Mammals

General Characteristics Endothermic vertebrate with hair Warm-blooded Permits high level of activity at night and year- round (regardless of outside temperature) Females have mammary glands Function: make/secrete milk for young About 5000 species Ex: cats, dogs, humans, dolphins, elephants, kangaroo, whale, bat, rabbit, beaver, wolf, seal, mouse, platypus, chimpanzee, tiger

General Characteristics High degree of parental care Body covered by hair In some, hair is reduced in size – like humans All have an integument (external covering) Contains: sweat, scent, sebaceous and mammary glands

General Characteristics Breathe using lungs Excrete using kidneys Separate sexes Young nourished by milk (made by the mammary glands) Many have territories These are areas from which individuals of the same species will reside Will often resort to violence to protect these territories

classification Rodents Lagomorpha Hominids Insectivora Ex: mice, squirrels, rats, woodchucks Have two razor sharp incisors for gnawing Lagomorpha Ex: rabbits, hares, pikas All are herbivores Hominids Ex: humans, gorilla, orangutan, chimps Insectivora Ex: moles, shrews Diet consists of insects

Classification Carnivora Proboscidea Ex: weasels, seals, walruses, dogs, wolves, cats, bears Highly predatory animals, Contain teeth for tearing flesh Proboscidea Ex: elephants Largest of living land animals

Classification Perissodactyla Cetacea Ex: horses, donkeys, zebras, rhinos Often referred to as ungulates or the hoofed animals Cetacea Ex: dolphins, whales, porpoises Limbs are modified into flippers Live in aquatic environments only

Movement and response Skeleton Skeletal/bone make-up allows for: High-speed running Swimming climbing trees Movement of digits (fingers/toes) to help grasp objects Joints allow for a greater range of motion

Movement and response Hair: Has become a modified sense “organ” Purpose of hair: Spines of porcupines—protection Hair of most animals—insulation Vibrissae (whiskers)—provide tactile sense Slightest movement indicates minimal space available (cat/dog)

Movement and response Moveable eyelids Fleshy external ears Well-developed brain The largest brain in animal kingdom Cerebrum—processes info for thinking and learning High evolved brain allows for highly developed memory and capacity to learn topics/developmental milestones quicker

Movement and response Highly elaborate sensory organs Provide mammals with a high level of environmental awareness and responsiveness Senses: taste, smell, hearing, sight Most have great eyesight Many can’t see color Many will use echolocation to communicate and/or navigate Ex: Bats, dolphins

Digestion and Eating Teeth Mammalian teeth are both more complicated and more efficient than in other vertebrates Mammals are heterodonts (some of our teeth are different) Specialized for variety of functions: Includes: grind, stab, scissor, dig, chisel, sieve and lift (elephants tusks)

Digestion and Eating Teeth, cont. Teeth in mammals come in four different sorts: Incisors, Canines, Premolars and Molars. Not all mammals have all Use this variety to eat a wide variety of food Most placental mammals have between 20 and 40 teeth, while most marsupials have 30 to 50. As a general rule animals that feed on insects have more teeth than either herbivores or the larger carnivores.

Digestion and Eating Contain a secondary palate Separates air passageway from the food passageway Allows mammals to hold (and partially break down food) in mouths without interrupting breathing

Digestion and Eating Have many feeding adaptations Other adaptations: Insectivores are often small Herbivores have two groups Groups: browsers and grazers Have large molars adapted for grinding Carnivores have large canines Adapted for ripping/tearing meat Other adaptations: Ruminants (cattle, bison, goats) have a four- chambered stomach

Digestion and Eating Energy and Wastes Digestive tract Require much energy to keep a constant body temp Produce a variety of waste products (uric acid, urine, feces, etc) Digestive tract If mammals eats only plants, longer digestive tract Why? takes longer to digest plants/cellulose If eat only meat, shorter digestive tract

respiration Require a large amount of oxygen for respiration 2 organ adaptations for this: Diaphragm: Muscle that contracts and therefore, allows for more rapid/controlled breathing Four-chambered heart: Separates blood into oxygen-rich/oxygen- poor

Life cycle All have internal fertilization All have mammary glands 3 groups of Mammal life cycles: Placental: Marsupials: Monotremes:

Life cycle Placental: Develop inside mother’s body 95% of mammals are this Placenta—organ which allows for nutrients, oxygen, carbon dioxide and wastes to be exchanged

Life cycle Placental, cont.: Gestation period—time that embryo stays in the mother’s body Humans: 9 months, Elephants: 27 months, Mice: 21 days Mammary gland—young continue to feed by suckling Ex: humans, dolphin, elephant, most mammals

Life cycle Marsupials: Monotremes: Give birth to small, immature young that develop in a mother’s external sac (kangaroo) Mothers can move around and look for food while baby develops in the pouch Ex: kangaroo, koala, panda Monotremes: Mammals that give birth by laying eggs Incubate using her heat Ex: platypus