Question

1. Address the following questions for the Porifera. Your answer for parts a-g (combined must not be fewer than 150 words. (35 points)
   1. Describe the basic body plan of a sponge. Include any distinctive features. The better answers will not fail to mention basic body form, situation with respect to symmetry, cell layers, mesohyl, osculum, pores (ostia), collar cells or choanocytes, maybe even spicules. 5 pts

2. How is a tissue defined? Do Porifera have tissues? If so, what tissues do they have? 5 pts

3. How is an organ defined? Do the Porifera have organs? If so, what organs do they have? 5 pts

4. About how many species of Porifera are recognized? Sources may differ quite a bit so use a reasonable source and cite it. 5 pts

5. In what kind of habitats are they found? (g., Saltwater? Freshwater? Terrestrial ? Etc.). Are they equally common in all habitats where they are found? Where they do occur, are Porifera free-swimming, attached to a substrate, crawling over a surface, burrowing, etc. ? What’s a “substrate” anyway ? 5 pts

6. Do sponges occur everywhere in the world that their habitat is found? Do sponges occur here in The Heart of It All (i.e., Ohio)? 5 pts

7. In Bio 202 lecture, Dr. Rauschert talked about energy flow in ecosystems and trophic levels. Where do sponges fit it here? Describe the basic ecology of a sponge. How does the anatomy of a sponge reflect its basic ecology? Dr. Rauschert also talked about symbioses. Do any sponges have interesting symbioses? (HINT: the answer here is a big fat “yes”, and it affects the answer about the trophic level of some sponges). 5 pts

Answer 1

a. The body of a simple sponge resembles a sac perforated with holes. – Water is drawn through the pores into a central cavity, the spongocoel, and flows out through a larger opening, the osculum. There are three different body plans found among sponges,

1. Asconoid- it is the simplest one. Here the spongocoel is surrounded by two layers the outer layer being pinacocytes and the inner layer being the choanocytes.  The spongocoel is lined with specialized digestive cells called choanocytes that filter and take in food.

2. Syconoid- In such forms ostia lead to a network of canals that are lined with choanocytes. Water is pumped into the Ostia and through these canals before arriving at the spongocoel. There are no choanocytes lining the spongocoel of synconoid sponges.

3. Leuconoid- most complex body plan. . In these sponges, the canal system forms a more elaborate branched network, and the canals lead to digestive chambers instead of a spongocoel. In leuconoid sponges, the choanocytes line the digestive chambers and not the canals. Once the r has passed through the digestive chambers it is released into an exit canal that leads to the osculum. There is no real spongocoel in leuconoid sponges.

b. The tissue is defined as a group of cells that perform a similar function and have a similar origin. The Poriferans are multicellular. However, unlike higher metazoans, the cells that make up a sponge are not organized into tissues. Therefore, sponges lack true tissues.

c. The organ is defined as the group of tissues that perform a similar function. As sponges cells are not organized into tissues so sponges do not have specialized organ grade body.

d. The Poriferans are simple multicellular animals. There are about 5000 to 10,000 of species of Porifera that are known today. Out of them, only 150 species live in freshwater. The rest of the sponges dwell in salt-water.

e. Sponges are simple invertebrate animals that live in aquatic habitats. Although the majority of sponges are marine, some species live in freshwater lakes and streams. They are found in shallow ocean environments to depths as great as five kilometres (km).

f. they may live almost everywhere, they adapt to the regions and surfaces they grow in. Yes in Ohio many freshwater sponges are found. As far as their history is concerned, complete sponges are relatively rare in Ohio rocks, although this may be in part because they are difficult to recognize.

g. Sponges are possibly primary consumers as a primary consumer is an organism that feeds on primary producers.

Sponges are critical components of the ecosystems of coral reefs, where they provide shelter for a variety of organisms including shrimp, crabs, and algae. They are also a source of food for many sponge-eating fish species. Many sponge species form large colonies or aggregates of individual organisms.

Sponges form symbiotic relationships with a variety of microorganisms, including bacteria and algae. For example, sponges living on scallops provide protection from starfish . Similarly, venus flower baskets consisting of glass sponges is given as a nuptial gift in Japan because the sponge symbiotically houses two small shrimps, a male and a female, who live out their lives inside the sponge.