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Nonvertebrate Chordates, Fishes, and Amphibians

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... nerve cord; a notochord; pharyngeal pouches; and a tail that extends ... Notochord: long supporting rod that runs through the body just below the nerve cord ... – PowerPoint PPT presentation

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Title: Nonvertebrate Chordates, Fishes, and Amphibians


1
Nonvertebrate Chordates, Fishes, and Amphibians
  • Unit VI
  • Chapter 30

2
The Chordates
  • A chordate is an animal that has, for at least
    some stage of its life, a dorsal, hollow nerve
    cord a notochord pharyngeal pouches and a tail
    that extends beyond the anus
  • Dorsal hollow nerve cord runs along the back
    part of the body with nerves that branch and
    connect to organs
  • Notochord long supporting rod that runs through
    the body just below the nerve cord
  • Pharyngeal pouches found in the pharynx region
    may develop into gills
  • Post anal tail contains bone and muscle and is
    used in swimming by aquatic species

3
Chordate Characteristics
4
Most Chordates are Vertebrates
5
Nonvertebrate Chordates
  • The two groups of nonvertebrate chordates are
    tunicates and lancelets
  • Both are soft-bodied marine organisms

6
Tunicates
  • Tunicates are filter feeders that exhibit all of
    the chordate characteristics as larva but not as
    adults

7
Lancelets
  • Lancelets are small, fishlike creatures that
    thrive on the sandy ocean floor
  • An adult lancelet has a head region that contains
    a mouth

8
Fishes
  • Fishes are aquatic vertebrates that are
    characterized by paired fins, scales, and gills

9
The Rise of Modern Fishes
  • While most early jawed fishes disappeared, they
    left behind two major groups that continued to
    evolve and still survive today
  • Cartilaginous fishes (sharks rays)
  • Boney fishes (modern fishes)

10
Fish Anatomy
11
Form Function in Fishes
  • Adaptations to aquatic life include various modes
    of feeding, specialized structures for gas
    exchange, and paired fins for locomotion

12
Fish Feeding
  • Fish can be herbivores, carnivores, parasites,
    filter feeders, and detritus feeders.
  • The diagram below highlights some internal organs
    important during the fishs digestion

13
Fish Respiration
  • Most fishes exchange gases using gills located on
    either side of the pharynx
  • Oxygen-rich water is pulled in through the mouth
    and over the gill filaments
  • Oxygen-poor water is pushed out through the
    openings in the sides of the pharynx
  • Some fishes, including the lungfish, have a
    lung-like adaptation that allows them to survive
    in oxygen poor water

14
Fish Circulation
  • Fishes have closed circulatory systems with well
    developed heart that pumps blood around the body
    in a single loop
  • From the heart to the gills
  • From the gills to the rest of the body
  • Back to the heart

15
Fish Circulatory System
16
Fish Excretion
  • Fishes rid themselves of nitrogenous wastes in
    the form of ammonia
  • Kidneys help fishes control the amount of water
    in their bodies

17
Fish Response
  • Fishes have well-developed nervous systems
    organized around a brain which has several parts
  • Olfactory bulb sense of smell
  • Cerebrum voluntary activities of body
  • Optic lobe eye function
  • Cerebellum coordinates body movement
  • Medulla oblongata controls internal organ
    functions
  • Spinal cord
  • Most fishes can detect gentle currents and
    vibrations in the water with a sensitive receptor
    called the lateral line system

18
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19
Fish Movement
  • The streamlined body shapes of most fishes help
    to reduce the amount of drag (friction) as they
    move through the water
  • Fins assist in movement
  • Many bony fishes have an internal, gas-filled
    organ called a swim bladder that adjusts their
    buoyancy
  • Because their body tissues are more dense than
    water, sinking would be an issue without the swim
    bladder

20
Fish Reproduction
  • Fishes whose eggs hatch outside the mothers body
    are oviparous
  • As the embryos develop, they obtain food from the
    yolk in the egg
  • Fishes whose eggs stay inside the mothers body
    are ovoviviparous
  • Egg yolk is used for nourishment
  • Fishes whose embryos stay in the mothers body
    and get nourishment from the mother are
    viviparous
  • These fishes are born alive

21
Groups of Fishes
  • All living fishes can be classified into three
    groups
  • Jawless fishes (class Agnatha) have no true
    teeth or jaws
  • Lampreys and hagfishes
  • Cartilaginous fishes (class Chondrichthyes)
    skeletons are built entirely of cartilage, not
    bone
  • Sharks, rays, skates
  • Bony fishes (class Osteichthyes) skeletons are
    made of hard, calcified bone
  • Most other fishes

22
Amphibians
  • An amphibian is a vertebrate that, with some
    exceptions, lives in water as a larva and on land
    as an adult, breathes with lungs as an adult, has
    moist skin that contains mucus glands, and lacks
    scales and claws
  • Amphibian adaptations for life on land include
  • Limb bones become stronger
  • Lungs and breathing tubes
  • Sternum to protect internal organs

23
Amphibian Feeding
  • Tadpoles are filter feeders whereas adult
    amphibians are carnivorous
  • Many have long, sticky tongues used to capture
    insects
  • Digestion involves food traveling from the mouth
    down the esophagus into the stomach
  • From the stomach into the small intestine
  • From the small intestine to the large intestine
  • From the large intestine into the cloaca (the
    pathway for waste to leave the body

24
Frog Digestive System
25
Amphibian Respiration Circulation
  • In larval amphibians, gas exchange occurs through
    the skin and gills
  • Lungs replace gills in adult amphibians but
    some gases continue to diffuse through the skin
  • In adult amphibians, the circulatory system forms
    a double loop
  • 1st loop carries oxygen-poor blood from the heart
    to the lungs and skin and takes oxygen-rich blood
    from the lungs and skin back to the heart
  • The 2nd loop transports oxygen-rich blood from
    the heart to the rest of the body and oxygen-poor
    blood from the body back to the heart

26
Frog Circulatory System Heart
  • The amphibian heart has 3 chambers
  • Left atrium, right atrium, and ventricle

27
Amphibian Excretion Reproduction
  • Amphibians have kidneys that filter wastes from
    the blood
  • Amphibian eggs must be kept moist to avoid drying
    out
  • External fertilization
  • Eggs are abandoned after the frogs lay them
  • Offspring metamorphosize from tadpoles into frogs

28
Amphibian Movement
  • Amphibian larvae move like fishes
  • Adult salamanders have legs that stick out
    sideways walking involves moving the body into
    an S-shaped curve
  • Frogs and toads have well-developed hind limbs
    that enable them to jump
  • Tree frogs have disks on their toes that serve as
    suction cups for climbing

29
Amphibian Response
  • The brain of an amphibian is very similar to that
    of a fish
  • They have well developed nervous systems
  • They hear through tympanic membranes (eardrums)
    located on each side of the head

30
Groups of Amphibians
  • Salamanders
  • Frogs Toads
  • Caecilians

31
Amphibian Concept Map
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