A level biology

Results suggest that the directional movement of the Calliphora is influenced by the angle of light and that the maggots showed negative phototaxis behaviour. This supports work which was carried out by previous researchers. This response of moving away from the incident light may offer the Calliphora larvae increased chance of survival.

Larvae of the Calliphora species demonstrated negative phototaxis when illuminated with incident light radiation. Taxis is an orientation movement towards or away from a light stimulus. Negative phototaxis is the movement away from a light stimulus. In this investigation the maggots were kept in the same conditions and were placed individually into the experimental area. The maggots were then illuminated in light from only one direction and there response was observed. The vast majority of the

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Experimental results

To measured the rate of movement in cm/second this meant having to measure the distance moved and the time taken for each 2 second interval and using the following equation

Speed = Distance

Time

Associated results

The associated results are measurements taken to ensure that the variables of this investigation were being controlled.

Humidity The humidity I have found out does have an effect of the maggots behaviour, but the changes in humidity during the experiment will be minimal and the maggots behaviour wouldn’t be effects very much

Temperature The temperature does change the rate of activity in the maggots, the change in temperature was kept to a minimal and there wasn’t a huge change in temperature during the whole experiment this shouldn’t have an effect on the maggots behaviour.

• My null hypothesis has to be change because of the new criteria:

There is no relationship between the distance the maggot moves and the distance the maggot is away from the light. If they were to increase their rate of movement and or change the direction of movement with light intensity (a kinesis), should they be on the surface, or reach the surface they would make themselves more vulnerable to predators. This kind of behaviour would be too easy for predators to spot, although it stops when the organism is buried deep enough to be an advantage to them. This behaviour has survival value for the maggot as bright light include ultra violet rays (UV).

Chemical traces Although I had problems with this in my preliminary work, I found that there were no visible effects from the chemical traces, if there were it would only be a small amount this wouldn’t have affected my results.

Common topics in this essay:
O-E O-E, UV UV, O-E2 O-E2, Calliphora Vicina, Implementing Modifications, Pupating Description, Average Lab, Abstract Research, Larvae Calliphora, Larvae Analysing, negative phototaxis, negative negative, negative negative negative, towards light, phototaxis behaviour, light intensity, intensity light, light stimulus, maggots behaviour, steps minimise, chemical traces, negative phototaxis behaviour, 6 8 10, maggots moved light, 4 6 8,

Approximate Word count = 4489
Approximate Pages = 18 (250 words per page double spaced)

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