Phylum Chordata

1
Phylum Chordata

• Deuterostome development
• Dorsal hollow nerve cord from ectoderm
• Notochord
• Stiff rod between nerve cord intestine
• Support for muscular movements
• Pharyngeal gill slits
• Slits allow water to escape before stomach
• Post-anal tail

2
Phylum Chordata

• Subphylum Urochordata
• Tunicates (sea squirts)
• Sessile adults filter water with gill slits
• Incurrent excurrent siphons
• Subphylum Cephalochordata
• Lancelets
• Mobile adults bury body in sand w/ mouth out
• Filter-feed across gill slits

3
Subphylum Vertebrata

• Cranium around brain
• Cartilaginous or bony vertebrae around nerve cord
• Except hagfishes
• Diversity of vertebrates
• Superclass Agnatha (hagfish lampreys)
• Jawless fish
• Lack paired appendages
• Cartilaginous skeleton
• Superclass Gnathostomata (jawed mouth)

4
Vertebrata

• Class Chondrichthyes (sharks, rays, skates)
• Cartilaginous fishes
• Some are oviparous (release eggs)
• Some ovoviviparous (release after hatching)
• Some are viviparous (nourished by placenta)

5
Vertebrata

• Class Osteichthyes
• Bony fishes (ossified skeleton)
• Ray-finned, Lobe-finned, lung fishes
• Ray-finned has most species
• Gills covered by operculum
• Swim bladder regulates buoyancy

6
Terrestrial vertebrates

• Class Amphibia
• Amniotes
• Class Reptilia
• Class Aves
• Class Mammalia

7
Class Amphibia

• Tetrapod vertebrates
• Ectothermic
• Developing eggs larva need aquatic environment
• Gas exchange through skin, gills, lungs, /or
  mouth
• Orders
• Order Anura (frogs toads)
• Order Urodela (salamanders)
• Also caecilians

8
Amniotes

• Amniotic egg contains extra-embryonic membranes
• Amnion surrounds embryo
• Allantois for waste disposal
• Yolk sac stored nutrients for embryonic growth
• Chorion surrounds all these (exchanges gases)
• Allow reproduction away from water

9
Class Reptilia

• Internal fertilization
• Leathery shelled amniotic eggs
• Some have live birth (ovovivipary vivipary)
• No larval stage of development
• Dry, scaly skin
• Lung respiration
• Nitrogenous waste is uric acid
• Ectothermic

10
Class Reptilia

• Order Testudines
• Sea turtles, tortoises, terrapins
• Order Squamata
• Lizards Snakes
• Order Crocodilia
• Crocodiles, caimans, alligators

11
Class Aves

• Hard-shelled egg
• Adapted for flight
• Hollow bones
• Endothermic
• Air sacs in addition to lungs
• No teeth (gizzard does grinding)
• Feathers
• Bipedal (forelimbs are wings)

12
Class Aves

• 29 (or so) living orders with gt8,500 species
• Order Anseriformes (Ducks, geese, swans)
• Order Piciformes (Woodpeckers)
• Order Falconiformes (Hawks, flacons, eagles)
• Order Galliformes (Chickens, turkeys, etc.)
• Order Passeriformes (songbirds)
• Sparrows, finches, cardinals, mockingbirds, jays,
  crows, wrens, thrushes, etc

13
Class Mammalia

• Endothermic
• Hair
• Mammary glands
• Some oviparous (egg-laying)
• Monotremes (platypus echidna)
• Most viviparous (nourished by placenta)
• Marsupials
• Eutherians

14
Class Mammalia

• About 4,500 species in 20 orders
• Order Monotremata (platypus echidnas)
• Order Marsupialia (opossums, kangaroo, koala,
  etc)
• Order Chiroptera (bats)
• Order Carnivora (lions tigers bears!, also
  weasels, dogs, raccoons, seals, etc)
• Order Cetacea (whales, dolphins)
• Order Rodentia (rats, squirrels, beaver, etc.)
• Order Primates (lemurs, monkeys, apes, you)

15
Order Primates

• Prosimians (e.g. lemurs)
• Old-world monkeys (non-prehensile tails)
• New-world monkeys (prehensile tails)
• Apes
• Gibbons
• Orangutans
• Chimpanzees
• Gorillas
• Humans

16
Homonid evolution

• Bipedalism
• Brain size
• Reduction in sexual dimorphism
• Perhaps with switch to monogamy
• Extended parental care
• Tool use
• Split from other ape ancestor some 5-7 million
  y.a.
• Diversified into Australopithecus and Homo