Chordates

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Chordates

• NonVertebrate Chordates, Fish, Amphibians,
  Reptiles and Mammals

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General Chordate Characteristics

• At some stage of development, all vertebrates
  share the four features
• 1. Notochord-long supportive rod that runs
  through the body, most only have it while embryos
• 2. Dorsal hollow nerve cord-nerves branch from
  this cord and connects to internal organs,
  muscles and sense organs
• 3. Pharyngeal gill slits-paired structures in the
  throat region, in some develop gills
• 4. Tails-can contain bone and muscle, used for
  swimming in some adult species.

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Endoskeleton

• Internal skeleton
• Made of either bone or cartilage
• Grows with the body, allows vertebrates to grow
  to large sizes
• Most have a strong supporting structure known as
  the vertebral column, or backbone
• The vertebrae enclose and protect the spinal
  cord.

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Control of Body Temperature

• Endotherms- use metabolic heat to keep tissues
  warm
• Live in a wider range of climates than
  ectotherms.
• Ectotherms-regulate body temperature by
  surrounding envrionment.

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Development

• Bilateral symmetry
• Deuterostome
• Coelomate

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Nonvertebrate Chordates

• Tunicates-closest relatives to vertebrates
• Filter feeders, mobile larvae, sessile adults
• Lancelets- small fishlike creature that is mobile
  from larval to adult form
• -keep all four structures from birth through
  adulthood

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Jawless Fish, Agnatha

• Body temp regulation Ectothermic (all fish exist
  in homeostasis at the same temperature as their
  surroundings)
• Skin/body skin covering the body, no scales, no
  fins or limbs, no jaws, eel-like body with
  compressed caudal fin.
• Skeleton cartilaginous endoskeleton
• Feeding carnivores, parasites and scavengers
• Respiration gills
• Circulation open circulatory system

Gills are shown above
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• Excretion ammonia waste released through the
  gills into the surrounding water
• Solid waste is excreted through cloaca (a orifice
  that combines the urinary, digestive, and
  reproductive tracts)
• Reproduction hermaphroditic, external
  fertilization
• Sense organs lateral line that is used to detect
  movements and vibrations in surroundings
• Examples hagfish and lampreys

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Cartilaginous Fish, Chondroicthyes

• Body temp. regulation Ectothermic
• Skin/body Denticles (tooth-like scales covering
  the skin), paired fins, mouth with several rows
  of triangular teeth, large caudal fin
• Skeleton cartilaginous endoskeleton.
• Feeding carnivores (predators) and filter
  feeders.
• respiration gills
• Circulation Closed system, 2-chambered heart
  pumps blood around the body in a single loop
  system.

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• Excretion kidneys filter wastes from blood and
  conserve water loss during excretion
• Solid waste is expelled through cloaca.
• Reproductionare Viviparous (embryos stay in the
  mothers body after internal fertilization and
  young are born alive)
• Sense organs lateral line
• Examples- Sharks and rays

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Bony Fish, Osteoicthyes

• Body temp regulation Ectothermic
• Body/Skin broad flat scales and skin that
  secretes mucous to reduce friction while fish
  swim, paired fins made of rays/spines (ray fins)
  and fins with out rays/spines (lobed fin)
• Skeleton bone.
• Feeding as predators, scavengers, detrivores,
  and filter feeders.
• Respiration gills (have an operculum to regulate
  water over gills)

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• Circulation 2 chambered heart, (1 way
  circulation) countercurrent flow of the movement
  of water against the flow of blood in the fishs
  gills.
• Excretion kidneys filter wastes and prevent
  water loss during excretion
• Solid waste is expelled through cloaca.
• Reproduction species determine
  internal/external fertilization, most are
  oviparous (external fertilization) (eggs hatch
  outside the mothers body) some are
  ovoviviparous(eggs stay in mothers body after
  internal fertilization, develop inside egg and
  are born alive)
• Sense organs lateral line system

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• Presence of swim bladder to help maintain
  buoyancy
• Transitional species lobed fin fish thought to
  be the precursor to amphibians.
• Examples Guppies, Salmon, angelfish, goldfish,
  perch

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Amphibians

• Body temp regulation Ecothermic
• Skin/body They have smooth moist skin. Internal
  skeleton is made of bone. (large shoulders and
  hip bones allowed movement from water to land)
• Tympanic membrane-detect sound vibrations (copy
  down on your sheet!)
• Feeding Carnivores and insectivores
• Respiration larva diffusion through skin and
  gills, adults poorly developed lungs also rely
  on skin

