Organismal Biology — Lab 12 online
PHYLUM CHORDATA

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Class AGNATHA (Jawless fishes)

Lamprey, a modern cyclostome


ORIGIN OF JAWS

Jaws probably evoloved from gill arch supports.



Dunkleosteus, also known as Dinichthys, was a large fish up to 15 meters (50 feet) long.
Vertebrates were not an ecologically important group of animals until jaws evolved.



Class CHONDRICHTHYES



Notice the heterocercal tail in this shark,
and the 5 externally visible gill slits




Class OSTEICHTHYES

Anatomy of a bony fish.
Notice the swim bladder, a lung that has been transformed
into a hydrostatic organ capable of controlling buoyancy (and thus the depth at which the fish swims)







Latimeria, the only living member of the Crossopterygii




Class AMPHIBIA










Class REPTILIA

A box turtle

   
Crocodiles



Family tree of dinosaurs.
Notice, in the lower corners, the different pelvic girdle structure in the two orders.



A lizard. Notice the sprawling posture typical of reptiles.



Closeup of a lizard, showing the scaly skin.


   
Snakes


Closeup of snake skin




Birds (AVES)
   
Cassowary (a flightless bird)                                     Frigate bird             .

   
Woodpecker (notice the sharp, chisel-pointed bill)                                 Pigeons                                            

   
Two perching birds (order Passeriformes)
The toes of these birds grip tightly around small branches,
even while the bird is asleep. It takes muscular effort to
release the grip, but not to maintain it.



MAMMALS (Class Mammalia)

An early member of the order Carnivora Ruminant artiodactyls have a partitioned stomach, with four chambers

Order Marsupialia: opossums, kangaroos, koalas, etc.

Order Lipotyphla (Insectivora): moles, shrews, etc.
Order Chiroptera: bats
Order Rodentia:   rats, mice,   squirrels, beavers, porcupines, etc.
Order Lagomorpha:   rabbits	Order Pholidota:   pangolins	Order Tubulidentata:   aardvarks
Order Carnivora: dogs, bears, racoons, weasels, skunks, cats, hyaenas, civets, seals, walruses
Order Cetacea: whales, porpoises, dolphins
Order Perissodactyla: horses, rhinos, tapirs		Order Proboscidea: elephants
Order Artiodactyla: pigs, hippos, camels, deer, giraffes, antelopes, goats, sheep, cattle