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Biology - Chapter 33

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Herbivorous mammals, from cows to giraffes, eat plants that require thorough chewing ... large grazing animals: cattle, sheep, goats, hippos, giraffes, pigs ... – PowerPoint PPT presentation

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Title: Biology - Chapter 33


1
Biology - Chapter 33Mammals
  • Charles Page High School
  • Stephen L. Cotton

2
Section 33-1 Mammals
  • OBJECTIVES
  • Describe the characteristics of mammals.

3
Section 33-1 Mammals
  • OBJECTIVES
  • Discuss the importance of endothermy in the
    evolution of mammals.

4
Section 33-1 Mammals
  • The animals known as mammals vary greatly in
    appearance
  • from a tiny mouse to a huge elephant
  • flying in the air running along the ground
    swimming in the sea
  • but, Class Mammalia does have certain
    characteristics

5
Section 33-1 Mammals
  • Mammals are
  • endothermic animals (generate body heat
    internally)
  • experts at maintaining a constant body
    temperature, because of subcutaneous fat
  • also have sweat glands to help cool the body as
    it evaporates

6
Section 33-1 Mammals
  • Most mammals are viviparous- develop inside the
    mother for a time, and are then born alive
    however, a very few primitive varieties lay eggs
    (oviparous)
  • female mammals have mammary glands which produce
    milk for the young
  • have hair or fur at some time

7
Section 33-1 Mammals
  • Mammals have several kinds of teeth that either
    bite, chew, or grind food with efficient jaws
  • scientists use the teeth of a mammal to classify
    it into the different mammalian orders
  • Have well-developed breathing muscles, including
    a diaphragm that separates chest abdomen

8
Section 33-1 Mammals
  • A 4-chambered heart, consisting of 2 atria and 2
    ventricles, and a double loop circuit
  • one circuit moves blood to and from the lungs
  • the other circuit moves blood to and from cells
    in the rest of the body

9
Section 33-1 Mammals
  • Evolution of Mammals- the first mammals were
    small and probably resembled species of the tree
    shrews alive today
  • Figure 33-4, page 739
  • probably nocturnal, active mainly at night
    because they were endotherms

10
Section 33-1 Mammals
  • By the end of the Cretaceous Period, mammals had
    split into three groups
  • 1. Order Monotremata- called monotremes most
    primitive 6 species alive today examples are
    the duckbill platypus spiny anteater

11
Section 33-1 Mammals
  • 2. Order Marsupalia- the marsupials
  • includes opossums, kangaroos, wombats, and koalas
  • each of these species has a pouch (marsupium) in
    which its young live for a time to complete
    their development

12
Section 33-1 Mammals
  • 3. Placentals- composed of 16 orders
  • includes the mammals we are most familiar with,
    such as mice cats whales elephants and humans
  • hard to say exactly when each of these 3 groups
    appeared

13
Section 33-1 Mammals
  • We do know that the placental mammals experienced
    adaptive radiation in North America and Europe
  • Marsupials experienced adaptive radiation in
    Australia, South America, and Antarctica (which
    was a good deal warmer then than it is today)

14
Section 33-1 Mammals
  • Feeding- carnivorous mammals, such as cats and
    dogs, developed strong, sharp incisors and
    canines that are used for biting and ripping
    flesh use an up and down motion of the jaws
  • may also have sharp claws to grab prey bodies
    built for bursts of speed to chase prey

15
Section 33-1 Mammals
  • Herbivorous mammals, from cows to giraffes, eat
    plants that require thorough chewing
  • have evolved strong lips and flat-edged incisors
    that grasp and tear this tough vegetation
  • move their jaws side to side
  • However, it is still difficult to digest the
    plant cellulose

16
Section 33-1 Mammals
  • Many grazing animals (called ruminants) have a
    chamber in their digestive tract called the
    rumen, in which newly swallowed plant food is
    stored and processed for a time
  • the rumen contains thriving colonies of symbiotic
    bacteria that produce enzymes

17
Section 33-1 Mammals
  • After a time, the animal can then regurgitate the
    plant food from the rumen into its mouth
  • described as chewing their cud
  • the second time food is swallowed, it moves
    through the rest of the digestive system to
    complete digestion

18
Section 33-1 Mammals
  • Herbivores such as rabbits lack a rumen, but have
    a large dead-end sac called the cecum
  • contains some of the same types of bacteria that
    produce the digestive enzymes
  • ancestors of humans had a cecum, but is now
    shrunk into our appendix

19
Section 33-1 Mammals
  • Other mammals may drink blood, such as vampire
    bats
  • a chemical in saliva keeps the blood from
    clotting
  • Filter feeders- such as the giant blue whale- the
    teeth are modified into huge stiffened plates
    called baleen, which act like giant filters

