Discussion:
In relation to the primary hypothesis, it was expected that D. magna offspring born in low calcium concentrations would have reduced growth and development compared to those in high calcium concentrations. This was looked at in regards to differences in overall size, days to hatching, and average growth rate of the offspring. Firstly, there was no significant difference between the eggs/offspring sizes in either treatment. According to, (McKee, 1997) maternal daphnia of the same population had low variability in intra-clutch offspring size and that the maternal body length does not relate to the size of the offspring. This would suggest that there is an ability to control fluctuating sizes of the offspring in relation to the genotype of the maternal population (McKee, 1997). Since all the daphnia from this experiment were clones from the same female, this could mean that the specimens all generally have similar offspring size. On the contrary, (Cleuvers et al., 1997) found that when low calcium concentration food was used, that the quantity of offspring produced was less
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The carapace acts as a pool that holds an accumulated amount of calcium, that is used when there is a demand for calcium as explained by (Hessen & Rukke, 2000). In this case, the spine, which is part of the carapace, may have been reabsorbed when the maternal daphnia reproduced, thus using the calcium of the spine to give to their offspring. Due to the lack of predators in the experiment, the maternal daphnia would not have needed the spine for predator protection and readily absorbed the calcium in the spine to pass on. In future experiments, the presence/absence of predators should be added to see if maternal daphnia readily reduce spine length in spite of the presence of predators in order to successfully
The Artemia franciscana can survive in extreme conditions of salinity, water depth, and temperature (Biology 108 laboratory manual, 2010), but do A. franciscana prefer these conditions or do they simply cope with their surroundings? This experiment explored the extent of the A. franciscanas preference towards three major stimuli: light, temperature, and acidity. A. franciscana are able to endure extreme temperature ranges from 6 ̊ C to 40 ̊ C, however since their optimal temperature for breeding is about room temperature it can be inferred that the A. franciscana will prefer this over other temperatures (Al Dhaheri and Drew, 2003). This is much the same in regards to acidity as Artemia franciscana, in general thrive in saline lakes, can survive pH ranges between 7 and 10 with 8 being ideal for cysts(eggs) to hatch (Al Dhaheri and Drew, 2003). Based on this fact alone the tested A. franciscana should show preference to higher pH levels. In nature A. franciscana feed by scraping food, such as algae, of rocks and can be classified as a bottom feeder; with this said, A. franciscana are usually located in shallow waters. In respect to the preference of light intensity, A. franciscana can be hypothesized to respond to light erratically (Fox, 2001; Al Dhaheri and Drew, 2003). Using these predictions, and the results of the experimentation on the A. franciscana and stimuli, we will be able to determine their preference towards light, temperature, and pH.
T. californicus is found from Alaska to Baja in small, shallow tidepools and tidal flats in the upper spray zone where they cannot avoid the full effect of visible and ultraviolet (UV) radiation. Individuals assemble in areas of lower radiation at midday, yet have no preference to the intensity of light at dawn and dusk (Hartline and Macmillan 1995). These tiny arthropods inhabit all types of marine sediments from sand to fine mud and ooze. Along with plankton, T. californicus eats microscopic algae, protists, bacteria, diatoms, algae and microbes (McGroarty 1958). When the concentrations of the species in their habitats are high, T. californicus will turn to cannibalism for a food source. The nautilus eye present in the species is rich with fatty acids and provides a good food source for the animal.
An Investigation to Show the Effect of Temperature on Daphnia Plan: I will submerge some daphnia contained in a test tube in water of differing temperatures and measure their subsequent heart rates. Hypothesis I think that the heart rate of the daphnia will increase up until around 40ËšC at which point most of the daphnia's enzymes will have denatured and rate of metabolism will have stopped or decreased sufficiently to have stopped the daphnia's heart rate. Apparatus list Test tube Beaker Different temperatures of water Daphnia Pipette Stop clock Microscope Slide Safety Follow usual lab safety rules. There are no major safety considerations in this experiment as the daphnia aren't harmful and water above 40ËšC will not be used. Method To determine if temperature does have an effect on the daphnia, I intend to carry out the following experiment.
The experiment can be improved by counting the number of eggs each gravid Artemia carries and the number of successfully born offspring to further support the hypothesis that the females fed on high nutrition have higher fecundity compared to the ones treated with low nutrition.
The North American brine shrimp goes through several stages in development before reaching adulthood. The brine shrimp is first encased in a protective capsule within a female brine shrimp’s brood sac (Drewes, C, 2006). Here, egg development rapidly...
