jellies and sponges PDF

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jellies and sponges...

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Station 1 Phylum Porifera Cole Museum Case 3 and G6 15-20 min

A glass sponge Euplectella and Glass Rope Sponge. Glass sponges are members of the class Hexactinellida, which means six-rayed. Go and look at the sponges in case 3 which have other examples. The station includes microscopes with some glass slides with Hexactinellida spicule preparations. ● ●

Look at these. What is the function of the spicules? Support and protection from predation Look at the spicules and compare to those in station 2. Are they all the same size and shape? If not, why do you think that is? How many rays do they have?

Your answers: No, they vary. Many have 6 rays. The different sizes and shapes are to provide good structure of the sponge in varying areas of the body. So in some places it would be appropriate to have long spicules and in others to have short ones. Station 2. G6 Calcareous sponges 15-20 min

This station has specimens Leucosolenia (asconoid), Grantia compressa and Sycon (syconoid). All three body types are found in this Class of sponge. ● ●

Look at the diagram to look at the differences in complexity. What is the difference between the two body types found here?

Here you would be expected to look at the diagram that is given and see how the asconoid is much simpler than the syconoid, with only one layer of choanocytes. ● ●

Look at the slide preparations. What are the spicules made from? Calcium carbonate

Station 3 – G6 and Case 3 Class Demospongiae 15-20 min

This class of sponges contains 95% of all sponge species. All these sponges are leuconoid. Look also in Case 3. ● ● ● ●

Have a look at Euspongia slides. These show something different from spicules. What do you think the structure you drew is made from? Spongin, aka collagen What does Eu mean? True

Station 4. G6 Class Scyphozoa 20-30 min

Here we have the common moon jelly fish Aurelia, found washed up on UK shores. You can choose to look at this or the slides, or both if you prefer. ●

Draw a specimen. Use a hand lens or magnifying glass if needed. Referring to the diagram on the table, see if you can identify these in your specimen. Only draw what you see.

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What life stage are you looking at and what are the other life stages that are found in this phylum? Medusa. Also found are the polyp and the planular larva – a diagram is provided.

Station 5 Class Hydrozoa 10 min

LIVE HYDRA Live Hydra have been placed in a drop of water in a watchglass. Observe its behaviour under low magnification – do not turn on the light as it will kill the animal. In a pot next to the microscope is a pot of small crustaceans. Add one to the watchglass and observe the behaviour of the Hydra. What happened? Station 6 Phylum Cnidaria 20 min

LIVE ANEMONES Spit on your finger and wipe across the top of a cover slip taking care not to cut yourself. Allow to dry. Now take the cover slip using forceps, very gently, and place it against the tentacle of one of the Anemones. Gently pull it away and place on a slide saliva side down. Using a compound microscope, try to see whether the Anemone discharged any nematocysts. . They will look like long threads. If you find one, put it under high magnification and draw it. If you are successful please let the demonstrators know. Cole Museum Cases 3, 4 and 5 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●

Case 4. The Portuguese man o’ war Physalia is a free-floating colony of the Class Hydrozoa. These colonies are heteromorphic zooids that cooperate to meet the colony’s needs. What are the different functions of the different zooids? Some for defense, some for digestion, some for reproduction etc. Case 3. What does the word “Porifera” mean? Pore bearer Case 4. What is the name of the flagellated cells seen in sponges? Choanocytes Case 3. What is the name of the central sponge cavity? Spongocoel central cavity Case 3. What is the name of the large opening at the top of the sponge? Osculum Case 4 and 5. Jellyfish are traditionally placed which clade, which refers to their body symmetry? Radiata Case 5. What is the phylum name of a coral and what does it refer to? Cnidaria – stinging cnidae Case 4. Jellyfish have what tissue layers and are filled with what? Mesoglea Case 4. Why are Ctenophores grouped together with Cnidaria? Both apparently have radial symmetry Look at the board next to case 1. Where do the animals in cases 3-5 sit on the tree of life? What Cnidarian classes are in cases 4 and 5? See case How do the animals in case 5 relate to the animals in case 4? These are corals, Anthozoans and are in the same Class as the sea anemone. What does the name Cnidaria refer to? Stinging cells called cnidae or nematocysts Why are the corals mostly white? Bleached, having lost their symbionts, zooxanthellae...