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– 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– 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– 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