The purpose of this experiment was to see if caffeine had an effect on the heart rate of Daphnia (water fleas) by observing them under the microscope and recording their heart rate over a period of time in concentrations of caffeine. Caffeine, which is a stimulant drug rttused in coffee, tea, Red Bull and Pro-plus, causes increased amounts of stimulatory neurotransmitters to be released. As caffeine is a stimulant, a prediction was made that caffeine would increase the heart rate of the Daphnia.
Method
To conduct this study a culture of living Daphnia were collected from a nearby natural water source area.
A light microscope was set up with the light on a low setting; one large Daphnia was selected and placed in the centre of a cavity slide by using a pipette.
The Daphnia and the cavity in the slide was surrounded by a ring of cotton wool, this restricted the movement of the Daphnia making it easier to count its heart rate under the microscope.
No cover slip was used as it would have damaged the water flea and stopped its oxygen supply. Before placing the slide under the microscope, a tissue was used to remove the pond water around the Daphnia and with a pipette plain water was added to the cavity slide.
As soon as the water was added a timer was set for two minutes and the slide was placed under the microscope.
Steadily adjusting the controls on the microscope the Daphnia was made visible and the heart was located through its translucent body.
As soon as the two
This experiment is to see The Affect of Caffeine on Daphnia. Daphnia is also known as a water flea. It is a distant relative of crabs and shrimps. (Marshall Cavendish, 2002) Daphnia have a hard external skeleton with jointed appendages and limbs. The head contains a large central eye which is made of two eyes joined together. Daphnia has two pairs of antennae which are used for swimming. Each daphnia has five pairs of limbs. These limbs lie in a certain space under the body bounded by the carapace. (Marshall Cavendish, 2002) A carapace is a hard upper shell or chitinous outer covering on the back of some animals. The daphnia is well preserved because of its shells which are composed of chitin. The usual size of this microorganism is about 0.2-0.3 mm; they look like flat disks. Their bodies are divided into three parts – head, thorax, and abdomen. The head is typically dome-shaped with five pairs of appendages. Among these five are two pairs of antennae; there is a small pair and a larger pair. The smaller pair of antennae serves as a sensory function and the larger one is used for swimming. The other three appendages’ purpose is to secure food they intake. (Michael Hutchins, 2003) The thorax holds four to six pairs of legs that are used for gathering food, filtering water, or grasping mates. There are over 400 species of daphnia and they are distributed worldwide. Daphnia uses their thoracic legs to produce a constant current of water; this allows them to filter food
To perform this test, a small drop of water is placed on a clean microscope slide. A metal loop that has been properly sterilized in the blue flame and allowed time to cool is used to
Due to the miniature size of a Daphnia, biologists have had unique troubles with analysing the way the systems of the Daphnia function. Biologists have argued, that the circulatory system of a Daphnia relies on diffusion or convection. However, it has been decided that depending on the oxygen levels in the environment will affect the way that the circulatory system of the Daphnia functions. The levels of haemoglobin will also affect the functioning of the circulatory system in the water flea. Haemoglobin is a red blood cell, assisting the
Using the microscope provided to analyze the different size of the different cells and organisms
The materials needed for this lab were: a light microscope, lamp (if needed or available), microscope slide, coverslip, tweezers, preserved insect leg (or a parakeet’s
My hypothesis was supported in the experiment due to the fact that caffeine raised the beats per minute, while kava drastically decreased the amount of heart beats in a given minute. By looking at figure 1 you are able to see that kava decreased the heart rate by -46 beats per minute, while the caffeine raised the beats to 26 per minute. This supports the conclusion that the stimulation humans receive off of caffeine has a similar effect in Daphnia Magna. Caffeine raises the beats per minute in each individual, while kava decreases the amount of beats. This is due to kava’s relaxation properties found within it’s roots commonly called kavalactones. I assumed that the effects of caffeine and kava on humans would be similar to those of Daphnia
The purpose of this lab is to insure that all students understand how to correctly use the microscope. Students will all learn proper care and handling of the microscope, as well as learning the correct way to look at slides and specimens through the microscope.
We could see that is was transparent and observed movement inside the specimen. We could see a green circle inside the specimen. Specimen #2
According to Ebert (2005), Daphnia magna are a species from the arthropoda phylum and are crustaceans. Daphnia are very small organisms, with males being smaller than females, found in standing freshwater sources around the world. These water sources can be in any area or environment, except for the extreme cases, like a hot spring. They have 10 flat, leaf-like appendages used to help them swim and filter water and materials. Their bodies are surrounded by an uncalcified shell, which can be thought of as a soft membrane. Daphnia have a transparent body, therefore it’s easy to see their heart, located dorsally, and the brood chamber which may contain eggs. Their heart in generally beats at about 200 bpm. It also is easy to see their blood due
Problem: An unknown bacteria in test tube #13 needs to be identified out of the list of bacteria provided as possible. Hypothesis: If different tests were carried out to identify the bacteria’s characteristics, then the bacteria could be identified, because a dichotomous key can be used to eliminate all other bacteria in the list Procedure: 1. Obtain an inoculating loop, Bunsen burner, test tube #13 and a test tube rack. 2.
Observation of phenotypic appearance was taken using a dissecting microscope at 50x magnification and a
The purpose of this lab was to introduce students on how to properly use a compound binocular microscope to observe organisms. Additionally, learning how to find the size of the field of view and organisms was part of the purpose of this lab. There were two lab observations made, one finding the diameter of the field of view for each magnification and observing three organisms underneath the microscope. Upon entering the lab for the clear ruler observations, it was hypothesized that if the ruler was able to be clearly seen and measurements taken on the 40x magnification then it would be able to be seen and estimated for all magnifications. That was proven incorrect. The higher magnifications made the field of view so small on the ruler that an accurate measurement could not be taken. The ruler was measured under 40x, 100x, and 400x magnification. First, the ruler was measured under 40x magnification and had a diameter across the field of view of about 4.5 millimeters. The fit number was converted to 4,500 micrometers. When the magnification increased to 100x magnification, the field of view decreased to 1.8 millimeters in diameter.
pathologist to zoom in on different parts of a slide and pan around the slide on the
Place a small piece of bibulous paper over the smear. Saturate the paper with malachite green.
This process was repeated for the other two prepared slides. The onion slide was prepared by cutting the onion in half and then half again. A slice of onion was taken and gently cracked in half to reveal a thin clear sticky layer. This thin layer was placed on a slide before adding a drop of iodine. The slide was placed under the microscope and observed on all three magnifications.