Basic biology and classification of marine invertebrates

1. Basic biology and classification of marine invertebrates

3. -Metazoan animal origins: 700 million to 1.4 billion ybp -Cambrian explosion: 600 mybp -evolution is not progressive, no increase in complexity after origination of phyla -many body plans are no longer around -What caused the dramatic radiation of metazoans?

4. Burgess shale fossil quarry in the Canadian Rockies

8. Some major phyla of marine invertebrates Porifera sponges Cnidaria jellyfish, anemones, corals Annelida segmented worms (e.g. polychates) Mollusca clams, mussels, octopus, squid Bryozoa bryozoans Arthropoda crabs, shrimp, copepods, Echinodermata urchins, holothuroids, sea stars Urochordata ascidians/tunicates You should know the phyla and examples and general characteristics of animals in each

9. Some basic terms: Benthic vs. Pelagic Sessile vs. Mobile Solitary vs. Colonial Sexual vs. Asexual Encrusting vs. Upright Autotrophic, Chemoautotrophic, Heterotrophic Predation, Herbivory, Omnivory, Primary production

10. Phylum: Porifera: Sponges -simplest multicellular animals, but not ancestral! -no true tissues -cells are independent and perform specialized functions -very efficient filter feeders -good spatial competitors -incurrent and excurrent canals -asymmetrical

11. Sponge anatomy-built around a system of pores, chambers, and canals -choanocyte -spicules

12. Phylum Cnidaria jellyfish, anemones, corals What makes something a Cnidarian? -all are aquatic -tissues present but no organs -2 basic shapes or phases: polyp & medusa -nematocyst -tentacles -1 opening

13. Phylum Cnidaria jellyfish, anemones, corals Cassiopia Physalia: man-o-war

14. Phylum Cnidaria jellyfish, anemones, corals Hydroid Sea Pen

15. Phylum Cnidaria jellyfish, anemones, corals Solitary reef coral Colonial reef coral Anemone Sea fan

16. Phylum Annelida Class Polychaeta segmented marine worms Fire worm 6000 species Segmentation Setae A variety of feeding modes: Active predators, mucus bag feeders, mud-munchers and passive filter feeders

17. Feather duster worm -serpulids: secrete CaCo3 shell -filter feeders Christmas tree worm

19. Phylum Mollusca Class Gastropoda: snails and limpets Cassis Cyphoma -second most diverse marine animal phyla (100,000+ species) -no segmentation -have complete gut -usually have a calcareous shell Class Polyplacophora chitons

20. Phylum Mollusca Class Gastropoda: snails and limpets Cone shell Conus geographus “mini melo” -many predatory snails are highly specialized

21. Phylum Mollusca Bivalves: clams, oysters, mussels, scallops Tridacna Giant Clam -some have autotrophic symbionts -most are active filter feeders

22. Phylum Mollusca Cephalopods: octopods, squid, nautilus Octopus-8 arms Squid-8 arms + 2 longer tentacles

23. Phylum Mollusca Nudibranchs: sea slugs -most are specialized predators Aplysia Sea Hare

24. Phylum Bryozoa: bryozoans -passive filter feeders -colonial -zoids

25. Phylum Arthropoda Subphylum Trilobita Subphylum Chelicerata horseshoe crabs, sea spiders Subphylum Crustaea crabs, shrimp, barnacles, copepods Subphylum Uniramia insects -by far the largest animal phylum -could represent several independent phyla -mono vs. polyphyletic -all are segmented, but segments are divided into different body regions -appendages are paired and jointed -all have an external skeleton -probably derived from annelids

26. Phylum Arthropoda Subphylum Chelicerata horseshoe crabs, sea spiders

27. Phylum Arthropoda Subphylum Crustaea crabs, shrimp, barnacles, copepods

28. Barnacles (goose neck) Blue crab

29. Phylum Echinodermata Sea stars -radial symmetry

30. Phylum Echinodermata Diadema Sand dollar Pencil urchin

31. Phylum Echinodermata Ophioroids (brittle stars) Crinoids

32. Phylum Echinodermata Holothuroids Sea cucumbers

33. Urochordata ascidians/tunicates