Phylum Cnidaria

Warm up 4/4

1. What is biomass?

2. Why is there more biomass in lower trophic levels compared to higher trophic levels?

3. Explain the 10% rule.

4. What is the role of decomposers and detritivores?

Phylum Cnidaria

EQ

Draw the external and internal features of an anemone (through a dissection )

What kind of animals represent Cnidaria?

Jellyfish, anemones & corals represent phylum Cnidaria.

They exist as either individuals or colonies.

What body plans do Cnidarians have?

Two forms – medusa form and polyp form

Medusa form – free-swimming jellyfish

Polyp form – stuck to rocks, anemone looking

One species of jellyfish has achieved immortality by switching between these two stages

https://youtu.be/Z7d5P0pDVUo

Polyp vs. Medusa form

Features of cnidarians

Nematocysts – stinging cells on their tentacles, used to capture food

Radial symmetry – body of an organism is repeated in a circular manner, like a pie

Nematocysts firing

https://youtu.be/7WJCnC5ebf4

Role of cnidarians in an ecosystem

Cnidarians are secondary consumers

They eat zooplankton and other small fish

Also important to build habitats for other species (coral reefs)

They also participate in many types of symbioses

https://youtu.be/vNhORnwcQcU

How do cnidarians feed/get rid of waste?

Cnidarians reel prey in when caught in their tentacles, like a fishing line

Cnidarians do not have an anus, so digested waste comes out of the mouth of the organism

Pretty gross… Be glad you aren’t a coral/anemone

Basic external anatomy of cnidarians

Basic internal anatomy of cnidarians

Anemone dissection

Reserve two pages of your notebook.

Split both pages into two halves, top and bottom.

One half will be a drawing of the external anatomy of the anemone looking directly from the top down, the other will be a side view of the external anatomy.

Another half will be the internal anatomy of the anemone. The last half page is reserved for post lab questions.

Title for your table of contents: Anemone Dissection

Anemone dissection

Rules:

Do not throw the anemone

Clean up after yourself (clean the tools you used, clean the tray you used, wipe your table)

Follow all instructions on the lab guide

Failure to follow these rules results in a 0 for the lab.

Anemone dissection

1. Group reading of the first page of the lab guide

2. Draw external anatomy (top and side view)

3. Label external anatomy (use picture on the lab guide to help you identify structures)

4. Follow the lab guide’s instructions to ensure a clean dissection.

5. Draw the internal anatomy

6. Label the internal anatomy

7. Clean up (dispose of anemone in trash, dispose of gloves, rinse equipment in bathrooms, wipe table down with Clorox wipes)

8. Answer post lab questions and discussion

Post lab questions

1. What is the basal disk of the anemone used for?

2. How does an anemone feed? Describe this in as much detail as possible.

3. How does an anemone dispose of waste?

4. What kind of cnidarian body plan does the anemone have? How do you know?