Marine Mammals without a Backbone

1. Marine Mammals without a Backbone Marine Biology: Chapter 7

2. Lets Get Started… • Kingdom Animalia • Organisms of this kingdom must hunt/find their own food • Two major groups; • Vertebrates: have a backbone • Invertebrates: lacking any backbone • At least 97% of all species of animals are invertebrates

3. Suspension vs. Deposit • Suspension feeders- animals that eat food particles suspended in the water • Filter feeders • Deposit feeders- animals that eat detritus that settles on the bottom • Detritus- dead “stuff” which sinks to the bottom of the sea-floor

4. Sponges • Sponges do not form true tissues and organs • Among the structurally simplest organisms • Sponges are sessile • Come in all shapes, sizes, and colors, but all have a relatively simple body plan • Phylum Porifera; “pore bearers” • Contain numerous tiny pores, or ostia

5. Sponge Anatomy • Pinacocytes- flat cellson the outer surface • Porocytes/pore cells- allows water to enter • Choanocytes/collar cells- uses a flagella to create a current and trap food particles • Osculum- water exits from this point • Spicules- support structures (siliceous/calcareous) • Spongin- skeleton of tough elastic fibers • Amebocytes- secrete spongin and spicules

6. So what’s it look like?? http://www.youtube.com/watch?v=RmPTM965-1c

7. The Awkward Part.. • Asexual reproduction • Branches and buds of the sponge break off and grow into separate sponges • Sexual reproduction • Produce gametes, large nutrient-rich eggs and smaller sperm cells that have flagellum • Broadcast spawning- sperm are released into the water and enter a sponge containing eggs

8. Growing Up! • Early stages of development occur within the sponge • Larva is released into the water • Carried by currents until it settles on the bottom and develops into a cute tiny baby sponge

9. Just a little more… • 6,000 known species of sponge • Mostly inhabit shallow tropical waters • Branching, tubular, round, volcano-like • Encrusting- thin growths on rocks/dead coral • Glass Sponges- anchored in deep-water, have lace-like structures • Boring Sponges- bore channels in CaCO3 • Coralline Sponges

10. Cnidarians • Coelenterates • Sea anemones, jelly fish, corals • Radial symmetry

11. Body Parts • Tentacles- finger-like extensions to collect food • Gut- food is digested, connected to the mouth • Nematocysts- stinging structures • Polyp- sessile stage • Medusa- upside down polyp adapted for swimming • Planula- Larva, consisting of 2 layers of cells • Epidermis- 1 of the two layers, the outer part • Gastrodermis- Internal layer, lines the gut • Mesoglea- gelatinous middle layer

12. Hydrozoans • Hydrozoans • Wide range of forms • Many consist of colonies of tiny polyps • Do not always consist of a polyp stage, and some lack a medusa stage • Siphonophores • Drifting colonies of polyps • Portuguese Man-O-War

13. Scyphozoans • Scyphozoa • Larger jellyfishes, with larger medusae • Planktonic- easily carried by currents • Have a bell-shaped ‘head’ • Swim with contractions of the bell • Some of the most dangerous marine creatures

14. Anthozoans • Anthozoa • Solitary/colonial polyps that lack a medusa stage • More complex than hydrozoans or scyphozoans • Septa- within the gut, used for support and help with digestion • Sea anemones, corals

15. Corals • Calcium carbonate skeletons • Tropical waters • Gorgonians- Secrete a tough branching skeleton (Sea fans) • Precious Corals- gorgonians with red/pink spicules as well • Black Corals- Secrete a hard black protein skeleton • Black and precious carved into jewelry

16. Feeding and Digestion • Almost all are carnviores • Capture and digest food larger than that of filter feeders • Use their nematocysts primarily to capture prey

17. Behavior • No brain or true nerves • They do have specialized nerve cells • These cells interconnect to form a nerve net that transmits impulses in all direction • Statocysts- Small calcareous bodies in fluid-filled chambers surrounded by sensitive hairs- give them a sense of balance

18. Worms… • Bilaterally Symmetrical • Anterior • Posterior http://www.youtube.com/watch?v=deDNgChc_7I

19. Flatworms • Platyhelminthes • Have a central nervous system where information is stored processed • Have a SIMPLE brain- just an aggregation of nerve cells in the head • More complex tissues than that of cnidarians • Turbellarians- free living carnivores • Flukes/trematodes(largest group)- parasites • Tapeworms/cestodes- parasites, looooong body

20. Ribbon Worms • Nemertea • More complex degree of organization • Have a circulatory system • Proboscis- a long fleshy tube used to entangle prey

21. Nematodes • Also known as roundworms • Hardly ever seen, but are often found in sediments • Many are parasitic • Small with cylindrical bodies which are pointed at both ends • Feed on bacteria and organic material • Sushi- OH NO!!!

22. Segmented Worms • Annelids • Earth and marine worms • Consists of segments • The gut goes through all the segments and lies in the cavity known as a coelom • Polychaetes • Closed circulatory system • Have gills

23. Polychaetes

24. Polychaetes • Trocophore- band of cilia around the body, larval stage • Live in temporary or permanent tubes