Orientation behavior is important in providing organisms with the highest chance of finding favorable environmental conditions and thus ensuring a higher probability of growth, safety and consequentially successfully mating and producing offspring (Hughes, 1989). Oniscus asellus, the common woodlouse, is a crustacean that requires humid habitats, commonly being found in rotting logs and under stones in Europe and the Americas. Consequently, orientation behaviours such as hygro-kinesis are to be expected (Hughes, 1989). Kinesis enables efficient relocation to more favorable conditions using simple procedural rules resulting in woodlice maintaining a straight line of movement rather than turning, even if obstacles block their path. As a result, it is hypothesised that woodlice, if forced to turn left, are more likely to immediately turn right afterwards, and vice-versa. This would increase the efficiency of the woodlouse moving away from an unfavorable area and thus decrease the average time until it finds a more favorable habitat (Hughes, 1967, Shafer 1972, Sutton 1972). Furthermore, the longer the time between turns, the lower the turning bias effect.
This experiment demonstrates this turning behaviour and tendency to move in a straight line as well as investigating the duration of this turning bias in an attempt to aid our understanding of how organisms maximize their probability of remaining in a suitable microhabitat.
Two experiments were carried out. One to test whether a turning bias was observed (Experiment 1 visible in Fig.1), and a second to investigate how time (Experiment 2a visible in Fig.2) and distance travelled (Experiment 2b visible in Fig.3) between turns affects the presence of a turning bias. All experiments used the same base maze system and the same pool of woodlice were used across all experiments although woodlice were not used multiple times for each experiment. Woodlice which took over 120 seconds to make the first turn or repeatedly turned around were discounted.
Experiment 1 saw woodlice placed in one of the starting points (A or A’ in Figures 1-3). An alley block was placed to prevent it moving forwards at intersection O creating a forced turn. Another was placed to prevent progression past intersection P. Whether the woodlouse’s turning direction at intersection P was the same as its initial forced turn direction was noted.
Experiment 2a was much the same as Experiment 1 but was simply repeated at each of the four intersections with alley blocks being moved and placed accordingly.
Experiment 2b again followed the same process as Experiment 1 except for the addition of a hold phase in the channel between intersection O and P. This phase involved the woodlouse being held in place by a paintbrush for 5, 10, 15 and 20 seconds on separate repeats.
A Chi square test of independence was calculated, with Yate’s correction applied, comparing the frequency of woodlice turning the same direction at P as at O versus those turning the opposite at P as at O. A significant interaction was found (X2 (1) = 153.372, p < 0.0001). Woodlice were significantly more likely to turn the opposite direction at P than the forced turn direction made at O in Experiment 1.
As Fig.4 shows, the turning bias effect demonstrated in experiment 1 decreases with increasing distance travelled. Initially 87% of woodlice followed the expected bias and turned the opposite way after 23mm (1 intersection in the maze). However, by intersection S, after 92mm, the turning bias was removed. In fact, 53% actually turned the same way as the forced initial turn.
Fig.5 shows a similar trend with turning bias reducing over time. Initially 82
Glucose Blood Regulation Processes
The process behind the regulation of blood glucose levels:
The endocrine system is made up of many different organs that secrete different hormones into the blood stream. The endocrine system works as a chemical messenger system within the human body, made up of all the glands that make hormones. These hormones are chemical messages that travel through your blood system to target the cells or organs to produce a prolonged effect. The purpose of the endocrine, is to keep the body in a homeostatic state constantly maintaining the internal conditions of the body. There are many glands which make up the endocrine as illustrated in the diagram below (figure 1). (Prime Health Channel, 2010)
Figure 1 (Bodytomy, 2018)
Each of these glands have a very special role within the endocrine system and all help the body to function at its optimum level and to keep the body’s internal environment stable and constant. The Hypothalamus functions as the control centre as it controls the release of major hormones through the pituitary gland as well as linking the nervous system to the endocrine.
This unit will focus on the pancreas and liver and how they work together to regulate the blood glucose levels of the body. This unit will also cover topics such as glucose regulation, how it is kept at a homeostatic level, negative feedback, how it works within the body when the blood glucose level needs to be maintained at a particular level as well as how the pancreas works in coordination with the other organs to achieve this.
Glucose is a monosaccharide sugar and the regulation of glucose is incredibly important as it is essential in preventing diseases like diabetes however the most important reason that glucose is essential to the survival of cells is that it is the key to cellular respiration. Cellular respiration is when glucose is converted into adenosine triphosphate which is also known as ATP this is a form of chemical energy which cells can then use, ATP is able to store and transport energy within a cell. (Grogan