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AP Biology: Behavior Lab!
Sehlah Khalidon 9 October 2012
Transcript of AP Biology: Behavior Lab!
The experiment with the Drosophila melanogaster Organisms respond to stimuli (anything that can be sensed) that are important to their survival. This response to stimuli, or taxis, depends on the sensory and motor abilities of an organism. In this investigation, the chemotaxis, or movement of an organism in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance, of the Drosophila melanogaster, or the fruit fly, was being observed and tested. Drosophila melanogaster were placed in a chamber (two water bottles attached to each other where the bottom parts are cut out) where at one cap of the chamber a cotton ball sprayed with vinegar was placed, and at another cap a cotton ball sprayed with water was placed. These two cotton balls introduce many stimuli in the investigation which affect the chemotaxis of the fruit flies in the chamber. Furthermore, these stimuli will then allow classifying the fruit flies’ behavior as innate (inherited and instinctive) or learned (as a result of the animal’s experience through the environment and other organisms). Conclusively, the data used from classifying the fruit flies’ behavior and chemotaxis, will help identify natural selection within this environment. Background Information! Hypothesis:
If the fruit flies are placed within an environment with more than one stimulus, then the fruit flies’ behavior will change as a response to those stimuli, and will indicate a sign of natural selection over multiple generation.
( Strategies for testing hypothesis)
1. Introduce a new control group that is placed in a plain chamber.
2. Use that control group to compare the normal behavior of the fruit flies and their behavior as a response to stimuli in a chamber where there are cotton balls sprayed with water and vinegar.
3. One member of the group will look at one end of the chamber and another member will observe the other end. The final member will observe both ends to further develop observations.
4. Breed several generations of fruit flies and identify natural selection related to the behaviors and chemotaxis of the fruit flies. For example, the fruit flies that are most suited to their environment, their traits will be most prevalent in the next generation.
5. The environment pressures and genetic makeup controls the phenotype of the fruit fly. Therefore, in the investigation, the phenotypic frequencies must be observed. Procedures:
1)Sketch an illustration of fruit flies in your lab notebook and label the anatomical structures. Are you able to differentiate between the males and females?
2)Not able to place 1 piece of masking tape on the outside of chambers on a behavior tray because experiment was done on fruit flies.
3)Place one to two drops of vinegar and water on separate cotton balls.
4)Use anesthetize on the fruit flies in order to calm them down, before placing them into the chamber.
5)Carefully observe the fruit flies for about 10 minutes. For every minute for 10 minutes, count the number of organism in each chamber and record observations in Table 1.
6)Document and record the behavior of the fruit flies.
7)Calculate the average number of organisms in each chamber in the 10 minute period of time, and then add the results to table 1.
8)Calculate class average for the number of organisms in each chamber in a 10 minute time period.
9)Calculate standard error and deviation.
10)Using the class data; draw a graph and discuss whether results are different between empty chambers and vinegar chambers.
11)Compare whether there were significant differences between organisms.