20
Section 33-1 Mammals
  • Respiration- all mammals, even sea mammals, use
    lungs powered by two sets of muscles
  • 1. Chest muscles move ribs
  • 2. Diaphragm pulls downward to increase size of
    chest cavity and draw air in
  • many mammals use exhaled air over the vocal cords
    for sound

21
Section 33-1 Mammals
  • Internal Transport- 4-chambered heart pumps
    deoxygenated blood to the lungs, and after
    returning to the heart it pumps oxygenated blood
    to the body tissues
  • two circuits, one to lungs and the other to the
    body, efficiently transport gases and nutrients

22
Section 33-1 Mammals
  • Excretion- most highly developed kidneys of all
    vertebrates
  • kidneys also control the composition of body
    fluids
  • extract nitrogenous wastes from blood as urea
  • urea water excess salts urine flows
    through the ureters to the urinary bladder to
    store

23
Section 33-1 Mammals
  • Response- most highly developed brains of any
    animals
  • three parts of the brain
  • 1. Cerebrum- thinking, learning
  • 2. Cerebellum- coordination
  • 3. Medulla- regulate body functions such as
    breathing and heart rate

24
Section 33-1 Mammals
  • Mammals depend on highly developed senses- well
    developed sight, hearing, smell
  • most mammals do not see color well- except for
    apes, monkeys, and humans
  • probably because the first mammals were nocturnal
  • human ears not real sensitive

25
Section 33-1 Mammals
  • Dogs and bats hearing is great
  • human taste and smell is also not highly
    developed
  • Mammals depend on complex behavior for protection
  • herbivores able to run horns or hooves for
    defense band together into groups for protection

26
Section 33-1 Mammals
  • Movement- four limbs inherited from their
    ancestors
  • running mammals such as horses attain great
    speeds
  • climbing mammals such as monkeys prehensile tail
  • flying mammals bats
  • aquatic mammals like dolphins

27
Section 33-1 Mammals
  • Reproduction- the 3 groups of mammals vary
    greatly in their methods of reproduction
  • oviparous monotremes but still provide milk for
    nourishment
  • marsupials have limited yolk sac, so they are
    born early and crawl into a pouch (marsupium) to
    obtain the milk

28
Section 33-1 Mammals
  • In placental embryos, the egg membranes develop
    into tissues called the umbilical cord, which
    join with the mothers tissues at the placenta
  • the placenta allows the embryo to develop for a
    much longer time inside the mother
  • time is called gestation period

29
Section 33-2 Important Orders of Living Mammals
  • OBJECTIVES
  • Compare methods of mammalian reproduction.

30
Section 33-2 Important Orders of Living Mammals
  • OBJECTIVES
  • Identify the most important orders of placental
    mammals.

31
Section 33-2 Important Orders of Living Mammals
  • OBJECTIVES
  • Recognize the importance of mammals in the world.

32
Section 33-2 Important Orders of Living Mammals
  • Scientists use several traits to classify the
    mammals
  • structure of teeth
  • number and kinds of bones in the head
  • most important characteristic is the type of
    reproduction- we already learned the 3 types

33
Section 33-2 Important Orders of Living Mammals
  • Order Monotremata- the monotremes are egg-laying
    mammals, and are very rare
  • found in isolated parts of Australia and New
    Guinea
  • examples are the duckbill platypus (p.743) and
    spiny anteater (or echidna- p.746)

34
Section 33-2 Important Orders of Living Mammals
  • Order Marsupalia- the pouched mammals such as
    kangaroos and koalas are found in Australia
  • opossums are the only marsupials found in North
    America eat insects, birds
  • newborn are about the size of a bee- crawl into
    the pouch

35
Section 33-2 Important Orders of Living Mammals
  • Living placental mammals are placed into 16
    orders we will study 12 of the most important
  • in addition to having different reproductive
    habits, placental mammals have slightly higher
    metabolic rates
  • more abundant than marsupials

36
Section 33-2 Important Orders of Living Mammals
  • 1. Order Insectivora- the name means
    insect-eater
  • shrews, hedgehogs, moles
  • extremely high metabolic rate eat almost
    constantly to stay alive
  • biologists believe that the first mammals looked
    and behaved much like certain modern shrews

37
Section 33-2 Important Orders of Living Mammals
  • 2. Order Chiroptera- the different species of
    bats
  • some eat only insects
  • others eat only fruits
  • some feed on blood of other mammals (vampire
    bats)
  • echolocation-navigate at night

38
Section 33-2 Important Orders of Living Mammals
  • 3. Order Edentata- the name means without teeth
    even though some of them have teeth
  • sloths (South American- slow moving, hang upside
    down), anteaters (long tongue, tapered snout
    powerful legs to rip open ant nests), and
    armadillos

