Class Mammalia Flashcards

Mammals are characterized by their ability to give live birth (with exceptions like monotremes) and the presence of mammary glands for nourishing young.
They are warm-blooded (homeothermic) and maintain a constant body temperature through metabolic regulation.

Subclass Prototheria includes monotremes, the egg-laying mammals.
Subclass Theria is divided into:
- Infraclass Metatheria (marsupials with pouches, like kangaroos).
- Infraclass Eutheria (placental mammals that nourish young through a placenta).

Four-chambered heart enables efficient blood circulation.
Differentiated teeth: incisors for cutting, canines for piercing, and molars for grinding.
Enucleated red blood cells, unlike birds, which have nuclei in theirs.
Presence of a hard secondary palate allows chewing and swallowing.
Vocal cords and larynx facilitate sound production; a muscular diaphragm aids in respiration.
Tonsils and three inner ear bones (malleus, incus, stapes) are distinctive features.

Mammals require a significant intake of food to maintain their high body temperature.
Four main dietary categories: herbivores, carnivores, omnivores, and insectivores.

Mammals evolved from therapsids, which were advanced forms of reptile ancestors.

Advanced kidneys filter blood more effectively, while the urinary bladder holds and manages water needs.
Digestive tract length varies by diet:
- Short for predators, long for herbivores, medium for omnivores.

Most primitive mammals, laying eggs and exhibiting limited endothermic capabilities.
They lack nipples and have limbs adapted for swimming and digging.

Young are nourished via a placenta during gestation, allowing for advanced development before birth.
Most mammals fall under this infraclass.

Order Chiroptera: Bats utilize echolocation for navigation and hunting.
Order Primates: Distinguished by the presence or absence of tails; includes both apes (no tails) and monkeys (have tails).
Order Carnivora: Comprised of canines, felines. Includes two suborders: Caniformia (dog-like) and Feliformia (cat-like), with specialized carnassial teeth for processing flesh.
Order Cetacea: Whales are adapted for diving with dorso-ventral undulations, and also use echolocation.
Order Rodentia: Rodents possess a unique dental structure with continuously growing incisors.
Order Artiodactyla: Includes ungulates like pigs and deer, with variations in stomach type (simple vs. ruminating).

Homologous structures indicate shared ancestry, while analogous structures arise from similar evolutionary pressures.
Vestigial structures are remnants of ancestral features that no longer serve their original function.

Three muscle types present:
- Skeletal (movement),
- Smooth (involuntary movements),
- Cardiac (heart function).
Various skeletal joints including ball and socket, hinge, pivot, saddle, condyloid, and plant.

The central nervous system comprises the spinal cord and brain, while the peripheral system includes sensory and motor nerves.
Respiratory system involves the larynx and diaphragm to facilitate breathing and voice production.