Phylum Chordata

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Phylum Chordata
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Phylum Chordata

• They have 4 main characteristics that they must
  have at some time in their development.
• dorsal, hollow nerve cord
• notochord- long supporting rod runs near nerve
  cord
• pharyngeal pouches- paired structures in the
  throat region
• a tail that extends beyond the anus

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Sub-Phylum Vertebrata

• A chordate that has a strong supporting structure
  Vertebral Column or Backbone.
• Dorsal hollow nerve cord -aka Spinal cord
• The front of the spinal cord grows into the brain
• Backbone made of individual segments called
  vertebrae.
• Endoskeleton-supports and protects the animals
  body.
• Major groups-Fishes, Amphibians, Reptiles, Birds,
  and Mammals

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Fishes

• Aquatic vertebrates
• fresh and marine waters
• Fish were the first vertebrates to evolve
• About 510 million years ago
• Not like the fish we see today.
• Characteristics (there are some exceptions)
• Paired fins -movement
• Scales protection
• Gills gas exchange
• Ectotherms

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Fishes

• Three groups of fish
• Agnathans
• Jawless fishes (Lampreys and Hagfish)
• Lack true teeth and jaws
• Chondrichthyes
• Cartilaginous fishes (Sharks, rays, etc.)
• Skeletons are built entirely of cartilage, not
  bone.
• Osteichthyes
• Bony fishes
• Skeletons are made of hard, calcified tissue
  called bone.

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Fishes

• Feeding
• Herbivores, carnivores, parasites, filter
  feeders, and detritus feeders.
• They have a 2-opening digestive track with
• Mouth, esophagus, stomach, pyloric ceca,
  intestine, anus, also have a liver, and pancreas
• Respiration
• Most fishes exchange gas through gills located on
  either side of the pharynx
• Water passes over the gills and O2 and CO2 are
  exchanged between the water and blood
• A few fishes have lungs

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Fishes

• Circulation
• Closed circulatory system with a four-chambered
  heart that pumps blood in a single loop
• Heart Gills Body Heart
• Excretion
• Waste in the form of ammonia
• Some wastes diffuse through gills (CO2) and
  others are removed by the kidneys
• Response
• Well-developed nervous system
• Highly developed sense organs
• Lateral line system
• Sensitive receptor system that enables fish to
  detect gentle currents and vibrations in the
  water

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Fishes

• Movement
• Move by alternately contracting paired sets of
  muscles on either side of the backbone.
• Creates a series of S-shaped curves
• Use of fins for direction
• Swim bladder gas-filled organ that helps fish
  stay afloat.
• Reproduction
• External and internal fertilization depends on
  the species

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Amphibians

• About 4000 living species
• First seen about 360 million years ago
• Gave rise to all other land vertebrates
• Amphibian means Double Life
• Live in water and on land
• Must return to water to reproduce
• Characteristics
• Lives in water as a larva
• Lives on land as an adult
• Moist skin that contains mucus glands
• Lacks scales and claws
• Ectotherms

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Amphibians

• Three groups of Amphibians
• Salamanders
• Long bodies and tails
• Most have 4 legs
• Carnivores
• Found in moist woods
• Tunnel under rocks and rotting logs
• some keep their gills
• Frogs and Toads
• They can jump
• Frogs have longer legs than toads
• Frogs found more in water areas and toads in
  moist woods and deserts
• Adults lack tails
• Caecilians
• Legless animals that live in water or moist soil
• Feed on small invertebrates

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Amphibians

• Feeding
• Tadpoles are filter feeders or herbivores
• Adults are carnivores
• Complete 2-opening digestive track
• Mouth, esophagus, stomach, small intestine, large
  intestine, cloaca, also have a liver, gallbladder
  and pancreas
• Respiration
• Larval forms- gas exchange through skin and gills
• Adults- gas exchange through lungs and skin
• Salamanders do not have well developed lungs
• Gas exchange through linings in mouth
• Circulation
• Closed circulatory system with a heart that pumps
  blood in a double loop
• Heart Lungs/Skin Heart Body Heart

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Amphibians

• Excretion
• Kidneys that filter waste from the blood and pass
  out the cloaca
• Kidneys Ureters Urinary bladder Cloaca
  Outside
• Response
• Well developed nervous system and sensory systems
• Large and moveable eyes
• Hear through tympanic membranes
• Membrane vibrates sending sound to the brain
• Many larva and adult forms have lateral line
  system to detect water movement

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Amphibians

• Movement
• Larvae often move like fish wiggling their
  bodies and using their tail
• Adults use front and back legs for walking,
  running, jumping
• Reproduction
• Internal and external fertilization
• Shell less eggs
• Eggs are laid in wateras many as 200

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Reptiles

• About 7000 living species
• First seen about 350 million years ago
• More common around 300 million years ago
• Found all over earth, except very cold places
• Characteristics
• Dry, scaly skin
• The tough skin does not grow, it needs to be shed
  periodically
• Lungs
• Terrestrial eggs
• Well developed skull
• Backbone and tail
• Four limbs (except snakes)
• Ectotherms

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Reptiles

• Four surviving groups of reptiles
• Lizards and snakes
• Lizards
• Legs, clawed toes, external ears, movable eyelids
• Snakes
• Lack limbs
• Crocodilians
• Alligators, Crocodiles, etc.
• Fierce carnivores
• Only freshwater, except crocodiles that may live
  in either salt water or freshwater
• Turtles and tortoises
• Turtles live in water
• Tortoises live on land
• Have a shell that is built into their skeleton
• Lack teethhave bony ridges that cover upper and
  lower jaws
• Tuatara
• Found only on a few small islands off of New
  Zealand
• Resemble lizards, except they lack external ears,
  and retain primitive scales
• Have a third eye on top of head.function is
  still unknown

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Reptiles

• Feeding
• Herbivores, and carnivores
• They have a two-opening digestive track
• Respiration
• Lungs for respiration
• Lungs are spongy providing more gas exchange
  than amphibians
• Circulation
• Have a closed circulatory system
• Efficient double-loop
• Heart lungs heart body heart
• Have two atria and either one or two ventricles
• Most reptiles have one ventricle, however
  crocodiles and alligators have the most developed
  hearts with two ventricles.

