Planarians have a three-cavity digestive system. Planarians are usually either carnivorous or scavengers. Planarians may eat other living, as well as dead, invertebrates, detritus or decaying organic matter. Planarians do not realize that are eating a lot, and can over eat resulting in death. Most planarians are freshwater forms that can be found underneath dead leaves, rocks or logs. Planarians belong to the order Triadic.
Most species range from about 1/8 inch to 1 inch. There are different species which come in white, gray, black, brown and sometimes transparent. Planarians are hermaphrodites, meaning they have both female and male organs. They reproduce sexually but they cannot reproduce by fertilizing their own eggs with their sperm. Planarians can also reproduce asexually by regeneration. Planarians have become a vital model system for studying tissue regeneration and stem cell characteristics because of their quick ability to regenerate.
Studying planarians will build on our current knowledge in the fields of regenerative medicine and stem cell biology. Flatworms themselves are preyed upon by a variety of predators and are intermediate levels of the food chain, so they are important because they feed other animals. Hypothesis All three worms were cut in half. We had expected all the planarians to regenerate. The prediction made was the planarian that was the longest, would regenerate the quickest and begin to behave normally first.
Listed materials Seven clear Petri dishes Colored utensil to label Purified water Boiled eggs Tooth picks Fl ash light Measuring tape Paintbrush Knife Procedure 1. Obtain six Petri dishes 2. Put enough water into the Petri dishes to cover the bottom of all six 3. Label the three dishes with the colored utensil with three names of choice (We choose Chubs, Delia, and Carol) 4. Use a flashlight to test the response of the planarians and measure them 5. Feed the planarians with boiled eggs by using a toothpick to gather a very tiny amount of food 6. Record the data for day one 7.
Label the other three dishes with the names you choose but add a one to their name (Chubs 1, Delia 1, and Carol 1) 8. Place one planarian in each of the three dishes labeled with the original name with a paintbrush 9. Carefully slice the planarians in half with a knife 10. Use a paintbrush to move one half of the planarian into the matching named Petri dish 11 . Clean the water of the original dishes and refill with clean water 12. All planarians should be in clean water 13. Feed all planarians with a tiny bit of boiled eggs 14. Measure the length of all half planarians and record 15.
Test the reaction of the flashlight test on the planarians and record 16. Wash hands 17. Repeat steps 12-16 each day the planarians are observed and record Data and Observations Length of the Planarians in millimeters Chubs Chubs 1 Carol carol 1 Delia Delia I Starting(whole) 14 17. 5 5 Day 1 7 8 10 3 2 Day 2 (split in 2) Chubs 1. 5 4 13 Died Day 3 12 Day 4 6 Day 5 Day 6 Reaction to the flashlight stimulation Carol 1 Delia 1 Starting Moved toward the light Day 1-6 No reaction Based on our results, the planarians all died after our sixth day of observing them.
Chubs split in two after the first day but Chubs 1 died so we moved the second half of Chubs into a Petri dish and labeled him Chubs 1. 5. The longest over all (Carol) was actually the first worm to die completely by day four, including both parts. The worms that were mm long lasted the longest (Delia and Chubs 1. 5). On day five Delia was actually transparent on the half that she was growing back. It was interesting that Chubs split in half on day two, while the other part of him had died. Delia was the last survivor and almost the shortest worm, living till day six.
All the planarians reacted to the light the first day by moving closer to it, but after they were cut, none of the worms reacted at all. Conclusion It is important that we study such animals because more than half of planarian genes have parallels in people, and some of their basic physiological systems operate like ours. This could lead scientist into understanding how to regenerate human tissues or cells. If scientist learn how to achieve this than many different health issues could be solved, for instances diabetes.
This could also help scientist discover how to mutate the cells in other animals so they regenerate when they lose body ligaments in the wild. This could result in less deaths of animals and a lower extinction rate. Scientist do not study on humans because of their inability to grow back but one day hope to achieve this goal. The soft-bodied planarians move in a similar fashion as a slug. They use their foot to slither through a trail of slime, paving most of the slime behind. The planarian extends a tube-like pharynx from its mouth to reach for food.
Through this tube it secretes digestive juice onto its prey. The food is partially digested externally before it is sucked into the Castro vascular cavity where it is digested the rest of the way, and then diffused to the rest of the body. Without the pharynx, the digestive juice would not reach the food and it would not be able to ingest anything which would lead to starvation. The pharynx is a specialized organ that allows the planarian to find and take in food. Our worms were all cut the same way, but eave very different results.
The longest planarian parts died a lot quicker than the shorter pieces Of Worm. Concluding that our hypothesis had not turned out how we had expected based on our data results. A probable reason for the death of some of our worms could have been overfeeding them. Sometimes the chunks of egg was hard to get off, so we added more but then it all came out. Chubs 1 was over whelmed with food the first day, so he could have over eaten and died. Through performing this experiment, I learned many things about how regeneration works. Was amazed to see the planarians moving after they had been cut into two pieces.
I also enjoyed seeing how quickly the worms grew and regeneration does not take very long. Enjoyed this lab because it was very fascinating to see understand how a scientist could use regeneration to fix problems in the human. Do not enjoy seeing my worms die because they explode when they die and that made me sad.