Lecture 19 07/09/2015
Lecture 19 07/09/2015 PDF Animal Diversity:From Molluscs to Chordates (Phylum) Mollusca
1.Classification(Class) 1)Polyplacophora 2)Bivalvia 3)Gastropoda 4)Cephalopoda 2.General character
1.mostly marine(some freshwater, damp terrestrial) 2.Bilaterally symmetrical 3.Triplobalstic 4.Coelomate 5.Protostomes 6.Not segmented( Except Neopilina ) 7.Up to 8 classes 3.Basic characteristic(special)
1.Mantle(dorsal body wall forms shell) 2.Mental Cavity: space between mantle and main body where gill(or Lungs) are found 3.Muscular foot: for moving, feeding ,manipulation 4.Head with specialized mouthparts(radula) 4.Classification Detail 1)(Class)Polyplacophora
1.Chitons(coat-of-mail shells)
2.only marine 3.Bilaterally symmetrical 4.shell consists of 8 large plates surrounded by a girdle of smaller spicules 5.mostly feed on algae or encrusting organism,but some are predators 6.Reproduce —sexually —some brood their young in their mantle 2)(Class)Bivalvia e.g. Clams,mussels,oysters 1.Marine & freshwater 2.two shells, no distinct head 3.lost radula 4. filter feed(sometimes through foot) 5.often live buried in sand 6.Gills function —not only gas exchange —but also food collection 7.Trocophore larvae typical 3)(Class)Gastropoda e.g. 1.snails 1.Torsion— develop body twists e.g. 2. Slugs 2.Detorsion— body twisting is lost 1)General features 1.Marine,freshwater,and terrestrial 2.spiral shell(lost in slugs) 3.Produce slime (aids movement) 4.well-developed head with eyes and tentacles 5.Larvae=bilaterally symmetrical 6.Adult snails= body twisted(torsion) 2)Torsion in snails 1)180 degree turn in body inside shell 2)Advantage —Mantle cavity anterior (allows withdrawal into shell) 3)Disadvantage:anus empties by mouth 3)Detorsion in Slugs 1.lost shell 2.Mantle is massively reduced 3.no mantle cavity 4.Detorsion(body twisting is lost) 5.may allow slugs to forage in soil or andy substrates(sea slugs)
4)(Class)Cephalopoda e.g. Squid,octopus,cuttlefish,Nautilus 1.General features 1)Marine,free-swimming 2)Shell reduced to internal support(except in Nautilus) 3)Mantle used for propulsion 4.Foot converted into tentacles
2.Exception —Nautilus 1.Shell—buoyancy aid 2.As Nautilus grows greater buoyancy is needed 3.Shell grows& Nautilus seals off gas-filled chambers ---------------------------------------------------------------------(Phylum)Echinodermata —(entirely making-5main classes) 1.Classification
1.Class Asteroidea e.g. Sea stars 2.Class Ophiuroidea e.g. Brittle stars 3. Class Echinoidea e.g. sea urchins 4.Class Crinoidea e.g. sea lilies 5. Class Holothuroidea e.g. Sea cucumbers 2.General characteristic 1)Radial symmetry(bilateral symmetry—larvae) 2)Triploblastic 3)Coelomate 4)Deuterostome 5)No segmentation 6)Spiny epidermis 7)Have a water vascular system in the coelom 3.Sea- Star body plan
1)ring canal—— radial canal 2)anus——Mouth on ventral side 3)Arm 4)Nerve ring 5)Tube feet 6)Madreporite 4.Echinoderm defence 1)Pedicellariae some asteroidea species) —modified spines with claws and capable of movement
—used to remove encrusting organisms 2)Ejection of intestines(some holothurians) —When startled some species will expel sticky tubules to entangle predators —May also discharge ad deadly toxin ----------------------------------------------------------------------(Phylum)Chordata 1.General charateristic 1.Maring, freshwater, terrestrial, aerial, subterranean 2.Bilaterally symmetrical 3.Triploblastic 4.Coelomate 5.Deuterostome 6.Partial segmentation 7.Reproduction —largely sexual and internal 2.Classification 1)subphylum: vertebrata e.g. amphibians,reptiles,fish,birds,mammals 2)Other subphylum 1)Urochordata—e.g. marine sea-squirts 2)Hemichordata—Marine’acorn-worms' 3)Cephalochordate—fish like lancelets 3.Notochord(defining feature of the chordates)
1)Notochord=stiff rod of mesoderm found next to the nerve chord in all chordate embryos(and some adults) 2)Functions as a endoskeleton(like a backbone) 3)Nerve chord located dorssally 4.Vertebrate —surround and protect the nerve chord
5.Cephalochordate —lack of jaws 1)lake jaws 2)earliest vertebrates shared this feature 3)later vertebrates developed jaws by modifying gill arches 6.Agnatha(jawless fishes, vertebrates) 1)496-360 million years ago—very diverse group of animals 2)early forms exoskeleton of bone in the skin(may even have had electroreception) 3)Now,only two small groups exist(lampreys and hagfish)
