Animal Diversity II: Vertebrates
BIO 101
Life Science
Dr. D. L. Daley
Phylum Chordata
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Four
features that all chordates have at some time in their life cycles
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Notochord - long stiff rod - helps support the body
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Dorsal, hollow nerve cord
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Pharynx with gill slits (used in filter feeding)
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Pharynx functions in respiration as well as feeding in many chordates
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Post-anal tail
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Important in locomotion in many chordates
Chordate
Classification
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Urochordata - tunicates
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Cephalachordata - lancelets
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Vetebrata - animal with a backbone
Urochordata - Tunicates
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Surrounded by a leathery “bag” called a tunic
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Tadpole larva with notochord extending to tail
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Undergo metamorphosis into adult form
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Sea squirts & relatives
Sea Squirts
Cephalochordata - Lancelets
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Typically burrow into the bottom
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Fishlike body
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Filter feeders
Vertebrates
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Agnatha - jawless fish
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Chrondrithyes - cartilaginous fish
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Osteichthyes - bony fish
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Amphibia - frogs, salamanders & others
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Reptilia - snakes, lizards & turtles
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Aves - birds
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Mammalia - mammals (bats, whales, primates, horses, cows,
rabbits, dogs and cats)
Agnatha
w Jawless vertebrates
w Hagfish - prey on marine worms
& scavenge for weakened or dead organisms
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Produce lots of slime as a defense
w Lamprey - most are parasites
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Attach to side of a fish with oral disk with horny teeth - feed on the
insides of the fish
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Larval form matures in freshwater & then migrates to the sea
Hagfish and
Lamprey
Chrondrithyes - Cartilaginous Fish
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Sharks, rays, skates and ratfish or chimaera
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Cartilage skeletons & no swim bladder or lung
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Spiral valve in intestine
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Scales - small bony plates - backward pointing hooks
Sharks and Rays
Osteichthyes - Bony Fish
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Swim bladders - adjustable flotation device
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Lobed finned fish
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Lungfishes
- one or two lungs - freshwater
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Coelacanths
- have lungs - marine
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Ray finned fish
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Most
diverse group
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Paddlefish
& Sturgeons
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Gars & Bowfins
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Trout,
perch, eels, tuna & sea horses
Bony Fish
Amphibians
w Salamanders - live in
temperate & tropical regions
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Spawn in water - larval form matures in the water
• All carnivorous
Amphibians
w Frogs and Toads
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Mucous glands - keeps skin moist - slip away from predators
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Poison glands - many are neurotoxins
• Have sticky-tipped tongue
for prey capture
Amphibians
Amphibians
w Caecilians
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Wormlike amphibians - no legs
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Live by burrowing through moist soil
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Eat insect and earthworms
• Most are Blind
Reptiles
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Tough dry scaly skin - restricts water loss
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Fertilization of eggs is internal
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Have amniote eggs - eggs that have
membranes to retain water,
protect and metabolically support the developing embryo
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Now
embryo can hatch on land
Turtles
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Body enclosed in two part shells of dermal plates fused to vertebrae
& ribs
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Jaws without teeth
Lizards, Worm
Lizards & Snakes
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Body covered with dermal scales - skin shed periodically
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Jaws with teeth
More Snakes
Crocodilians
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Crocodiles, alligators and caimans
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First vertebrates -
4 chambered heart
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Separate
respiratory circuit & systematic circuit
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Stout body - two pairs of limbs - webbed clawed toes
Crocodilians
Aves - Birds
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Only organism to grow feathers
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Feathers
- lightweight - insulation and flight
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Scales on feet only
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Tetrapod with forelimbs modified as wings
Flightless Birds
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Ostriches, rheas, cassowaries, emus & kiwis
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Sternums shaped like flat-bottomed boats without keels for flight
muscle attachment
All Other Birds
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Deep sternal keels for attachment of flight
muscles
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Good fliers except some like penguins, have secondarily become
flightless
Mammals
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Hair (maintain body temp) & mammary glands
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Females
feed young with milk
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Care for young for extended periods
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Most mammals secure, cut and sometimes chew food before swallowing it
Monotremes
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Egg-laying mammals
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Adults lack teeth
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Duck-billed platypus & echinas (2
species)
Marsupials
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Pouch - marsupium on the mothers belly
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Most are unique to Australia - free from competition from placental
mammals
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Examples are kangaroos and opossums
Marsupials
Neonate Marsupial
& Joey in Pouch
Placental Mammals
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Placenta - spongy - blood filled filled tissue of
maternal and fetal origin
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Forms
in mothers uterus - delivers nutrients and oxygen & removes wastes
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Placental mammals grow faster & most are born fully formed
Assorted Mammals
Whales
Primates
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Prosimians - lemurs, tarsiers and lorisers
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Arboreal
- tree dwellers
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Simians - monkeys and apes
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Hominids
- Apes and humans