section 2 characteristics of mammals
DESCRIPTION
Endothermy Allows mammals to live in cold environments and remain active Provides energy for strenuous activities like migrating Fast metabolism requires more energy Cold environments- blubber & thick furred animalsTRANSCRIPT
Chapter 43Mammals
Section 2Characteristics of Mammals
Endothermy• Allows mammals to live in cold
environments and remain active• Provides energy for strenuous activities
like migrating • Fast metabolism requires more energy• Cold environments- blubber & thick
furred animals
Circulatory System• Two atria and two ventricles• Septum- wall of tissue separates
ventricles• No mixing of deoxygenated and
oxygenated blood• Complete septum- adaptation that allows
mammals’ bodies to transport oxygen more efficiently
Respiratory System• Efficient gas exchange• Large lungs- many alveoli- small sacs
where gas exchange occurs• Expand ribcage and take in air through
lungs• Diaphragm- contraction enlarges thorax
and increases thoracic activity- breathing
Feeding & Digestion• Incisors- cut food• Canines- grip, puncture, & tear• Premolars- shear, shred, cut, or
grind• Molars- grind, crush, or cut• Baleen whales- baleen- thin
plates of keratin- trap prey
Digesting Plants• Cellulose- polymer of sugar
glucose- hard to digest• Stomach- four chambers• One chamber = true stomach• Rumen- another chamber-
contains symbiotic microorganisms
Digesting Plants• Partly digested in rumen, then
regurgitated, chewed again and swallowed again
• Animals may regurgitate multiple times
• Ruminant animals- cows, sheep, goats, giraffes, deer
Digesting Plants• Horses, zebras, rodents, rabbits, &
elephants- cecum • Cecum- large sac that branches from
small intestines and ferments food• Animals with a cecum do not chew
cud
Nervous System• Mammal brain is large• Cerebrum- outer region of brain• Sense organs, movements, behavior,
memory, learning• Vision, hearing, smell, touch, taste• Echolocation- emit high-frequency
sound-waves, which bounce off objects
Development• Mammals develop differently
Monotremes• Lay one to two eggs• Incubate by body heat• Yolk nourishes young• Once young hatch, female feeds
young milk until fully developed
Marsupials• Develop in uterus for short time• When only 2-3 cm, young develop
in mother’s pouch and attach to a nipple to feed
• Young stay in pouch for several months
Placental Mammals• Well-developed young are born
live• Placenta provides nourishment &
oxygen• After birth, infants feed on milk for
several weeks or months
REVIEW!!!• A mammal eats about ten times as
much food as a lizard of the same size. Explain this difference.
• Describe the function of a rumen.