Experiment Design
Porifera have an uncanny and mostly unexplained ability to regrow cells to heal wounds. Not only are Porifera incredibly resistant to damage done by their environment, but to mutilation as well. Their regenerative abilities allow for any piece of sponge, made up of more than just choanocytes, to eventually reform into a new sponge. The experiment I have designed should be the first step in identifying why they are able to do this. The experiment is designed to show which class of Porifera, Hexactinellida (glass sponges), Calcarea (calcareous sponges - having spicules), Demospongiae (demosponges), and Scleropongiae(coralline or tropical reef sponges), is the most and least adept at recovering from physical damage. That information could then be used to contrast the two classes, structurally and genetically to find the root cause.
Materials:
The experiment will test the ability of each class of free standing sponge's speed and ability to regenerate. The same species will be used in every class to maximize accuracy. Every sponge should be the same age and similar size and body type. The control group will be subjected to every variable except the damage to make sure there are no outside influences and what is being tested is directly the sponge's ability to regrow. One also must be sure to follow every precaution in caring for sponges.
Steps:
Independent Variable: Number of days
Dependent Variable: Amount that regrows/unimpeded filtering
Hypothesis: I predict that the Calcarea class will regrow the fastest, because this class is unique in it's spicules, which should strengthen the overall structure and keep the sponge more hardened and densely compacted. I think having this will make it harder for damage to compromise filtering function, and the firmness of the formation will give the sponge more of a template to grow back into.
Possible Findings: Hopefully there would be a clear time difference between the classes, with one clearly healing first and another clearly healing last. This would allow for a more targeted look into why Porifera are able to express this uncanny ability, looking at the differences between the most successful and the least successful. Even if they all perform marginally the same, that shows that this is an intrinsic trait essential to Porifera's survival, which makes it even more curious. Another secondary finding this experiment could reveal is simply how much damage can the average Porifera withstand? According to the video below, a lot more than in my experiment, but it would be interesting to see. I would suggest performing both forms of the incisions, it would give a wider range of results. I put the simple diameter cut first because I assumed it would do less damage, so you could see if doing a more damaging cut would be completely useless or not. But it occurred to me that maybe cutting around most of the diameter would actually be more structurally compromising than sacrificing some surface area. Would one cut be better for one class and the other better for another? Also having the removed piece opens up many more tests one could do, seeing how long it would take that to form a full sponge. Would the reformed sponge be Identical to the original? These are all possible results, and there are many more.
Materials:
- 20 of each class of sponge as a control group
- 20 of each class of sponge as an experimental group
- 160 2.5 gallon tanks
- Detritus to feed sponges
- A small surgical blade
- Tape measure
- Receptors to measure levels of detritus
- Waterproof non-damaging highlighter/paintbrush different from the color of the sponge
The experiment will test the ability of each class of free standing sponge's speed and ability to regenerate. The same species will be used in every class to maximize accuracy. Every sponge should be the same age and similar size and body type. The control group will be subjected to every variable except the damage to make sure there are no outside influences and what is being tested is directly the sponge's ability to regrow. One also must be sure to follow every precaution in caring for sponges.
Steps:
- Set up every sponge in their environment
- Feed each sponge the same amount of detritus at the same time
- Measure sponge vertically and horizontally, convert lengths into percentages
- Start incision in the middle of the sponge going horizontally
- Use the edge of the tape measure to cut steadily
- Cut 90% of the sponge's diameter
- Clearly color the insides of the incision
- Color some of each sponge in the control group with the highlighter/paintbrush to make sure it's not damaging
- Measure the percentage of color every day
- Also measure the levels of detritus consumed daily to the levels of detritus fed each day (or however often its should be fed), to see if sponge function is compromised. Also do the same with the control group, to make sure fluctuation in detritus intake is not due intrinsically to the different classes.
- If every sponge has healed and/or results are unclear:
- Cut a square out of each sponge with an area of 4cm and a perimeter of 4cm (each side 2cm), making sure it's the same surface area on each sponge and mark the borders of the incision with the highlighter/paintbrush to see where the regrowth begins.
- Do everything the same way but with that variable
- Could also test the removed piece of sponge's ability to form a new sponge
Independent Variable: Number of days
Dependent Variable: Amount that regrows/unimpeded filtering
Hypothesis: I predict that the Calcarea class will regrow the fastest, because this class is unique in it's spicules, which should strengthen the overall structure and keep the sponge more hardened and densely compacted. I think having this will make it harder for damage to compromise filtering function, and the firmness of the formation will give the sponge more of a template to grow back into.
Possible Findings: Hopefully there would be a clear time difference between the classes, with one clearly healing first and another clearly healing last. This would allow for a more targeted look into why Porifera are able to express this uncanny ability, looking at the differences between the most successful and the least successful. Even if they all perform marginally the same, that shows that this is an intrinsic trait essential to Porifera's survival, which makes it even more curious. Another secondary finding this experiment could reveal is simply how much damage can the average Porifera withstand? According to the video below, a lot more than in my experiment, but it would be interesting to see. I would suggest performing both forms of the incisions, it would give a wider range of results. I put the simple diameter cut first because I assumed it would do less damage, so you could see if doing a more damaging cut would be completely useless or not. But it occurred to me that maybe cutting around most of the diameter would actually be more structurally compromising than sacrificing some surface area. Would one cut be better for one class and the other better for another? Also having the removed piece opens up many more tests one could do, seeing how long it would take that to form a full sponge. Would the reformed sponge be Identical to the original? These are all possible results, and there are many more.