Squirrel||by audreyjm529 on Flickr|
- In air-breathing vertebrates, respiration takes place
in the respiratory organs called lungs.
- The passage of air into the lungs to supply the
body with oxygen is known as inhalation, and the passage of air out of the lungs to expel
carbon dioxide is known as exhalation; this process is collectively called breathing or ventilation.
- In humans and
other mammals, the anatomical features of the respiratory
system include include trachea, bronchi,bronchioles,
lungs, and diaphragm.
- Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood.
- This exchange process occurs in the alveoli air sacs in