We compared the untreated Daphnias’ data with the data of Carolina Biological Company. It was observed that the temperature plays a major role in increasing the heartbeat of the Daphnia, for example, at 10 degree Celsius it had the lowest heart rate
Fortunately, the assumptions made about maternal care in insects do not have to be accepted or rejected based only on faith or an educated guess; today it is possible for these predictions to be empirically tested so that the data may be recorded and analyzed. The following experiment is just one example of the various ways in which ideas regarding insects and maternal care may be effectively evaluated.
C. didactylus has 5 to 7, while B. tridactylus has 8 or 9 (BioMed Central, 2011). When compared to skeletons of related species to both sloths (e.g. anteaters and armadillos), none of the related species showed an unusual amount of cervical vertebrae. However, manatees have only 6 cervical vertebrae (Hautier, Weisbecker, Sanchez-Villagra, Goswami, & Asher, 2014). While all mammals need 7 cervical vertebrae to survive, it is remarkable to see these three species survive with their abnormal number of cervical vertebrae. As we discussed in class, having any more or less than 7 cervical vertebrae can be deadly to the organism. It is hypothesized that the low metabolic and activity rates of sloths protected them from the harmful effects from having an abnormal amount of cervical vertebrae (Varela-Lasheras, et al.,
Daphnis et Chloé begins in a meadow outside a sacred wood, where there is a statue of three Nymphs and a statue of the god Pan. Youths and maidens enter carrying open baskets of gifts intended for the Nymphs. The stage gradually fills. The crowd bows before the altar of the Nymphs. The maidens wrap garlands around the pedestals. Daphnis et Chloé begins with a religious dance. Daphnis enters, preceded by his flocks, and Chloé join him. They bow down before the nymphs and interrupt the dances. The maidens enter and flirt with Daphnis, which upsets her. She is drawn into a dance with you men, when another herdsman named Dorcon pursues her aggressively, which upsets Daphnis. They proceed to the general dance, which includes everyone. Dorcon wants
Artemia franciscana, known commonly as Brine shrimp, are aquatic arthropods within the animal kingdom who can readily adapt to extreme conditions. While they mainly live in saltwater lakes, such as the Great Salt Lake and the Caspian Sea, Artemia are able to survive in most inland saltwater excluding ocean (Gonzalo and Beardmore, 2012). Their main source of nutrition comes from Phytoplankton and microalgae: organisms that require sunlight to prosper. In addition, Artemia reproduces both sexually and through parthenogenesis, processes that require specific abiotic conditions for temperature and salinity*. In fact, Wear et al. (1986) states that higher temperatures are more effective in reproduction and maturation of Artemia. Primarily, this experiment is important for acknowledging the ecology of Artemia as well as their biodiversity in a time of climate change. Understanding habitat requirements is essential in aiding preservation, survival and reproduction.
Musick, John A. Biology of Sea Turtles. Ed. Peter L. Lutz. Boca Raton, Fla: CRC, 1997.
Phylogenetic relationships among the four Radix species are inferred based on their genomes and nuclear loci (Feldmeyer, 2015). Three different tests to infer selection and changes in amino acid properties yielded a total of 134 genes with signatures of positive selection (Feldmeyer, 2015). The majority of these genes belonged to functional genes including reproduction, genitalia, development, and growth rate (Feldmeyer, 2015). This studied showed that the Radix species divergence may be primarily enforced by selection on life history traits such as larval development and growth rate (Feldmeyer, 2015). The scientists hypothesized that life history differences may hint toward advantages under the according climate regimes, and they might have a fitness advantage with fast developing life stages, which are more tolerant to habitat changes (Feldmeyer, 2015). This study showcases that natural selection can act on the gene level and that certain mechanisms in the evolution of the organism can lead scientists to believe that it
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
1996). A study was done to examine the different parent-juvenile interactions of two different species of poeciliids: P. Monacha and P. Lucida. Individual females of the two species were place into chambers that had a mesh net to segregate it and allow juveniles to swim through and escape attack from the parent. The females were kept in these chambers as they birthed offspring and were recorded. It was found that the p. monacha females cannibalised their offspring immediately while the p. lucida females did not (Thibault 1974). The p. monacha juveniles that did escape the initial attack, swum to the bottom and through the mesh net. However, the juvenile p. lucida remained in the same section of the chamber with the female near the water
Osmoregulation is an example of an organism maintaining homeostasis. More specifically, osmoregulation involves an animal regulating osmotic pressure, or its fluid content. Brine shrimp, Artemia, use osmoregulation to regulate the saline levels of fluid within their body. Because brine shrimps live in seawater, an environment with a high saline concentration, they must actively excrete excess salt. Brine Shrimps use metepipodites as the location of the ion pump which secretes sodium. This is an active transport of ions because it is moving against the gradient, a higher salt content outside the body. The two following studies describe the environmental conditions ideal for brine shrimp and the possible genetic explanation for the osmoregulation of brine shrimp, respectively.