Phylum Chordata

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Phylum Chordata

• Charactertistics of Chordates
• All chordates possess a notochord.
• Long felxable rod between gut nerve cord
• Runs most of length of animal
• Possess a dorsal, hollow, nerve cord
• Possess pharangeal slits
• Muscular post-anal tail

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Urochordates

• Subphylum Urochordata
• Commonly called turnicates
• Sessile marine animals as adults - Motile as
  larva
• Larva possess a clear notochord which is less
  evident in adults
• Filter feed through use of siphon

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Subphylum Cephalochordata

• Commonly known as lancets
• Have all features of the ideal chordate
• Bury selves in sand, and filter-feed through mouth

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Phylum Chordata The Vertebrates

• Subphylum Vertebrata
• Seven extant classes
• First 3 commonly called fishes
• Remaining 4 called tetrapods (4 feet)
• All possess some form of segmented vertebra

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Class Agnatha

• Commonly known as Jawless Fish
• Include hagfish Lampreys
• Lack paired appendages
• Lack bony skeleton
• Lack jaws
• Usually have circular sucking mouthparts
• Lampreys parasitize other fish

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Lampreys
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Hagfish
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Class Chondrichthyes

• Include sharks skates, rays
• Very successful class
• Called cartilagenous fishes because skeleton is
  cartilage not bone
• Approx. 750 species
• Have paired appendages
• Many have acute senses
• Sharks have a lateral-line system
• Allows shark to detect water pressure changes

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Sharks
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Noteworthy Shark Species
Great White Shark
Tiger Shark
Whale Shark
Bull Shark
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Rays Skates
Southern Stingray
Manta Ray
Skates
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Class Osteichthes

• Called Bony fish
• Most diverse of all fish
• Have skeleton made of bone
• Have Cycloid Scales
• Have paired fins
• Allowed evolution of 4 limbed amphibians
  (tetrapods)
• Possess scales for protection
• Have bony flap called operculum
• Allows water to be drawn over gills by fins
• Have Swim bladder
• Gas content can be manipulated allowing for
  changes in bouyancy

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Bluefish
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Class Amphibia

• First vertebrates to inhabit land
• Most are 4 limbed (tetrapods)
• Include frogs, salamanders caecilians
• Have 3 chambered heart
• Have more complicated gas exchange organs (often
  a combination of lungs, gills and skin)

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Order Urodela(Salamanders Newts)

• Urodela ("tailed ones" - Salamanders)
• More dependent on water
• Many species possess gills as adults

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Class Apoda ("tail-less ones" - Frogs toads)

• Have more developed lungs than salamanders
• Lack a diaphragm must swallow air
• Most diverse and common of amphibians.
• Toads are the first amphibians to evolve
  keratinized skin.
• This waterproofs the skin preventing water loss
• Toads must still return to water to lay eggs.

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Common North American Frogs
North American Toad
Green Frog
Bullfrog
Poison Arrow Frog
Leopard Frog
Peepers
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Caecilia ("legless ones")
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Reproduction

• Lack internal fertilization amniotic eggs
• Reproduction must occur in H2O
• Most species undergo metamorphosis
• Larval stage (tadpole) is usually an aquatic
  herbavore
• Lacks legs, respiration is through gills
• Develops into tetrapod adult (usually carnivorous)

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Class Reptilia

• Includes lizards, snakes, turtles, and
  crocodilians
• Over 7000 species
• Possess several advanced features over amphibians
• Most adaptations towards independence from H2O
• Possess scales containing keratin
• Keratin is a waterproofing protein which prevents
  water loss in an organism
• Possess an amniotic egg.
• Prevents water loss of embryo. Allows for eggs
  to be laid on dry land
• Combined with internal fertilization, allows
  reptiles to reproduce independently of water
• Reptiles are "cold blooded" or ectotherms
• Cannot internally regulate body temperatures
• Reptiles can regulate body temperatures
  behaviorally (eg. Basking or swimming)
• Nutritional requirements are lower than warm
  blooded animals

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The Amniotic Egg
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Modern Reptiles

