Download Name Marine Biology--Mr. Nelson LAB: SPONGES AND

Name
Marine Biology--Mr. Nelson
LAB: SPONGES AND COELENTERATES
Introduction:
Sponges and coelenterates are simple invertebrate animals. Sponges make up the
phylum Porifera, which means “pore-bearing”. The phylum is named for the many pores that
cover the body of a sponge. Coelenterates are members of phylum Coelenterata (phylum
Cnidaria is also used). Hydras, jellyfish, and sea corals are types of coelenterates.
Sponges have no true tissues or organs, no digestive tract, and no nervous system. Their
bodies are loosely organized into two cell layers; the ectoderm and the endoderm. Support
comes from hard structures called spicules or from flexible protein called spongin. Spicules are
made of either calcium carbonate or silicon dioxide. Some sponges have both spicules and
spongin.
Coelenterates have true tissues. Their bodies consist of two layers; an outer ectoderm
and an inner endoderm. Between these layers is mesoglea, a jellylike material in which cells are
embedded. Each coelenterate has a body cavity, or gastrovascular cavity, where food is
digested. Coelenterates also have simple nervous systems that allow them to respond to
stimuli.
In this investigation you will examine the characteristics of sponges and
coelenterates.
PHYLUM PORIFERA:
The sponges are among the simplest of the multicellular marine animals. Their wellknown ability to absorb water is the result of numerous holes, pores, and chambers that
perforate their bodies. Sponges are sessile and are usually attached to hard substrates such as
rocks, pilings, or docks. Sponges are sometimes radially symmetrical but more commonly occur
as asymmetrical growths or encrusting masses (symmetry will be discussed in class this week).
Sponges consist of several types of loosely aggregated cells that lack the organization and
coordination found in higher multicellular animals. Water is circulated through the
central cavity, the spongocoel, to obtain suspended food and dissolved oxygen.
Procedure: All your sketches on this lab will have color and shading.
1. Sponge Structure: On the next page is a coloring sheet which shows generalized sponge
structure. Don’t do it now, but before starting the analysis questions, add the appropriate
colors to the sponge structure coloring sheet.
2. Sponge Skeletons: Some sponge skeletons, such as those of the commercial bath sponge,
consist of a flexible protein material known as spongin. Others have a mixture of spongin and
spicules. The spicules of sponges are composed of calcium carbonate (CaCO3) or silicon dioxide
(SiO2). Spicules are often difficult to see in a live sponge preparation, but they can easily be
isolated for better observation.
3. Obtain a prepared slide of sponge spicules.
Draw a few spicules under high power.
4. Using a regular (non-depression) slide and
cover slip, obtain a sample of sponge spicules
from Mr. Nelson. No air bubbles! Use the
microscope (lower light is best, I think)
and draw a few of the spicules,
under high power:
5. Wash and dry your preserved spicule slide. Leave it on your lab bench.
spnge structure coloring sheet here
Phylum Coelenterata (or Cnidaria):
The phylum Coelenterata includes a great diversity of uncomplicated yet versatile,
marine animals. Corals, hydras, sea anemones, jellyfish, and all other coelenterates are
characterized by radial body symmetry. Each possesses a centrally located mouth that leads to
a dead end digestive sac, the gastrovascular cavity. The mouth and surrounding tentacles are
capable of successfully capturing and ingesting a wide variety of marine animals for food. They
capture their prey with stinging cells, called cnidocytes, cnidoblasts, or nematocysts, which are
located all along each tentacle.
Coelenterates exist either as a free-swimming medusa (bell shaped) or as a sessile benthic
polyp (vase shaped). The oral end of the polyp, bearing the mouth and tentacles, is directed
upward. But in the medusa, the mouth and tentacles are oriented downward. Between the
inner and outer layers of the body wall is a gelatinous mesoglea. The mesoglea of most
medusae is thick and well developed, with a jellylike consistency that has earned them the
descriptive, if misleading, common name of jellyfish. Many species of coelenterates alternate
between a free swimming medusa generation and an attached polyp generation. In the life
cycle of a generalized coelenterate, polyps can produce medusae or additional polyps by
asexual budding. The medusae in turn produce eggs and sperm which, after fertilization,
develop into a new polyp generation.
The phylum Coelenterata consists of three classes;
Hydrozoa (Hydra and siphonophores which include the Portuguese man-of-war, Physalia)
Scyphozoa (the true jellyfish)
Anthozoa (sea anemones, corals, and sea fans)
Each of these classes is characterized by its own variation of the basic coelenterate life cycle.
Organisms in the class Hydrozoa usually have well-developed polyp and medusa generations.
