Introduction Planarians are free living flatworms that are members of the class Turbellaria and phylum Platyhelminthes. Most are seen in fresh water environments, while others are found in large mosses, on land, and even in salt water. They are soft bodied, leaf-shaped, and ciliated animals that have two eyes, and a pointed tail. They have a mouth on the ventral side of their body often located half way to their tail. They typically grow between three and fifteen millimeters in length, and are a gray, brown, or black color. Planarians move by swimming, and some are relatively fast. Majority of planarians are carnivorous and feed on things like protozoans, small snails, and worms. All planarians are hermaphrodites, meaning that they contain …show more content…
both male and female reproductive structures in their bodies, and can reproduce in two way depending on their species. Most have reproductive organs that develop then cocoons of eggs that have been fertilized are laid. After this fully developed young planarians leave the cocoon and continue to grow and develop without going through metamorphosis. The other method of reproduction sometimes seen is when the planarian splits into two parts that will each grow and develop into a complete planarian (Britannica.com & Exercises for the Zoology Lab). These creatures are widely known for their ability to regenerate lost body parts. Much like how some reproduce, a planarian that has been cut in half with grow into two identical planarians from the two halves; meaning the tail section will grow a head and the head section will grow a tail. For this reason, they are often used in lab experiments like the one a lab class has recently participated in and completed. At the beginning of the experiment instructions were given by the TAs so that all involved had a basic understanding of what was expected to be done by the class. This particular lab as given and done as an assignment to observe and learn about the amazing regeneration abilities of planarians, and hopefully to see the full planarian regenerate itself from the part that had been cut off. Methods and Materials The instructions, methods and materials for this lab experiment were fairly simple and straight forward.
A person doing this lab experiment will need a planarian, a metric ruler, a small jar with a lid, enough distilled water to fill the jar about half to three quarters of the way, a transfer pipette, a petri dish, a location in either light or dark to keep it depending on what results the person might be looking for, a way to keep up with and record the measurements found, and a dissection microscope if possible. According to the handout of instructions given, the overall main goal of this experiment was to see if the planarian would or would not regenerate the head or tail at the same rate regardless of where the initial cut was made, and whether or not it was in the light or dark (Planarian Project: Procedure). For this lab students were instructed to pair off into partners, receive a planarian from one of the TAs, place the planarian in a dish, measure it to the closest millimeter, and then carefully cut it into two pieces at one of the three possible locations; behind the head, about the middle, or near the tail. The partners were then to pick one piece to keep and one to dispose of to observe over the next several weeks. (Planarian Project: …show more content…
Procedure). The first thing the groups of two were instructed to do was to gather all the materials needed to start the experiment.
After that, the lab partners were to uses a transfer pipette to carefully move the planarian from the jar of distilled water to the clean, dry petri dish. The next instructions were to put the dish with the planarian under a dissection microscope with a clear metric ruler to get a starting measurement to work with. After that, with the planarian still in the dish, lab partners proceeded to carefully cut of the head of the planarian, keep the body and tail section and gave the head to the TA. Finally, it was placed in a small jar of approved distilled water, that was around twenty-six degrees Celsius, with a lid that was partially closed, and then set it in a lit environment (on a desk located at the back of the classroom with an overhead lamp). Five days after the initial cut was made and original measurements were found and recorded, lab partners were to return to the lab every few days to check the progress of the planarian. In total, the planarian was checked and measured five different times over a period of nineteen days with the findings being written