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Amphibians

• Circulation 3 chambered heart that is composed
  of 2 atria and 1 ventricle, double loop system
• Excretion Kidneys filter liquid waste and it is
  released from the bladder, solid waste is removed
  through the cloaca .
• Reproduction is mainly external, with the
  exception of caecilians which is internal
• Must release eggs (through cloaca) in a moist
  environment (some lay directly in water, other
  moist ground, or in sacs on the females back

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• Amphibians start life cycle under water and move
  to land at adult hood. (Double life)
• May go through metamorphosis
• Examples toads, frogs, salamanders and caecilians

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Reptiles

• Body temp regulation Ecothermic
• Skin/body Dry scales, toes with claws, body plan
  better adapted to living on land
• Skeleton bone
• Feeding Carnivores and herbivores.
• Respiration Lungs are spongy, allows for more
  gas exchange. Most reptiles have 2, snakes only
  have 1 lung.

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• Circulatory Have a double loop. Non Crocodilian
  have a 3 chambered heart. Crocodilian reptiles
  have a 4 chambered heart.
• Excretion Kidneys, bladder and cloaca are used
  to eliminate waste.
• Reproduction Fertilization is internal and first
  animals to use an amniotic egg for offspring, may
  have oviparous birth (eggs deposited into an
  external nest) or viviparous (reptile retains egg
  and gives birth to live offspring)

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Amniotic Egg

• Amniotic eggs have a tough shell that is almost
  completely waterproof, and contains all the
  developing embryo needs until it is ready to
  break free from shell.

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Reptiles

• Examples include Snakes, lizards, turtles,
  alligators, and crocodiles

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Aves

• Body Temp Regulation Endothermic
• Body/Skin Feathers and dry scales cover the
  body, horned beak, no teeth, rearranged muscle in
  hips and legs, forelimbs are wings
• Skeleton hollow bone, fused collarbones that
  form v-shape wishbone
• Feeding Carnivores, Insectivores, Herbivores,
  Nectivores
• Respiration Lungs with air sacs, allows for more
  efficient oxygen exchange with unidirectional
  flow.

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Aves

• Circulation Have a 4 chambered heart composed of
  2 atria and 2 ventricles.
• Excretion Kidneys and cloaca are used to
  eliminate waste. Birds do not urinate (with the
  exception of the ostrich).
• Reproduction Fertilization is internal and use
  an amniotic egg with a hard shell for offspring,
  Have oviparous birth (eggs deposited into an
  external nest).

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Aves

• Examples include extinct archeopteryx,
  hummingbird, green woodpecker, blue-footed booby,
  bald eagle

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Mammals

• Body temp regulation Endothermic
• Skin/body Hair covers the body, have middle ear
  bones to detect sound
• Skeleton made of bone
• Feeding Carnivores, Omnivores, and Herbivores
• Respiration Lungs are spongy, allows for more
  gas exchange. All mammals have 2

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Mammals

• Circulatory system Have a 4 chambered heart
  composed of 2 atria and 2 ventricles.
• Excretion Kidneys, bladder, anus and sweat
  glands (not all mammals) are used to eliminate
  waste.
• Reproduction Fertilization is internal.
  However, mammals are classified differently
  depending on how they give birth.
• Most have sweat (used also to eliminate heat)
  and sebaceous (fat secreting) glands
• Produce milk to nourish young, using mammary
  glands

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Placental Mammals

• All bear live young, which are nourished by
  placenta (a specialized embryonic organ attached
  to the uterus wall) before birth in the mother's
  uterus

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Placental Mammals

• Examples include
• Humans
• Dolphins
• Field mice
• Badgers

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Marsupial Mammals

• No placenta.
• After 4-5 wks., young emerge from the birth canal
  in an extremely undeveloped state.
• Immediately after birth, the tiny offspring,
  crawls along its mothers body and finishes
  developing attached to a nipple located inside
  the mothers pouch.

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Marsupial Mammals

• Examples include
• Koalas
• Kangaroos
• Sugar gliders
• Opossums

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Monotreme Mammals

• Mammals with reptilian-like features including a
  cloaca.
• These mammals lay reptile-like eggs.
• After the babies hatch, the mothers nourish their
  young with milk.

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Monotreme Mammals

• Examples include
• Duck-billed platypus
• Echidna