Sponges can be divided into seven different parts--ostia, oscula, internal cavity, choanocytes, amoebocytes, mesohyl, and epidermal cells. Keeping these parts in mind will simplify the process of drawing a sponge.
Click each row in the table below to focus on each step in the process of drawing and labeling a diagram of the sponge shown in the image to the right.
| Step 1: Internal Cavity | First, draw a shape that resembles the sponge in the image that is on the top of this page. Be sure to include the large opening at the top. Draw this shape so that it looks like a chunk is missing. This will allow your diagram to include a good view of the inside and cross section of all of the cells. Label the hollow space in the middle "internal cavity." |
| Step 2: Ostia and Oscula | Label the large openings at the top "oscula." Draw little openings on the outer surface of the sponge and label them "ostia." |
| Step 3: Epidermal Cells | Draw some flattened cells on the outer surface. Label the outer surface cells "epidermal cells." |
| Step 4: Choanocytes | Draw some cells that look like a head attached to a skirt with a tail coming out of it. Label these "choanocytes." Be sure to draw them with flagella facing outward toward the internal cavity. |
| Step 5: Amoebocytes and Mesohyl | Draw some blob-like shapes sandwiched in between the layers of choanocytes and epidermal cells. Label these "amoebocytes." Label the space left over in the amoebocyte layer "mesohyl." |
Click the activity button below to access the Drawing Porifera worksheet. On this worksheet, you will draw and label a diagram of the sponge in the image at the top of this page. When you have completed this worksheet, submit it to your teacher.