down. Results Results from the experiment were quite interesting. Although information given had shown that the head or tail sections were supposed to grow back, it was still amazing to see that it actually happened. The results lab partners had gathered over the nineteen days showed very little change once the head had actually grown back fully. The starting day had the planarian at six millimeters in length, a grayish color, and in water that stayed around twenty-six degrees Celsius. It was difficult to get an accurate length measurement due to the almost constant movement it made, so after removing the planarian from the jar with a pipette and transferring it to the petri dish, if the majority of the water around the planarian was removed from the dish, the planarian moved less, and therefore it was easier to get a measurement. After the head had been cut off, the planarian measured around four millimeters in length. Five days later when it was checked and measured again, it showed to be around five millimeters and still did not have its head or eyes from where the cut had been made. Seven days later it was checked again and this time the head and eyes were grown back fully, and it measured to be around six millimeters once more. It was checked two days later and then four days after that still showing the same measurements of six millimeters, the same grayish color, and still showing quite a bit of movement. Discussion After looking back at the data gathered, and thinking about how the experiment was preformed, there were indeed things that could have been done in a way that could have resulted in something different than the results gathered from this specific experiment. One of these things is that if the planarian had been kept in the dark environment rather than the light one, the regrowth of the head might have happened at a slower rate. Another thing that could have provided more consistent results would have been if the data was taken with the same amount of time between each measurement. For example, if every two days at eleven o’clock in the morning the planarian was measured and other information recorded, it might have been easier to pinpoint when the head and eyes had actually grown back, and the overall results might have been more accurate. By doing this experiment, students were able to observe first-hand how quickly planarians can regenerate their head, body, or tail. Students were also able to learn how to conduct a simple experiment, and how to manage their time and schedules to allow for checking on and recording information about the planarian. Overall, by doing this lab experiment correctly, students could learn quite a bit about planarians, how they grow, how they look and function, and how to do an experiment.
Chapter 6: Mary Roach explains the use of cadavers for weapon experiments. Although it was sometimes ineffective for evidence evaluation scientist replaced them with animals such as pigs to receive better data. Changes like these were made to have more efficient experiments and have easier removal.
First, 100 mL of regular deionized water was measured using a 100 mL graduated cylinder. This water was then poured into the styrofoam cup that will be used to gather the hot water later. The water level was then marked using a pen on the inside of the cup. The water was then dumped out, and the cup was dried. Next, 100 mL of regular deionized water was measured using a 100 mL graduated cylinder, and the fish tank thermometer was placed in the water. Once the temperature was stabilizing in the graduated cylinder, the marked styrofoam cup was filled to the mark with hot water. Quickly, the temperature of the regular water was recorded immediately before it was poured into the styrofoam cup. The regular/hot water was mixed for a couple seconds, and the fish tank thermometer was then submerged into the water. After approximately 30 seconds, the temperature of the mixture leveled out, and was recorded. This was repeated three
Two members of the group were instructed to visit the laboratory each day of the experiment to water and measure the plants (Handout 1). The measurements that were preformed were to be precise and accurate by the group by organizing a standardized way to measure the plants. The plants were measured from the level of the soil, which was flat throughout all the cups, to the tip of the apical meristems. The leaves were not considered. The watering of the plants took place nearly everyday, except for the times the lab was closed. Respective of cup label, the appropriate drop of solution was added to the plant, at the very tip of the apical meristems.
The Daphnia magna species in this experiment were kept and preserved in jars of suitable water that acted as small ponds. Each Daphnia Magna was transported individually using a wide-mouthed pipette to a depression slide. The stability of the Daphnia Magna on the slide was attained by using a drop of pond water that acted as a boundary of movement for the Daphnia on the depression slide, small pieces of cotton wool were also used to act as an extra boundary to stop the Daphnia Magna from swimming in circles in the pond drop it was placed in; the stability factor was important in counting the heart beat rate more accurately. The depression slide was then placed under the stereomicroscope, over a cooling chamber that was used to slow down the
The use of model organisms in pre clinical trial is relied upon for the collection of safety and efficacy data prior to first in human clinical studies. The crustacean Daphnia magna is one model organism, whose heart rate is reported to react similarly to the human heart rate, when exposed to identical compounds (3).
