Mammals Test #5. Class Mammalia Have hair Most have an active metabolism Endothermic Efficient...
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Transcript of Mammals Test #5. Class Mammalia Have hair Most have an active metabolism Endothermic Efficient...
Mammals
Test #5
Class Mammalia
• Have hair
• Most have an active metabolism
• Endothermic
• Efficient respiratory and circulatory systems (4 chambered heart)
• Diaphragm helps with lungs
• Has mammary glands that produce milk
Reproduction
• Most are born and not hatched
• Internal fertilization
• Embryo develops in the uterus
• Uterus forms a placenta- where nutrients diffuse into the embryo’s blood
Brain
• Usually larger
• Capable of learning
• Care for young longer to teach them skills
• Needed for survival
Feeding
• Teeth come in a variety of shapes and sizes that are adapted to eat different kinds of foods– Incisors and canines-shearing or tearing– Premolars and molars- grinding
• Jaws that are different from reptiles
Major Orders of Mammals
1.Monotremes
2.Marsupials
3.Plancentals
Monotremes
• Comes from the greek word monos (single) trema (hole).
• Have a cloaca• Lack teeth as adults• Have a spur on the legs in the ankle
region that contains venom in a platypus.• Legs are on the sides of their bodies like
reptiles instead of underneath the body like most mammals.
Monotremes
• Platypuses and Echidnas (spiny ant eaters) – Only mammals that lay
eggs• Contain yolk to nourish
young
– Have hair and produce milk– No nipples-glands secrete
milk on stomach and the babies suck milk from fur
– Found in Australia and New Guinea
– Infant echidnas are known as puggles.
Marsupials
• Opossums, Kangaroos, Bandicoots, and Koalas– Born very early in development
and completes embryonic development while nursing
– Young are held in a pouch called a marsupium
• Example: The red kangaroo is the size of a honeybee at birth and is born 33 days after fertilization.
– It then crawls from the exit of the reproductive tract to the pouch
– Front limbs are more developed at the time of birth for climbing.
Marsupials
• Reproduction– Females have 2 vaginas that lead to two
separate uteruses– Females have a third canal that is used for
birth– Males have a pronged penis that is only used
to transfer sperm (not used for urination).– Both sexes have a cloaca
Placentals
• Gets it’s name from the placenta– Organ that transfers nutrients, oxygen, carbon
dioxide, and wastes between mother and embryo
– Allows the embryo to develop for a longer time period inside the mother
• Rats: a few weeks• Elephants: two years
12 Major Orders
• Insectivores (shrews, hedgehogs, moles)– Insect eaters– Have long narrow snouts and sharp claws for
digging
• Sirenians (Manatees, dugongs)– Herbivores– Live in rivers , bays and warm costal waters
scattered throughout most of the world– Slow, large, fully aquatic mammals
12 Major Orders
• Cetaceans ( Whales, dolphins)– Live underwater but must come to the surface to
breathe– Most live and breed in the ocean
• Chiropterans (Bats)– Winged mammals– Only mammals that can fly– 1/5 of all mammalian species– Eat mostly fruit, insects, or nectar but some feed on
the blood of other vertebrates
12 Major Orders
• Rodents (Mice, rats, voles, squirrels, beavers, porcupines, gophers, chipmunks, gerbils, prairie dogs, chinchillas)– Have a single pair of long, curved incisor teeth in
upper and lower jaws– Gnaw wood and other tough plant material
• Perissodactyls (horses, tapirs, rhinoceroses, and zebras)– Hofed animals with an odd number of toes on each
foot
12 Major Orders
• Carnivores (dogs, foxes, bears, racoons, walruses)– Stalk or chase prey by running or pouncing, then kill
with their sharp teeth or claws– Some eat plants and meat
• Artiodactyls (Cattle, sheep, goats, pigs, ibex, giraffes, hippopotami, camels, antelope, deer, gazelles)– Hoofed mammals have an even number of toes on
each foot– Mostly large grazing animals
12 Major Orders
• Lagomorphs (hares and rabbits)– Herbivores– Only have a pair of incisors in the upper jaw– Most have hind legs adapted for leaping
• Xentharthrans (sloths, anteaters and armadillos)– Have simple teeth without enamel– Some have no teeth at all
12 Major Orders
• Proboscideans (elephants)– Animals with trunks– Used to include mastodons and mammoths,
but today we only have African and Asian elephants
• Primates (lemurs, tarsiers, apes, gibbons, macques, humans)– Have a highly developed cerebrum and
complex behavior
Primates
• Early primates– Insectivores– Cretaceous period– Probably small and tree dwelling because they had
limber shoulders to swing on trees and hands to hang on branches
– Claws were replaced with nails– Sensitive, long fingers and toes– Eyes are close together in front of their face
(binocular vision)– Have depth perception that helps with swinging– Increased parental care
Primates
• 2 Sub orders– Prosimians “pre-
monkeys”• Lemurs, lorises, pottos,
and tarsiers• More like early primates
– Anthropoids• Monkeys, apes, and
humans• Fossils indicated they
were already established in Africa and Asia 40 mya
Prosimians
• Small
• Nocturnal primates with large eyes adapted to see in the dark
• Many have dog-like snouts
Anthropoids
• Anthropoid means “human-like primates”
• Branched into two based on evolutionary history
• New World monkeys and Old World monkeys
Monkeys
• Came to South America by raft (continents were closer together then) or by migration
New World Monkeys
• Arboreal-live and swing on trees– Have long prehensile
tails that coil around branches
– nostrils that open to the side
Old World Monkeys
• Ground dwelling and arboreal– Tail is not for swinging
and the nostrils open downward
– They also have tough seat pads on their behinds
– Most are diurnal (active during the day)
– Usually live in bands– Hominids are larger
Hominids (or “Great Apes”)
• Have 4 Genera
1. Hylobates (gibbons)
2. Pongo (orangutans)
3. Gorilla (gorillas)
4. Pan (chimpanzees) 5. Humans
Hominids• Are larger than monkeys• Long arms, short legs, and no
tails• All apes can swing from
branches– Only gibbons and orangutans
are arboreal• Gorillas and chimpanzees are
very social• Apes have proportionally
larger brains than monkeys• Apes behavior is more
adaptable• Can walk upright and grasp
with thumbs