Cladogram worksheet

Sorry for the bad handwriting.  This is why I normally type assignments up...  Just in case, I will retype the answers below...

1. Multicellularity.

2. Scyphozoa and cubozoa.  They are on their own branch.

3. No, only scleractinians.  Because calcium carbonate production appears at the scleractinia branch.

4. Rhopalium.

5. Anthozoa.  The polyp body form as an adult is what separates class anthozoa, so all the orders within anthozoa have it.

6. Tissues. Nematocysts.

Scyphozoans and Cubozoans Compared, Using 3D Models

For this project, I created 3D models of a True Jellyfish (scyphozoan) and a Box Jellyfish (cubozoan) using Tinkercad software.

The True Jellyfish (Scyphozoan) has a medusa body plan.  It has a round bell, tentacles attached at the margin or edge of the bell, and oral arms attached further in surrounding the mouth.  It's gonads are the ring shaped structures in my model. It also has rhopalia, which are sense organs that can detect light and dark,  and up versus down.

The Box Jellyfish, or Cubozoan, has a somewhat different anatomy.  Its bell is square when viewed from top or bottom. Its tentacles are attached to the corners of the square by structures called pedalia.  There can be one tentacle, or many, attached to each pedalium.  Cubozoans also have sense organs called rhopalia, but theirs are more advanced than those of scyphozoans.  They have some rhopalia which actually look like an eye, though others are more simple.  In addition to light and dark and up/down, they can distinguish colors, although they do not seem to see white well.  They avoid things that are red.

Here is a video of me explaining the models:

Scleractinia 3D Model

This is a 3D model of scleractinia (hard coral) which I built using Tinkercad software.  Scleractina produce calcium carbonate skeletons, which is what coral reefs are built out of.  

Anatomical features are labelled in the first two images.  One polyp is shown with a cutaway of part of the corallite so the polyp and septa are more visible.

My model is an example of a scleractinia colony, showing two polyps.  Each polyp in an individual organism, but they live together in a colony.  

Corallites are the calcium carbonate skeletons that each polyp creates.  Each corallite has separate walls.  Inside the corallite there are ridges called septa.  Each septum is sandwiched between two layers of mesentery tissue, which secrete the calcium carbonate that forms the skeleton of the coral.

Polyps are joined together by a layer of living tissue called the the coenosarc, which covers the coenosteum (skeletal tissue which connects the corallites).

Here is a video of me showing the model in 3D:

Mushroom Corals: A Dichotomous Key for 3 Main Genera

1.
 A: If oral disk is smooth------------------------------------------------------Discosoma
 B: if oral disk is not smooth-------------------------------------------------2

2
A: If oral disk is covered with rounded, bumpy tentacles---------------Ricordea

B: If tentacles are not round, and there are many pseudotentacles------Rhodactis

Zooxanthellae/Coral Symbiosis

This diagram shows a section of a polyp, with zooxanthellae, and shows their symbiotic relationship. The coral will only grow in sunlit areas, so the zooxanthellae can photosynthesize. The coral provides protection with its tentacles, and carbon dioxide, a waste product for the polyp, but vital to the zooxanthellae for photosynthesis. The zooxanthellae, in return, give the coral oxygen, necessary for animal life, and nutrients, giving the coral nourishment when it cannot find prey.