Download Marine Mammals without a Backbone

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…
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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
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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/wat
ch?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
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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