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Reptiles

• Excretion
• Kidneys filter blood and produce urine
• Some reptiles have a urinary bladder
• Urine contains either ammonia or uric acid
• Response
• Similar brain to that of an amphibian
• Except cerebrum and cerebellum are larger
  compared to the rest of the brain
• Complex eyes that can see color well
• Good sense of smell
• Most have a pair of sensory organs in the roof of
  the mouth that can detect chemicals
• Simple ears with external ear drums
• Some snakes can detect body heat

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Reptiles

• Movement
• Reptiles with legs have larger and stronger limbs
  that enable them to walk, run, burrow, swim, or
  climb
• Limbs are rotated further under the body allowing
  them to carry more body weight
• Legs and feet of many aquatic turtles have
  developed into flippers
• Reproduction
• All reproduce by internal fertilization
• Male deposits sperm inside the female
• Most lay eggs that develop out side the body
• The shell and membranes of the egg help create a
  protected environment for the embryo to develop
  with out drying out
• Called an amniotic egg

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Birds

• Nearly 10,000 bird species today
• Reptile like animals
• First seen 150 million years ago
• Archaeopteryx
• Characteristics
• Endotherms
• Maintain a constant body temperature
• Hollow bones
• Outer covering of feathers
• Made mostly of protein
• Help birds to fly and maintain temp.
• Two legs that are covered with scales
• Used for walking or perching
• Modified front limbs for flying

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Birds

• Over 30 different groups
• Largest group is the Passerines
• Over 5,000 species
• Perching birds
• Larks, sparrows, finches
• Some other groups
• Pelicans and their relatives
• Pelicans, boobies, etc.
• Parrots
• Macaws, lovebirds, cockatoos, etc.
• Birds of prey
• Condors, hawks, owls, eagles, etc.
• Cavity-nesting birds
• Woodpeckers, toucans, etc.
• Herons and their relatives
• Storks, spoonbills, cranes, herons, etc.
• Ostriches and their relatives
• Ostriches, emus, etc.

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Birds

• Feeding
• The beak is adapted to the type of food they eat.
• Complete two-opening digestive track from mouth
  to cloaca
• Lack teeth
• Respiration
• One-way flow of air
• Allows for constant exposure of the lungs to
  oxygen-rich air
• Have air sacs in the body cavity and bones
• Circulation
• Closed circulatory system with a double loop
  system
• Four-chambered heart
• Two atria and two ventricles
• Complete separation of oxygen-rich and
  oxygen-poor blood

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Birds

• Excretion
• Similar to reptiles
• Nitrogenous waste is removed from blood by the
  kidney, converted to uric acid and deposited in
  the cloaca
• Most water is reabsorbed in the cloaca leaving
  uric acid crystals in a white pasty form
• Response
• Well developed sense organs
• Well developed eyes
• See color very well
• Hear very well
• Brain that can quickly interpret and respond to a
  lot of incoming signals

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Birds

• Movement
• Some birds cannot fly
• They walk, run, or swim
• Large chest muscles that aid in flying
• Reproduction
• Both male and female reproductive tracks open
  into the cloaca
• Organs often shrink in size when not breeding
• Amniotic eggs
• Similar to reptiles, but have a hard outer shell

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Mammals

• Nearly 4500 species today
• First seen 220 million years ago
• Characteristics
• Endotherms
• Maintain a constant body temperature
• Have hair
• Nourish their young with milk
• Breath air
• Four-chambered heart

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Mammals

• Three main groups of mammals
• Differ in means of reproduction and development
• Monotremes
• Three species exist (duckbill platypus, and two
  species spiny ant eaters)
• Lay eggs
• Have cloaca
• Marsupials
• Bear live young that complete their development
  in a pouch
• Kangaroos, koalas, wombats
• Placentals
• Nutrients, oxygen, carbon dioxide, and wastes are
  exchanged between embryo and mother through the
  placenta
• Humans, dogs, cats, elephants, etc

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Mammals

• Feeding
• As mammals evolved, the form and function of
  their jaws and teeth became adapted to eat
  different types of food
• Herbivores
• Jaws move from side to side
• Carnivores
• Jaws move up and down
• Respiration
• Lungs
• Diaphragm
• Muscle that pulls the bottom of the chest cavity
  downward which increases volume
• Circulation
• Closed, double-loop circulatory system
• Four-chambered heart

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Mammals

• Excretion
• Highly developed kidneys that extract nitrogenous
  waste from the blood in the form of urea
• Urea, with other wastes, and water combine to
  form urine (Pee)
• Urine is stored in a urinary bladder until it is
  eliminated
• Response
• Have the most highly developed brain of any other
  animal
• Highly developed senses
• Taste
• Smell
• Touch
• Hearing
• Sight

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Mammals

• Movement
• Evolved a variety of adaptations that aid in
  movement
• Backbone that flexes both vertically and side to
  side
• Shoulders and pelvic bones became more
  streamlined and flexible
• Allows them to
• Run, walk, climb, burrow, hop, pounce, swing,
  fly, leap, and swim
• Reproduction
• Internal fertilization
• Males deposit sperm inside the female
  reproductive track
• Three types of development and birth
• Monotremes, Marsupials, and Placentals
• Young depend on mother for food and protecting