The polyp generation is often colonial, with various individuals of the colony specialized for a
particular function. In the class Scyphozoa, the polyp stage is reduced or even completely
absent. This class includes most of the larger and better known medusoid jellyfish. In the third
class, the Anthozoa, it is the medusoid generation that is absent, and the sessile polyp form
dominates. Many anthozoans, such as corals and sea fans, are colonial, but some anemones
exist as large solitary individuals.
Class Anthozoa:
We will be looking at living representatives of this class. Anthozoan corals are much like
the fresh water hydra we will looking at today. The difference is that coral secrete a skeleton
house in which the polyps grow and they live in colonies. Corals are found in all seas, but the
reef-building corals are limited to tropical and subtropical waters that remain warmer than
200C. Other types of corals are found at moderate depths throughout the world ocean. The
calcareous skeletons of reef-building corals assume many growth forms depending on the
pattern of polyp associations.
Procedure: All your sketches on this lab will have color and shading.
1. Get a depression slide and have Mr. Nelson place a living Hydra on your slide. You will not
use a cover slip and you will be very gentle, as I will be using these Hydra with all my classes
over the next few days.
2. Use medium power (low power if it doesn’t fit) to sketch your Hydra. Inside your sketch,
include a measurement of the height of the organism (in um).
3. As your watching through the microscope, gently take a toothpick and touch the Hydra. Be
careful not to get the hydra stuck on the toothpick. BE GENTLE! How does the Hydras body
react?
4. Is this reaction an indication that Hydra have both nerve cells and muscle cells? Explain
5. Use high power to focus in on a tentacle.
Sketch a tentacle to include the cells that you see.
6. Return your living, undamaged Hydra to Mr. Nelson.
Get a prepared PhyasaIia tentacle from the lab cart.
Use high power to sketch an area of the tentacle
and include a cnidoblast (stinging cell).
Label the cnidoblast (s) on your sketch.
7. Now you will take a depression slide and ask Mr. Nelson for a Hydra viridissima. Sketch
this organism under low power.
7. Clean your slide and organize your area. When everything is ready, have Mr. Nelson check
your group out. This way you avoid being the “official class cleaner-uppers”
Analysis: Use your
this packet to answer
textbook, notes, and information in
the questions.
1. First, complete the
the beginning of this
sponge structure coloring sheet at
packet.
2. Sponges were
Kingdom Plantae.
that the Phylum
Kingdom and not the
originally classified into the
What characteristics necessitated
Porifera be classified in the Animal
Plant Kingdom.
3. What is the function of spicules?
4. What substances can the spicules be made of?
5. Sponges are another example of “filter feeders”. What is a filter feeder and what role do the
collar cells (choanocytes) play in this process.
6. Sponges can reproduce both sexually and asexually . Describe an example of each type of
reproduction as it occurs in sponges.
DID YOU KNOW?: The Coelenterates only have 1 opening in their digestive tract located at
the base of the tentacles. Therefore, food enters through the same opening as wastes are
expelled (I call it the mouth/anus)....YUK!!!!
7. Label the three body parts indicated on the Hydra diagram below, as either Digestive
Cavity, Tentacles, or Mouth/Anus:
use diagram from page 151 of lab 25
8. Give one function for each of the three structures you labeled in the previous diagram.
Digestive Cavity:
Tentacles:
Mouth/Anus:
9. Use Figure 8-5 to answer the questions below.
add figure 8.5
10. What is (are) the function(s) of a cnidocyte, cnidoblast, or nematocyst?
11. Looking at the picture above, describe how the nematocyst is fired.
12. Unlike the solitary Hydra, the coral are colonial organisms. What does this mean?
14. Which body type do the following Coelenterates exhibit as adults; Polyp or Medusa
a. Coral and Hydra?
b. Jellyfish?
15. Coral are organisms that produce a skeleton to live in. What is this skeleton house made of?
16. What function(s) does this skeleton adaptation provide to coral?
17. Using information in Chapter 13. Scientists predict that the ocean might become more
acidic, warmer and the sea level will rise as a result of an intensified greenhouse effect. How
might this affect coral reefs?
18. A symbiotic relationship is a close relationship between two different species in which one
species lives on, inside, or close to the other species and at least one species benefits from the
relationship. Review your drawing of Hydra viridissima. This species of hydra is a heterotroph
but it has the ability to utilize an additional source of nourishment. Living symbiotically within
the exterior tissues of this hydra are numerous unicellular, photosynthetic protists (called
zooxanthellae). What type of benefit(s) does this symbiosis provide to the Hydra?
--What benefit(s) does this symbiosis provide to the zooxanthellae?
19. There are three types of symbiotic relationships seen in nature:
*parasitism- one species benefits, the other is harmed by the relationship
*mutualism- both species benefit from the relationship
*commensalism- one species benefits, the other neither benefits nor is harmed by the
relationship
Based on your answer to the previous question, into which of the three types of symbiosis
would you classify the relationship between H. viridissima and zooxanthellae. Explain.