Non-vertebrate Chordates, Fishes, and Amphibians

1
Non-vertebrate Chordates, Fishes, and Amphibians

• Chapter 30

2
Phylum Chordata

• Contains three sub-phyla
• Vertebrata
• Urochordata
• Cephalochordata
• All chordates at some point in their life span
  must possess four characteristics

3

1. A hollow, dorsal nerve cord
2. A notochord (supporting rod)
3. Pharyngeal gill slits
4. A tail that extends beyond the anus

4
Urochordates

• Also known as the tunicates or sea squirts
• Basically a sack with two siphons.

5
Cephalochordates

• Examples amphioxus and lancelets

6
Vertebrates

• Most numerous chordates
• Anterior, large brain
• Jointed internal skeleton
• Usually two pairs of appendages and some type of
  tail
• Closed circulatory system
• Gills or lungs and a chambered heart

7
7 major classes of vertebrates

• Jawless fishes, cartilaginous fishes, bony
  fishes, amphibians, reptiles, birds, mammals
• Ectotherms cold-blooded body temp changes
  with the environment.
• Endotherms warm blooded body tem remains
  fairly constant

8
FISH or FISHES

• Both words can be used for the plural of a fish.
• Fishes is often used when talking about
  taxonomy or classification.

9
1. Class Agnatha

• jawless fishes
• Most primitive vertebrates
• No scales nor fins
• Cartilage skeleton
• No jaws
• Both fresh and salt water varieties.
• examples lampreys and hagfish

10
LAMPREY

• Both fresh and salt water. (parasitic)
• Possess a tongue with teeth that gnaw a hole in
  its victim then sucks out the blood.
• Can be harmful to fish populations.

11
HAGFISH

• Only found in salt water. scavengers
• Also known as slime eels
• Produce great amounts of slime for defense. Can
  tie themselves in a knot

12
2. Class Chondricthyes

• Chondros (Gr. Cartilage)
• Ichthys (Gr. Fish)
• Mostly marine
• 2 chambered heart
• Movable upper and lower jaws
• ex. Sharks, skates, and rays

13
Skates and rays

• Flattened body (countershading)
• Eat worms, mollusks, and other invertebrates
• Can be specialized for defense
• Stingers
• Electric rays

14
SHARKS

• Internal fertilization.
• Viviparous live birth
• Need to be constantly swimming to keep water
  moving over the gills
• Very highly developed sense of smell.
• Covered with sandpaper-like scales called placoid
  scales.

15
Medicinal uses

• Currently shark cartilage is being tested as a
  possible cure for cancer.

16
3. Class Osteicthyes

• Osteo- Gr. Meaning bone
• Known as the bony fishes
• Largest class of vertebrates.
• Vary in size, shape, and structure.
• Complex nervous system (lateral lines)
• Very specialized.
• Electric eel, pufferfish, angler fish, butterfly
  fish

17
Wide Variety
18
Structure of a bony fish

• Usually four pairs of gills covered by a bony
  flap (operculum)
• 2 chambered heart
• Many have scales and fins
• Swim bladder gas-filled sac which is used for
  buoyancy (maintain depth)

19
Reproduction

• External.
• A female will lay upto 500,000 eggs.
• The male usually swims over the eggs depositing
  milt (sperm containing fluid)

20
The Coelacanth

• A special fleshy-lobed finned fish thought to be
  extinct.
• 1938 one was caught off the southern coast of
  Africa.

21
4. Class Amphibia

• from water to land
• Reproduction and development must take place in
  or near water.
• Thin moist skin
• Two pairs of limbs, one pair of nostrils
• 3 chambered heart
• Young show a distinct larval form.

22
Examples
axolotl
mudpuppy
Frogs
salamanders
23
Frog anatomy and function

• Large powerful hind legs for jumping.
• 2 large movable eyes
• Tympanic membrane
• 3 eyelids
• Upper
• Lower
• Nictitating membrane (transparent used for
  underwater sight.

24
digestion

• Large mouth.
• Long sticky spade-shaped tongue
• Teeth along upper jaw.
• A pair of vomerine teeth used to hold prey in
  mouth
• Esophagus...stomach...small intestine(site of
  absorption)..large intestine...cloacaanal
  opening.

25
Circulatory system

• Oxygenated blood enters left atrium from lungs.
  Deoxygenated blood enters right atrium from rest
  of body.
• Both empty into ventricle where a mixture of
  oxygen and non-oxygen blood is pumped out

26
Respiratory system

• Tadpoles use gills to breathe.
• Adult frog uses three structures for respiration.

skin
Lungs
Lining of the mouth
27
Nervous system

• Possess both a cranial and peripheral nervous
  system
• Multi-lobed brain
• Olfactory(smell)
• Optic(sight)
• Cerebrum(voluntary muscles)
• Cerebellum(coordination)
• Medulla(involuntary muscle action)

28
Excretory system

• CO2 excreted through the skin, other wastes
  filtered through the kidneys.
• Urine is stored in urinary bladder then passed
  into cloaca and out of the body.

29
Reproduction

• External fertilization
• amplexus male grasps female, eggs are released
  then quickly fertilized by the male.

30
Order Urodela

• Salamanders and newts
• Long bodies and tails
• Live in dark, moist places.

31
Orders Anura Apoda

• ANURA
• Frogs and toads

• APODA
• Caecilians
• Legless amphibians

32
Assignment

• Pages 793-794
• 1-10, 14, 17, 18, 20, 23, 24, 28
• Page 795 1-10