1.Classification(Class) 1)Polyplacophora 2)Bivalvia 3)Gastropoda 4)Cephalopoda 2.General character
1.mostly marine(some freshwater, damp terrestrial) 2.Bilaterally symmetrical 3.Triplobalstic 4.Coelomate 5.Protostomes 6.Not segmented( Except Neopilina ) 7.Up to 8 classes 3.Basic characteristic(special)
1.Mantle(dorsal body wall forms shell) 2.Mental Cavity: space between mantle and main body where gill(or Lungs) are found 3.Muscular foot: for moving, feeding ,manipulation 4.Head with specialized mouthparts(radula) 4.Classification Detail 1)(Class)Polyplacophora
1.Chitons(coat-of-mail shells)
2.only marine 3.Bilaterally symmetrical 4.shell consists of 8 large plates surrounded by a girdle of smaller spicules 5.mostly feed on algae or encrusting organism,but some are predators 6.Reproduce —sexually —some brood their young in their mantle 2)(Class)Bivalvia e.g. Clams,mussels,oysters 1.Marine & freshwater 2.two shells, no distinct head 3.lost radula 4. filter feed(sometimes through foot) 5.often live buried in sand 6.Gills function —not only gas exchange —but also food collection 7.Trocophore larvae typical 3)(Class)Gastropoda e.g. 1.snails 1.Torsion— develop body twists e.g. 2. Slugs 2.Detorsion— body twisting is lost 1)General features 1.Marine,freshwater,and terrestrial 2.spiral shell(lost in slugs) 3.Produce slime (aids movement) 4.well-developed head with eyes and tentacles 5.Larvae=bilaterally symmetrical 6.Adult snails= body twisted(torsion) 2)Torsion in snails 1)180 degree turn in body inside shell 2)Advantage —Mantle cavity anterior (allows withdrawal into shell) 3)Disadvantage:anus empties by mouth 3)Detorsion in Slugs 1.lost shell 2.Mantle is massively reduced 3.no mantle cavity 4.Detorsion(body twisting is lost) 5.may allow slugs to forage in soil or andy substrates(sea slugs)
4)(Class)Cephalopoda e.g. Squid,octopus,cuttlefish,Nautilus 1.General features 1)Marine,free-swimming 2)Shell reduced to internal support(except in Nautilus) 3)Mantle used for propulsion 4.Foot converted into tentacles
2.Exception —Nautilus 1.Shell—buoyancy aid 2.As Nautilus grows greater buoyancy is needed 3.Shell grows& Nautilus seals off gas-filled chambers ---------------------------------------------------------------------(Phylum)Echinodermata —(entirely making-5main classes) 1.Classification
1.Class Asteroidea e.g. Sea stars 2.Class Ophiuroidea e.g. Brittle stars 3. Class Echinoidea e.g. sea urchins 4.Class Crinoidea e.g. sea lilies 5. Class Holothuroidea e.g. Sea cucumbers 2.General characteristic 1)Radial symmetry(bilateral symmetry—larvae) 2)Triploblastic 3)Coelomate 4)Deuterostome 5)No segmentation 6)Spiny epidermis 7)Have a water vascular system in the coelom 3.Sea- Star body plan
1)ring canal—— radial canal 2)anus——Mouth on ventral side 3)Arm 4)Nerve ring 5)Tube feet 6)Madreporite 4.Echinoderm defence 1)Pedicellariae some asteroidea species) —modified spines with claws and capable of movement
—used to remove encrusting organisms 2)Ejection of intestines(some holothurians) —When startled some species will expel sticky tubules to entangle predators —May also discharge ad deadly toxin ----------------------------------------------------------------------(Phylum)Chordata 1.General charateristic 1.Maring, freshwater, terrestrial, aerial, subterranean 2.Bilaterally symmetrical 3.Triploblastic 4.Coelomate 5.Deuterostome 6.Partial segmentation 7.Reproduction —largely sexual and internal 2.Classification 1)subphylum: vertebrata e.g. amphibians,reptiles,fish,birds,mammals 2)Other subphylum 1)Urochordata—e.g. marine sea-squirts 2)Hemichordata—Marine’acorn-worms' 3)Cephalochordate—fish like lancelets 3.Notochord(defining feature of the chordates)
1)Notochord=stiff rod of mesoderm found next to the nerve chord in all chordate embryos(and some adults) 2)Functions as a endoskeleton(like a backbone) 3)Nerve chord located dorssally 4.Vertebrate —surround and protect the nerve chord
5.Cephalochordate —lack of jaws 1)lake jaws 2)earliest vertebrates shared this feature 3)later vertebrates developed jaws by modifying gill arches 6.Agnatha(jawless fishes, vertebrates) 1)496-360 million years ago—very diverse group of animals 2)early forms exoskeleton of bone in the skin(may even have had electroreception) 3)Now,only two small groups exist(lampreys and hagfish)
