1 / 22

Invertebrates 3

Invertebrates 3. Phylum Annelida and Phylum Mollusca. Branchpoints: Pseudocoelomate vs. coelomate Protostomes vs. deuterostomes. Aceolomates, Pseudocoelomates and Coelomates. Protostomes vs. deuterostomes. Fig 32.7. Major Protostome Phyla (traditional phylogeny). Phylum Annelida

idalee
Download Presentation

Invertebrates 3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Invertebrates 3 Phylum Annelida and Phylum Mollusca

  2. Branchpoints: Pseudocoelomate vs. coelomateProtostomes vs. deuterostomes

  3. Aceolomates, Pseudocoelomates and Coelomates

  4. Protostomes vs. deuterostomes Fig 32.7

  5. Major Protostome Phyla (traditional phylogeny) • Phylum Annelida • Phylum Mollusca • Phylum Arthropoda

  6. Phylum Annelida:The segmented worms

  7. Basic Annelida features • Have all features of coelomates and protostomes (know!) • Have body segmentation (new feature) • Repetition of body parts • Similar structures found in each region • Some specialization of regions • Some continuous parts (digestive system)

  8. Digestive system Complete Specialized regions Circulation Closed system Multiple hearts Gas exchange Body surface Coelom Excretory Metanephridia Body Plan (earthworm)

  9. Nervous system Cerebral ganglia (brain) Ventral nerve cord (fused pair of cords) One ganglion per segment Movement Peristalsis Setae Body Plan (cont.)

  10. Annelid diversity See previous diagrams • Earthworms • Marine segmented worms • Leeches

  11. Feeding in different classes • Earthworms • Earth suckers (create vacuum by expanding muscular pharnyx); lots left undigested • Process 40 tons of soil/acre of earth/year! • improve aeration/drainage • Leeches • Create vacuum by expanding pharynx, digestive tract • Blood suckers hang on with suckers, feed with jaws or have pharynx they stick into prey, suck out blood. • Secrete anticoagulants, vasodilators and numbing agents • Marine segmented worms • Wide variety of feeding modes

  12. Phylum Mollusca:The “soft-bodied” animals

  13. Protostomes, same branch as annelids. Evolutionary relationships

  14. Shell Mantle Visceral mass Mantle cavity With ctenidia Head and assocated sensory structures Radula Foot and epipodial tentacles Molluscan body plan (HAM)

  15. Digestive system complete note position of anus Circulation/Respiration ctenidium open circulatory system coelom=pericardial cavity. True coelom, but reduced. Water/ion balance and ammonia excretion Has paired nephridia: kidney-like in function Molluscan body plan (HAM)

  16. Molluscan body plan (HAM) • Nervous system • few ganglia at key locations, connected by paired ventral nerve cords. • have brain • several sensory structures (see description of HAM)

  17. Major Molluscan Classes • LEARN!: How is HAM modified for each of the major classes? ?

  18. Class Polyplacophora: “many plates” • The chitons • Differences from HAM • 8 shell plates • Expanded mantle cav. • Multiple ctenidia • Mantle grows over shell • Reduced head

  19. Class Gastropoda: “stomach-foot” • Representative members: Snails, limpets, abalone, nudibranchs, sea and land slugs • Differences from HAM • Undergo torsion (sketch) • What is torsion • Advantages of torsion • Disadvantages of torsion

  20. Class Bivalvia:“two valves” • Representative members: Clams, mussels and scallops • Differences from HAM • Two shells • Expanded mantle cavity • Enlarged ctenidia • Respiration AND feeding • Reduced head • Foot more elongate

  21. Class Cephalopoda:“Head-footed” • Representative members: Nautilus, squid, octopus • Differences from HAM • Shell reduced (pen in squid) • Foot gives rise to • tentacles • funnel • Mantle • Thickened and protective • Functions in movement • Nervous system highly developed • Great brain! • Eyes similar to vertebrates • Circulatory system closed! • Other features

More Related