• Order Chelonia (Turtles Tortoises)
• Inhabit aquatic and terrestrial environment.
• Are herbavores, carnivores, and omnivores
• Characterized by possessing a hard dorsal shell
• Made from bone, extensions of backbone and rib
  cage

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Common North American Turtles
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Order Squamata

• Order Squamata (Lizards Snakes)
• Most numerous diverse of the reptiles
• Most relatively small Although monitors and their
  relatives can grow to 6' in length
• Herbivores, carnivores omnivores
• Most able to exhibit some form of hibernation

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Noteworthy Lizards
Komodo Dragon
Eastern Fence Lizard
Anole
Leopard Gecko
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North American Snakes
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Order Crocodilia (Crocodiles, Alligators,
Caimans)

• Largest extant reptiles can grow to over 15 and
  weigh over a ton
• Primarily aquatic they are true reptiles
• Inhabit warm, tropical climates
• Order most closely related to the dinosaurs

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Crocodilians
Crocodile
Alligator
Gavail
Caiman
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Class Aves(The Birds)

• Evolved from dinosaurs during Mezozoic era.
• Aminotic eggs and scales on legs reminants of
  reptilian origins
• Almost all adaptations of these animals are made
  for flight.
• Presence of feathers
• Made of keratin
• Can be used for insulation and flight
• Forelimbs developed into wings
• Honeycombed, light bone structure

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Feathers
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Beak Types

• Absence of some organs
• Females usually have 1 ovary
• Absence of teeth lighten head
• Replaced by gizzard in abdomen beak
• Beak made of keratin
• Proven very adaptable structure, having a variety
  of shapes for differing diets

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Reproduction

• Reproduction is through hardened amniotic eggs
• Since birds are endothermic, these must be kept
  warm by parents
• This behavior called brooding

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Birds Feet
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Modern Birds

• Over 8600 species 20 orders of birds
• Classified into 2 general groups
• Flightless species including ostrich, emus,
  kiwis are known as ratites
• Lack sternal keel on breastbone
• Lack strong breast muscles needed for flight

Ostrich A ratite
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Modern birds contd.

• Other species capable of supporting flight called
  carinates
• 60 are "perching birds" called passeriforms
• Possess a sternal keel on breastbone
• Support strong breast muscles required for flight

The sparrow A passeriform carinate
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Class mammalia

• Approx. 4500 species of mammals
• Evolved from mammal-like reptiles called
  therapsids in the triassic period
• Diversified greatly following the extinction of
  dinosaurs
• Mammilian Characteristics
• Have Hair
• Made of keratin
• Aids in maintaining body temperature
• Endothermic
• Maintain body temperature internally
• Have efficient respiratory system including a
  diaphragm
• Efficient circulatory system with a 4-chambered
  heart
• Most possess placentas and give birth to live
  young
• Have mammary glands to produce milk for offspring
• All show parental care of offspring
• Have largest brains of all vertebrates
• Have differentiated teeth
• Unlike earlier vertebrates, several different
  teeth can exist in mammal jaws
• Eg. The molars incisors in the human jaw

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General Types of Mammals

• Monotremes
• Early branch from reptilian line
• Include platypuses echidnas (spiny anteaters)
• Only group to lay eggs (reptilian in structure)
• Have mammary glands to feed young

Duck Billed Platypus
Echidna
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Marsupials

• Include opossums, kangaroos koalas
• Mostly found in Australia New Zealand
• Were isolated in these landmasses when the
  continents separated and did not evolve li the
  same way placental mammals did
• Do not develop placentas
• Give birth to young very early
• Fetuses complete development in pouch called
  marsupium
• Mammary glands found in pouch nourish young until
  development is complete

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Examples of marsupials
Koala
Opossum
Kangaroo
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Placental Mammals

• Complete embryonic development in uterus
• Joined to parent by organ called placenta
• Only "disposable" mammal organ
• Discarded following birth
• Exchanges gasses, nutrients waste between
  mother and fetus

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Common North American Mammals 1
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Common North American Mammals 2