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Home , Chordate, Gill, Hagfish, Tunicate

The Diversity of 2 Phylogeny of Animalia (overview)

Chapter 23

Key features of embryo: features • Chordata (the Chordates) includes both and that share (at some point in their :  Dorsal, hollow cord Pharyngeal slits Post-anal

Invertebrate chordates

• Have a notochord, but not a true • Example: tunicates Have all 4 chordate features as larvae Lose Post-anal tail Notochord Most of dorsal hollow nerve tube Keep Pharyngeal gill slits larvae  expands, used for filter-feeding

1 Vertebrates 1: Jawless Vertebrates Vertebrates 1: Jawless vertebrates • Example 2: Lampreys • Example 1: These do have a vertebral column, and thus are true Don’t have a true vertebral column vertebrates Not really vertebrates, but usually grouped with them. Parasites on other Use -like mouth with rasping teeth (inside mouth and on Secrete copious amounts of enzymatic slime to tongue) to latch on and suck and body fluids digest prey!

Vertebrates 2: Cartilaginous Rays & • New (derived) features   Paired appendages  Mineralized  But reduced in the cartilagenous fish… (do have mineralization in teeth, parts of skeleton)  Thought to have evolved from more mineralized fishes • Many cartilaginous fish are predators • Examples: Rays and sharks

Vertebrates 3: Bony fishes Vertebrates 3: Bony fishes

• New (derived) feature: • Bony fish diversity Gives rise to in land vertebrates! NOTE: Mineralized bone is not a new feature despite the fact that they are the bony fishes!

Seahorse : Long snout for feeding on Deep sea : reduced , long and mobile tail for mineralization; reduced and hanging onto coral and algae, male attached males has pouch for brooding young

2 Vertebrates 4: and • Amphibians live “double ” Aquatic as larvae Gain with Move with tail Semi-terrestrial as adults Gain oxygen with lungs and through skin Move with legs Still tied to for ; will dry out without water; many with external fertilization

Vertebrates 5: Vertebrates 5: Reptiles • Reptiles, and many are adapted for terrestrial life • Other adaptations of reptiles and birds to Key feature: amniotic terrestrial life Has shell that allows without water loss (Nature’s Gortex!) Tough, scaly skin resists water loss Internal membrane (amniotic sac) is fluid-filled and houses embryo Internal fertilization Reproduction is thus no longer tied to water More efficient lungs and Better adapted than amphibians for air-breathing Birds have extremely efficient lungs!

Vertebrates 5: Reptiles (diversity) Vertebrates 6: Birds

• Birds are closely related to reptiles (“feathered reptiles”)  (and similar “-birds”) show relationships between reptiles and birds and • Only found on New • Largest reptiles Zealand • Closely related to

Snakes

3 Vertebrates 6: Birds Vertebrates 6: Birds (Diversity) • Birds are adapted for flight Feathered wings (airfoils) Light for flight! Hollow spaces in bones Reduction of organs (i.e. single ) Absence of teeth Endothermic Higher metabolic rates needed for flight • Largest (up to • Tiny (juvenile) 300 pounds) Acute visual systems •60 cycles/sec wingbeat • Type of seabird • Many seabirds are • Flightless Coordination of flight extraordinary long- Efficient and circulation distance travelers and fishers

Vertebrates 7: Mammals (Groups) Vertebrates 7: Mammals • (Example: -billed )  Egg-laying mammals • Key features  Have mammary gland but no nipples; young lick milk off fur. • ( and ; primarily in Australia)  Hair  Born early in development; completes development while nursing (usually in pouch) Provide milk to their • Placental mammals offspring  Complete within uterus  Extensive placenta where exchange of nutrients and gas Via mammary glands between mother and offspring

Monotremes Marsupials

4 Placentals

5