Anatomic Diversity Human anatomy is a typical anatomy of a member of Phylum Chordata. Human anatomy understood biologically within its comparative and developmental.
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Anatomic Diversity Human anatomy is a typical anatomy of a member of Phylum Chordata. Human anatomy understood biologically within its comparative and developmental contexts. Understanding the development of vertebrate (in this case human) anatomy is necessary to understand the adult anatomy across vertebrates. Phylum Chordata Notochord = stiff connective tissue rod Dorsal hollow nerve cord (neural tube) = hollow nerve cord dorsal to notochord (spinal cord + brain in us) Endostyle/thyroid = gland involved in iodine metabolism Pharyngeal Openings (gill openings) = openings into “throat,” behind mouth Post-anal tail Phylum Chordata Phylum Chordata Subphylum Urochordata Subphylum Cephalochordata Subphylum Myxini Subphylum Vertebrata notochord, neural tube, post-anal tail, endostyle/thyroid, pharyngeal openings Subphylum Urochordata Sea Squirts, Salps, & Larvaceans Suspension feeders Tadpole larva with notochord in tail. Sea Squirt Metamorphosis Subphylum Cephalochordata Lancelets (Amphioxus, Branchiostoma) Suspension feeders Notochord extends into head & includes skeletal muscle cells. Chordate derived characteristics obvious. Chordate Synapomorphies dorsal nerve tube notochord intestine anus pharyngeal basket (slits) hepatic diverticulum post-anal tail Phylum Chordata notochord extends into head tadpole larva segmental muscles notochord, neural tube, post-anal tail, endostyle/thyroid, pharyngeal openings Lancelet Musculature Musculature Lancelets, hagfishes, & vertebrates have segmental muscles (myotomal muscles). segmental muscles (myotomal muscles) Lancelet Tail Section nerve tube myotomal muscles notochord Lancelet Structure Sketch on board. Craniata Hagfishes and vertebrates. SYNAPOMORPHIES Cranium (cartilage or bone) Liver Calcium phosphate in skeleton Neural crest tissue (Developmental) Neurogenic placodes (Developmental) Phylum Chordata notochord extends into head segmental muscles notochord, neural tube, post-anal tail, endostyle/thyroid, pharyngeal openings Craniate Phylogeny liver, CaPO4, neural crest, neuro. placodes Hagfishes, Subphylum Myxini 43 species; marine scavengers no jaws lack functional eyes, tentacles, & one naris serially hermaphroditic lack bone (cartilage) secrete slime Hagfish Anatomy Cartilage under brain and in mouth apparatus. Keratinous tooth plates. No real vertebrae. Hagfishes, Subphylum Myxini tentacles mouth pharyngeal openings caudal fin Hagfishes, Class Myxini Hagfish Slime Subphylum Vertebrata Approximately 50,000 species. Vertebrates arose in the marine enviro. SYNAPOMORPHIES Dorsal Fin with skeletal supports Vertebrae – complete neural arches Vertebrae Craniate Phylogeny dorsal fin, complete neural arches Lampreys Class Petromyzontida 41 species Oral disc with “teeth” & rasping “tongue” Ammocoete larva - VERY similar to cephalochordates in way of life Larvae undergo metamorphosis. Marine and freshwater ectoparasites (adults) and suspension feeders (larvae) Lampreys, Class Petromyzontida oral disc 1 narial opening eye pharyngeal openings keratinous “teeth” dorsal fins Lampreys, Class Petromyzontida ammocoete larva adult Lamprey, ammocoete neural tube brain – spinal cord notochord intestine anus pharyngeal basket (slits & bars) endostyle liver heart Sketch on board. post-anal tail Lab Activity Obtain a slide of a lamprey ammocoete and a dissection microscope. Examine the slide on the microscope. If appropriate, date the page in your lab notebook and sketch the ammocoete. Label all the parts you labeled on the previous slide. Ask your instructor if you have difficulty. Examine the whole preserved lampreys. Lab Activity Obtain a slide of a cross sectioned ammocoete larva and a compound microscope. Find the section through the post-anal tail and examine the slide on the microscope. Sketch the tail section. Label the notochord, myotomal muscles, & neural tube. Ask your instructor if you have difficulty. Gnathostomata gnatho- = jaws; stoma = mouth jawed vertebrates pectoral & pelvic fins Myelinated nerves Craniate Phylogeny jaws, myelin, paired limbs Sharks, Rays, Chimaeras, etc. chondro- = cartilage; ichthys = fish Sharks, rays, sawfishes, & chimaeras Males have pelvic claspers. marine (and freshwater) carnivores Approx. 850 species Class Chondrichthys Osteichthys osteo- = bone; ichthys = fish “bony” vertebrates, NOT just FISHES bony endoskeleton, lung(s) ray-finned fishes, lungfishes, the coelacanth, & terrestrial vertebrates Craniate Phylogeny bony endoskeleton, lung(s) Class Actinopterygii actino- = ray; ptery = fin or wing ray-finned fishes marine and freshwater 24,500+ species (= the number of species of all other vertebrates put together) Very diverse in habits and body form. Class Actinopterygii single, dorsal lung 24,000 species+ Sarcopterygii sarco- = flesh; ptery = fin or wing fleshy & bony pectoral and pelvic axis lobe “fins” (NOT just FISHES) lungfishes, coelacanths, & terrestrial vertebrates Craniate Phylogeny “lobes” Coelacanths 2 species deepwater marine (East Africa & Indonesia) Lungfishes 6-9 species, Tropical freshwaters unique morphology Paired ventral lungs Tetrapoda tetra- = four; poda = foot “terrestrial” vertebrates pectoral and pelvic limbs with digits 1 3 2 4 1 2 Craniate Phylogeny limbs with digits Amphibians amphi = both/double, bios = life frogs, toads, salamanders, caecilians Usually distinct metamorphosis Approx. 5,000 species freshwater and terrestrial (none marine) mucus covering skin Amphibians Amniota Amnion = amniotic membrane Amniotic membrane surrounds embryo (in egg or in uterus) amniotes = reptiles & mammals Very distinct from other vertebrates Craniate Phylogeny amnion Class Mammalia Mammals Named for mammary glands Hair (no exceptions) Approx. 4000 species Most diverse = rodents and bats. Theria nipples hair, mammary glands Monotremes Platypus & Echidnas Australia & New Guinea. Lay eggs Young lap up milk from nipple-less mammary glands Baby Platypus Echidnas Marsupials Metatherians Australia, New Guinea, & S. America Morphologically diverse in Australia Do not lay eggs, young develop in an external pouch. Milk from nipples Eutherians “Placental” mammals Worldwide, Very diverse morphologically Do not lay eggs; young do not develop in an external pouch. Milk from nipples. Class Reptilia Turtles, lizards, snakes, tuataras, crocodylians, & birds Birds ARE reptiles Thick keratin scales Approx. 15,000 species Many extinct epidermal scales of beta keratin Turtles Turtles, tortoises, & terrapins Worldwide, <1000 species Ribs and vertebrae form a “shell” (test). No teeth, keratinous “beak” Lay eggs. Lepidosaurs: Lizards & Snakes Lizards, snakes, & tuataras Worldwide 5000+ species Subclass Archosauria Crocodilians Alligators, crocodiles, caimans, and gavials about approx. 40 species Subclass Archosauria Birds Aves 9,000 species Feathers, no teeth, keratin beak