39
Section 33-2 Important Orders of Living Mammals
  • 4. Order Rodentia- many amusing animals, and some
    quite destructive
  • mice rats squirrels beavers porcupines, and
    gophers
  • all have 2 long front teeth that continually
    grow, thus they wear them down by gnawing

40
Section 33-2 Important Orders of Living Mammals
  • Most rodents are small, and have a short
    gestation period
  • rats and mice are adaptable animals that eat a
    wide variety of foods
  • long ago, these rodents moved in with humans and
    have traveled with us the world over

41
Trees damaged by beavers.
42
Trees damaged by beavers.
43
Section 33-2 Important Orders of Living Mammals
  • 5. Order Lagomorpha- familiar rabbits and hares
  • closely resemble rodents because they have sharp
    front teeth and eat plant material
  • gestation period is short, and the number of
    offspring is high
  • compete with us for food

44
Section 33-2 Important Orders of Living Mammals
  • 6. Order Carnivora- are meat eaters- dogs, cats,
    wolves, bears, weasels, hyenas, seals
  • most are terrestrial, stalking and chasing their
    prey
  • seals and walruses had at one time land
    ancestors, but have since returned to the ocean

45
Section 33-2 Important Orders of Living Mammals
  • 7. Order Cetacea- the truly aquatic mammals-
    whales, dolphins, and porpoises
  • still breathe air- have lungs and a circulation
    designed to permit long, deep dives
  • have a layer of subcutaneous fat (blubber) to
    keep warm

46
Section 33-2 Important Orders of Living Mammals
  • 8. Order Sirenia- strange aquatic animals related
    to elephants
  • peaceful,slow-moving herbivores in rivers and
    streams of Africa, South America, and Florida
  • the manatee (sea cow) is often injured by
    careless boaters

47
Section 33-2 Important Orders of Living Mammals
  • 9. Order Artiodactyla- large grazing animals
    cattle, sheep, goats, hippos, giraffes, pigs
  • original 5 toes on each foot have been reduced to
    2
  • called even-toed ungulates (hoofed mammals)

48
Section 33-2 Important Orders of Living Mammals
  • 10. Order Perissodactyla- horses, zebras, tapirs,
    and rhino
  • these are the odd-toed ungulates
  • contains many grazing animals with habits similar
    to those of the even-toed ungulates

49
Section 33-2 Important Orders of Living Mammals
  • 11. Order Proboscidea- mammals with trunks- the
    great elephants
  • formerly included mammoths and mastodons
  • today, 2 species the Indian elephant and African
    elephant, both in danger of extinction

50
Section 33-2 Important Orders of Living Mammals
  • 12. Order Primates- which includes our own
    species (humans), and is closely related to
    ancient insectivores
  • most highly developed cerebrum, and most
    complicated behaviors

51
Section 33-2 Important Orders of Living Mammals
  • The most primitive living primates, the lemurs,
    are small tree dwellers two other main branches
    are monkeys and apes
  • Very early in their evolutionary history,
    primates as a group were split apart by the
    moving continents

52
Section 33-2 Important Orders of Living Mammals
  • One branch, the New World monkeys, includes the
    squirrel monkey and spider monkey
  • these live almost entirely in trees
  • have long arms for swinging, and a long
    prehensile tail for grasping

53
Section 33-2 Important Orders of Living Mammals
  • The other branch, the Old World monkeys, include
    chimpanzees, gorillas, and the ancestors of
    humans
  • many still spend much of their time in trees, but
    they all lack prehensile tails

54
Section 33-2 Important Orders of Living Mammals
  • How Mammals Fit Into the World
  • evolved from early reptile ancestors during the
    Mesozoic Era about 200 million years ago
  • herbivores are major plant consumers- grazing
    zebras, reindeer herds, oxen

55
Section 33-2 Important Orders of Living Mammals
  • The herbivores are food for the carnivores-
    lions leopards wild dogs wolves
  • bats eat large numbers of mosquitoes
  • squirrels eat nuts and seeds
  • domesticated animals for work horses oxen mules

56
Section 33-2 Important Orders of Living Mammals
  • Many of these animals also provide food in the
    form of meat and dairy products
  • dogs are used to hunt, helping humans find food
  • But, some mammals have a negative impact on human
    life

57
Section 33-2 Important Orders of Living Mammals
  • Carnivores prey on domesticated animals
  • rodents such as rats and mice damage crops, eat
    stored food
  • some mammals carry diseases, such as rats that
    harbor fleas that spread the plague

58
Section 33-2 Important Orders of Living Mammals
  • Dogs, squirrels, other wild animals that transmit
    the virus for rabies
  • elephants destroy trees as they feed
  • overgrazing by cattle turns land into a dust
    bowl beavers flood areas
  • Humans- good or bad influence?
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