Daphnia Thermotactic Reaction

This lab was conducted with the purpose of confirming the trait of homeostasis among goldfish. During the experiment, it was recorded that the fish would increase gill movement when placed in colder water two out of the three trials. However, the results showed no significant difference in gill movement in various temperatures of water. This has very little effect on the broad field of science since our only three trials were performed and may have included human error in the trials.

This report presents the physiological changes in the heart rate of a fresh water crustacean Daphnia magna when exposed to caffeine and alcohol. Different Daphnia magnas were placed in a depression slide containing fresh water and later exposed to solutions of caffeine and alcohol. Each Daphnia magna had different responses. These data suggest there is an increase in heart rate when a Daphnia magna is exposed to caffeine and a decrease in heart rate when it is in a solution of alcohol.

At the conclusion of the experiment, the two hypotheses were reviewed. Because the water temperature did affect the normal respiration patterns of the goldfish, the null hypothesis was disregarded and the alternative hypothesis was accepted. From the results of this experiment, it was concluded that although other environmental factors could play

The purpose of this experiment was to determine the relationship between tail spine length and hemoglobin levels as well as the relationship between tail spine length and heart rate. The concentration of the hemoglobin in Daphnia is dependent on the oxygen available to them.

Daphnia, also known as water fleas, are small crustaceans about 1mm-5mm long and are part of the freshwater zooplankton (Ebert 2005, Hutchinson 2005 & Clifford 1991). Daphnia can be found in most fresh water habitats such as freshwater springs, ponds and reservoirs and are the predominant food for planktivorous fish. Dapnia are ‘filter feeders’ meaning they feed on small particles suspended in the water which can include algae. It has been found that daphnia tend to migrate to the upper parts of the water at night and return to the lower parts of the water in the day to hide from predators (Ebert 2005) (Hutchinson 2005). Daphnia can reproduce through sexual reproduction and also asexual

Referring to the experiment`s hypotheses that the A. franciscana prefers light, temperatures between 20-24 ̊ C, and a basic (pH 8) environment; the results regarding the first treatment, light, were initially vague. According to the experiment results, the A. franciscana did not show a clear preference towards light or dark because both sections contained high concentrations of them; the A. franciscana also strayed from the uncovered section. Several factors may shed light on the results such as the A. franciscanas physical appearance; they possess three light-sensitive eyes that can adjust to both low and high light intensities (Fox, 2001). This means that although they may prefer light they can survive in darker habitats as well; relating back to the experiment the A. franciscana may have been content with wherever they were, resulting in limited movement.

The differences in mean depth of Daphnia between the day and night could have been

Introduction: In the previous lab class, students did an experiment on a water flea known as the “Daphnia Magna”. The experiment consisted of locating the Daphnia’s heart and counting its heart rate. The heart rate is the number of times the heart beats per minute. The normal beats per minute in that the heart should endure is 60-100 BPM, (> 100 Tachycardia & <60 Bradycardia).

Daphnia usually eat algae and other small bacteria. They are filter feeders which allow them to eat because they are eating the bacteria that is found in the water as they filter it.

The experiment took place in a laboratory setting, and the first step was obtaining sixty individual Daphnia magna (that were neither adults nor tiny offspring) from a large tank in the lab. These individuals were equally divided into three groups; low density, medium density, and high density. The twenty Daphnia assigned to the low density group were split into four groups of five and pipetted into one of four tubes filled with 10mL of Chlamydomonas algae. The twenty Daphnia assigned to the medium density group were split into two groups of ten and placed into one of two tubes also filled up to 10mL with Chlamydomonas. The final twenty Daphnia were all placed into a single tube filled with 10mL of the algae. In order to avoid suffocation-related

DeVries and his colleagues originally went to Antarctica to study respiratory metabolism in fish but what he noticed was that when they caught the fish and put it in an aquarium at freezing point seawater -1.09, the fish survived except for some of the deepwater fish. When those fish touched the ice that formed on the cooling coils of the aquarium, they froze.

Daphnia are used to test water toxicity, they are a vital part of fresh water ecosystems. They are a food source for smaller fish and invertebrates and considered to be a consumer of algae and bacteria (Elbert, 2005). These small crustaceans range in size from 2-5mm long and are commonly referred to as water fleas. Daphnia belong to the group called Daphniidae, which is a relative of freshwater shrimp. It is easy to see the internal organs of daphnia because of a transparent taco shell like carapace. A carapace is the hard outer part of a shell or covering. A daphnia’s life span can range between 1-56 days. (Elenbaas, 2013; Clare 2002). The comfortable pH level for daphnia is between 7.2 and 8.5 (Clare, 2002).

Buddle and several other research scientists collected two-hundred specimens from their natural habitat to study their tolerance to cold and immersion in water. They found that like many other arachnids, the northern pseudoscorpion avoided freezing to death by lowering its body temperature. The northern pseudoscorpion had the ability to protect itself from temperatures as low as -7 degrees celsius. However, the real surprise came when they found that after an allotted time of seventeen days submerged in water, the pseudoscorpion was still alive. This astounded them considering that the typical flood time in their native habitat was seven days. The pseudoscorpions had a silvery coating around their bodies, suggesting that they had

An investigation into the effects of varying seawater concentrations on two marine invertebrates’ osmoregulatory abilities; Carcinus maenas and Arenicola marina.

There are 15 species of tuna in five genera comprising a monophyletic clade (Tribe Thunnini) of the family Scombridae. Tunas are highly active teleost predators that inhabit tropical and temperate waters mainly in the pelagic zones. Tuna are the only known teleost that can maintain its body temperature using thermo-conserving strategies. Relative to most other species, tunas have a fundamentally different swimming mode, a radically different thermal biology, increased rate functions (e.g. standard metabolic rate (SMR), aerobic capacity, heart rate and gut clearance) and a markedly different cardiac physiology. Thermoregulation is essential for maintaining high speed. These qualities are necessary for migration, feeding and foraging. In addition to thermoregulation, its unique composition of white and red muscle allows it to be so fast. The high proportion of red muscle in tuna allows it to swim at high speeds, up to 45km/h, for long periods without fatigue. ( Bushnell & Holland, 1997) The white muscle are used for short bursts of activity. (George & Don Stevens, 1978)