LS_L04_Animal Body Plans_III_2011

LS_L04_Animal Body Plans_III_2011 - Chordates • ...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chordates •  Notochord •  Pharyngeal gill slits •  Dorsal hollow nerve cord LIVING SYSTEMS Dr Elizabeth May Animal bodyplans III Dr E. L. May 1 A note about nervous systems Animal bodyplans III Dr E. L. May 2 Nervous systems •  Many invertebrates have a ventral nerve cord •  Chordates (hence all vertebrates) have a dorsal, hollow nerve cord •  Cnidarians have a nerve net with no central organising region •  Platyhelminthes (and all bilateral animals) have a concentration of nerve tissue at the head end (cephalisation) Animal bodyplans III Dr E. L. May 3 Animal bodyplans III Dr E. L. May 4 Invertebrate chordates •  •  •  •  Invertebrate chordates Sea squirts (urochordates) Filter feeders Larva has notochord in tail only Larva settles, metamorphoses into adult (loses •  Amphioxus (a cephalochordate) •  Notochord extends into head •  Supports body as animal burrows notochord and nerve cord!) Animal bodyplans III Dr E. L. May 5 Vertebrates Vertebrates •  Cranium •  Vertebral column JAWS 4 LEGS TERRESTRIAL EGG •  Fishes •  Amphibians •  Reptiles •  Birds •  Mammals (replaces notochord in most adults) •  Bony [Ca3(PO4)2] and/ or cartilaginous endoskeleton •  Notochord lost in adult (most) Animal bodyplans III Dr E. L. May 6 Animal bodyplans III Dr E. L. May 7 Animal bodyplans III Dr E. L. May 8 Fishes Jawless fishes: Agnatha •  Jawless fishes: lampreys and hagfishes •  Jawed fishes •  Lampreys and hagfishes •  Feed with rasping teeth around circular mouth •  Cartilaginous endoskeleton •  Notochord persists in adults •  Chondrichthyes (cartilaginous fishes) (sharks and kin) •  Osteichthyes (bony fishes) •  Ray-finned fishes •  Fleshy-finned fishes (e.g. lungfishes) 9 Animal bodyplans III Dr E. L. May Mouth of lamprey Hagfish Hagfish slime Animal bodyplans III Dr E. L. May Chondrichthyes 10 Osteichthyes •  Cartilaginous jawed fishes •  Denticles in skin (sailor’s sandpaper) •  Bony fishes •  Scales •  Highly successful: very flexible jaw articulation; swim bladder for buoyancy Seven-gilled shark •  Fleshy-finned: lungfishes, coelacanth •  Ray-finned: salmon, tuna, guppy, trout, goby, herring, eel, etc., etc., etc. Ray Animal bodyplans III Dr E. L. May 11 Animal bodyplans III Dr E. L. May 12 Remarkable diversity of bony fishes But did you know …? •  8 mm - over 12m •  ~ 25, 000 species (greatest diversity in •  Many can change sex •  Deep sea fishes can produce light •  Some produce electric shock •  Some survive in freezing waters (contain tropics) •  ~ 85 jawless; ~ 950 cartilaginous; ~ 24, 000 bony fishes antifreeze in blood) •  Freshwater, marine, diadromous (migrate between FW and marine) 13 Animal bodyplans III Dr E. L. May http://www.hollywoodjesus.com/ finding_nemo_photo.htm Animal bodyplans III Dr E. L. May Gills vs lungs Amphibians •  Requirements of a gas exchange surface: thin, moist, large SA, well-vascularised •  Gills: evaginations of body surface (external, aquatic •  Evolved from fleshy-finned fishes •  Permeable skin •  Metamorphosis from aquatic larva (tadpole gills) to terrestrial adult (lungs) •  External fertilisation •  Lay eggs in water •  Tetrapods: four legs Animal bodyplans III Dr E. L. May 14 and marine organisms) 15 Animal bodyplans III Dr E. L. May 16 Gills vs lungs Review: Insect Trachea •  Lungs: invaginations of body surface (internal to resist dessication; terrestrial organisms) Limit to body size 17 Animal bodyplans III Dr E. L. May Reptiles Amniote egg (eggs on land) •  Extra-embryonic membranes •  Scales •  Lungs •  Amniote egg •  Internal fertilisation •  Modifications of skeleton for support on land •  Lizards, snakes, turtles, tuatara, dinosaurs Animal bodyplans III Dr E. L. May 18 Animal bodyplans III Dr E. L. May 1. Amnion: fluid-filled to protect embryo 2. Yolk sac: food supply 3. Gas exchange and waste storage 19 Animal bodyplans III Dr E. L. May 20 Birds Mammals •  Feathers •  Flight •  Hollow bones •  Endothermy •  4-chambered heart •  Descendants of dinosaurs • Fur • Milk (mammary glands) • Lots of glands (smelly!) • Endothermy • Three inner ear bones • 4-chambered heart 21 Animal bodyplans III Dr E. L. May Monotremes •  •  •  •  Marsupials Egg-laying mammals Platypus, echidnas Electroreception No teats Animal bodyplans III Dr E. L. May 22 Animal bodyplans III Dr E. L. May •  Pouch in females •  Short gestation and altricial neonates •  Name twelve! 23 Animal bodyplans III Dr E. L. May 24 Eutherians Amniote phylogeny •  Long gestation and well-developed (precocial) neonates •  Foetus feeds via placenta Reptiles (but also present for short time in marsupials) •  Name twelve! Birds Mammals 25 Animal bodyplans III Dr E. L. May Animal bodyplans III Dr E. L. May 26 Take Home messages / body plan summary •  Diploblastic / triploblastic •  Symmetry •  Bilateral animals acoelomate / pseudocoelomate / coelomate protostome / deuterostome Characters and examples of major taxa Adaptations for terrestrial life? (gas exchange, body covering, water loss, e.g. amniote egg!) •  Chordates •  •  •  •  Ecdysozoa acoelomate coelomate •  Distinguishing characters of fish, amphibians, reptiles, birds and mammals •  Recognise Australian fauna - marsupials and monotremes! pseudocoelomate Figure 38.2 Animal bodyplans III Dr E. L. May 27 Animal bodyplans III Dr E. L. May 28 ...
View Full Document

This note was uploaded on 10/17/2011 for the course PSYC 2012 taught by Professor ? during the Three '11 term at University of Sydney.

Ask a homework question - tutors are online