Marine Mammals without a Backbone Marine Biology: Chapter 7

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

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

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

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

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

The Awkward Part.. Asexual reproduction Sexual 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

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

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

Cnidarians Coelenterates Sea anemones, jelly fish, corals Radial symmetry

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

Hydrozoans Hydrozoans Siphonophores 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

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

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

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

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

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

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

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

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

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!!!

Segmented Worms Annelids Consists of segments 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

Polychaetes

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