In Labs 22 through 26, my lab partner and I were assigned a fetal pig to perform a dissection on in order to understand anatomy, the study of an organism’s structure1, and physiology, the study of the functions and activities of a living organism2. Throughout these labs, we studied the structure of the fetal pig and performed experiments to understand four system processes: digestion, cardiovascular, respiratory, and excretory. Dissecting an organism, physically moving and seeing the different portions of the organism, especially of a fetal pig, is very important. This helps in the understanding of the skeletal structure and what series of physical and chemical processes the mammalian species body performs in order to survive.
It was placed on a slide, a couple drops of water was placed on the slide to keep it moisturized. Next, we used a microscope to observe the heart beating in the transparent animal. According to the lab report on page 98 the normal heartbeats are about 350 per minute. By using a pencil and paper, we made a small dash for every heartbeat over a 15 second interval. Than we continued to repeat the observation of the heartbeats 3 more times for a total of 4 observations. We than totaled up the number of dashes and calculated the average of the four 15 second observations, this was labeled “Normal Heart Rate” on Table 1. Next we added 1 drop of an “unknown” solution that was assigned, we made sure to determine the average normal heart rate before doing do. The same procedure outlined above was conducted. The records were than placed in table 1. We than used water in replace of the unknown solution. The same procedure was conducted, we analyzed whether the Daphnia had recovered or not. Lastly our records were compared among our
Every student in a lab section planted eight seeds, two in each cell in a quad, to make sure that we had at least one plant for each week for 4 weeks. After planting the seeds we put the plants on a water mat tray to make
Teacher gave to us breain sheep that before were stored in a prevervative into solution. We put on the glaves and cut the braine in the good direction and make that in two pices where we can see all the parts that located to the braine.
Moreover, I will let the patient become familiar with any instruments such as a speculum, and demonstrate the tools that will be used to obtain tissue samples that would be used during the examination. Explaining the procedure is also a significant step; this will allow the patient have a sense of control during the examination as we ask and answer questions about their current state, that would help disseminate any concern they may have. Meanwhile, they can learn about what may happen, related to any body sensations or feelings they can experience during the procedure, all while the provider continues to develop rapport and patient’s trust
Works Cited "Animal Planet" Animal Planet. N.p., n.d. Web. The Web. The Web. 09 Apr. 2014. The 'Standard' of the 'Standard'.
We separated into groups of two each, making sure that we had the following materials for the lab: graduated cylinder, plastic sandwich bag, starch solution, twist tie, 500-mL beaker, iodine solution, and a pair of goggles and an apron (for the person handling the iodine solution).
Paleontologists had noticed the passageways inside the crest but had no way of knowing how intricate these tubes and chambers were until computers were used to scan the insides of the crest and differentiate between what was actual fossil and what was clay and sandstone. Computer Scientist Carl Diegert used a CT Scan (Computer Tomography, i.e.; CAT Scan) and scanned the skull at intervals of 3mm to produce 350 cross sections.
An improvement on this experiment could have been the watering; instead of twice a week, it could’ve been everyday and a consistent amount of water—maybe a set of up of sprinklers instead of hand watering the plants. Another improvement could have been a weed type plant guaranteed to grow, in order to better measure and collect results.
The first step was to obtain the White Rat and to tie it in the supine position, anterior surface facing up in side the dissection pan. To tie the animal, we used butcher’s twine and secured the front and hinds legs using a “lasso” technique, careful not touch the sharp claws. To make the first insicion I had to locate the Xifoid Process of the rat (distal aspect of the sternum). Once I had located the Xifoid Process, I had to use forceps to pull the skin of the animal’s abdomen up and use the scissors to cut. The first incision is made from stem to sternum, cutting through the errectos abdomen muscle down to the groin. The second incision ion is perpendicular to the first below the diaphragm. Because of this technique we were able to open the abdominal cavity first. The third and forth incisions were made bilaterally above the legs. The last two incisions were made in upside down “V” shape on the collarbone, to expose the thoracic cavity. This dissection was both sharp, because of the use of the scissors and scapel and blunt because of the use of the probe and forceps to move organs and skin to expose other organs not yet identified.