Sexual Selection Lab
***START OF PAGE 1*** 1) Hypothesis [2 marks] |An isopod’s body length and speed affect its chances of predator avoidance. | 2) Plausible reason why/how each independent variables affect the dependent variable. [2 marks] |An isopod’s body length, specifically if it is short, will allow it to move faster. If an isopod has low speed it will not likely avoid predators as | |much as an isopod which moves fast. | 3) Prediction(s): [2 marks] If an isopod’s body length and speed have an effect on its chances of predator avoidance, then some traits will be better adapted to the environment | |and as a result, would increase the isopod frequency and those traits will be passed on to subsequent generations. | 4) Null Hypothesis: [1 mark] |Body length and an isopod’s speed have no affect on its chances of predator avoidance. | 5) Prediction of Null Hypothesis: [1 mark] If an isopod’s body length and speed have no affect on its chances of predator avoidance, then there will be no change to frequency since those traits | |will not be passed on to subsequent generations because they provide no advantage in regards to fitness and predator avoidance. | 6) Results and Conclusions: a) Figures 1 (for size) & 2( for speed): Inserted on page 2. [7 marks, 3. 5 marks per figure] b) Isopod length and success against predation: [3 marks] |The mean average for isopod length in the initial population is 12. 8mm. The mean average for isopod length in the survivor population is 13. mm. The | |selection intensity is 1 mm. There is a slight shift towards longer isopods. Looking at the figure 1, the isopods with a body length between 12. 1 mm- | |15. 0 mm produced the most survivors after predation. Surprisingly, those with a body length between 15. 1mm-18. 0 mm initially had a low population, but | |after predation, they had an increased number of survivors. Taking this into account, my hypothesis was incorrect because the longer the body length, | |the increase number of survivors you will observe after predation. | ) Isopod speed and success against predation: [3 marks] |The mean average for isopod speed in the initial population is 0. 91 cm/s. The mean average for isopod speed in the survivor population is about 1. 28 | |cm/s. The selection intensity is 0. 37 cm/s. There is a slight shift towards faster isopods in the surviving population. Looking at figure 2, the | |isopod’s who had a sprint speed between 0. 0 cm/s – 0. 05 cm/s had the highest amount of predator avoidance in the survivor population. Yet again, the | |isopods who had a sprint speed between 2. cm/s and 3. 0 cm/s had an increased number of survivors (> than initial population). Also, those isopods who | |had sprint speeds between 1. 6 cm/s and 2. 0 cm/s had the same rate of survivors as the initial population. Analyzing these results, my hypothesis is | |somewhat correct because those who ran the fastest (0. 0 cm/s – 0. 05 cm/s) produced the highest number of survivors after predation. | ***END OF PAGE 1*** ***START OF PAGE 2*** [pic] Figure 1. Frequency distribution of isopod body length prior to and after being exposed to a black spoon as the predator.
Figure 2. Frequency distribution of isopod sprint speed before and after being placed on a plastic race track and measuring its speed on an interval of 10 seconds. ***END OF PAGE 2*** ***START OF PAGE 3*** 7) Primary Literature Search: a) Citation: [1 mark] |1. Zidar, P. , Hribar, M. , Zizek, S. & Strus, J. Behavioural response of terrestrial isopods (Crustacea: Isopoda) to pyrethrins in soil or food. Eur. J. | |Soil Biol. 51, 51-55 (2012). | b) Relevance to lab experiment: [1 mark] |Discusses changes to an isopod’s behavior when exposed to different environment.
Might explain why the isopods behaved a certain way in the lab. | 8) Communication (TO BE COMPLETED BY YOUR TA) [2 marks]: Your TA will evaluate your assignment as follows: |Poor (0. 5) |Average (1) |Good (1. 5) |Excellent (2) | |Poor syntax, grammar, sentence | | |Excellent syntax, grammar, sentence| |structure and flow throughout. Some issues with syntax, grammar, |Minimal issues with syntax, |structure and flow throughout. | |(…It is very difficult to |sentence structure and flow. |grammar, sentence structure and |(… Everything is clear, concise, | |understand what you are trying to | |flow. |and easy to read. ) | |say. ) | | | | Final Mark: _______ /25 ***END OF PAGE 3***