Characteristics of Mammals (Pair Functions and Mammary Gland (Definition…
Characteristics of Mammals
Pair Functions and Mammary Gland
Definition of Mammary Gland:
Insulation:One of the most important functions of hair is to insulate against the cold.
Functions of hair:
Mammary glands produce and secrete milk that nourishes developing young. Recall that if an animal has feathers, it is a bird. In a similar way, if an animal has hair, it is a mammal.
Camouflage:The striped coat of a Bengal tiger allows it to blend into its natural habitat (the jungle).
Sensory devices: In some cases, hair has been modified into sensitive whiskers.
Waterproofing:You might know how cool it feels when you come out of a swimming pool on a hot day.
Herbivores, such as rabbits and deer, eat plants.
Carnivores, such as foxes and lions, eat mostly herbivores.
Insectivores, such as moles and shrews, eat insects and other small invertebrates.
Omnivores, such as raccoons and primates, eat both plants and animals.
Mammals have adaptations for finding, catching, chewing, swallowing, and digesting food. These adaptations determine a mammal’s structure and function.
Plants are more difficult to digest than meat, so an herbivore’s digestive tract is longer than a carnivore’s.
The kidneys of mammals filter urea from the blood and excrete it.
Urea is a waste product of cellular metabolism.
The kidneys also maintain the proper amount of water in the body to maintain homeostasis.
They enable animals to live in extreme environments by controlling the body’s water.
Mammals are the only animals that have diaphragms.
A diaphragm is a sheet of muscle located beneath the lungs that separates the chest cavity from the abdominal cavity.
As the diaphragm contracts, it flattens. This makes the chest cavity larger, enabling air to enter the lungs. As the diaphragm relaxes, the chest cavity becomes smaller, and air is exhaled.
Oxygen then moves by diffusion into blood vessels. High levels of oxygen are needed to maintain the mammal’s high metabolism.
sweat glands in the skin are stimulated to secrete sweat that evaporates from the skin.
For other mammals that do not sweat, panting cools the body.
Body temperature is regu- lated by internal feedback mechanisms that send signals between the brain and sensors throughout the body.
The source of body heat is internal, the result of heat produced by a high metabolic rate.
mammals can regulate their body temperatures internally to maintain homeostasis
Cellulose found in a plant’s cell walls can be a source of nutrition and energy. Mammals do not have enzymes to digest the cellulose.
Some herbivores have bacteria in their stomachs that will break down the cellulose.
These mammals are called ruminants and have large, four-chambered stomachs. Cattle, sheep, and buffalo are all ruminants.
As ruminants feed, bacteria in the first two chambers partially digest the grass into a material called cud. Ruminants bring the cud back up into their mouths and chew it for a long time.
This further crushes the grass fibers. After they swallow the cud, it eventually reaches the fourth chamber where digestion continues.
Mammals have four types
of teeth: canines, incisors, premolars, and molars.