this is my investigation processed so far.could anyone pro have a look at my investigation to see if anything needs improving?
titile page: the effect of light intensity on the distribution of helice crassa.
Introduction: the ecological niche of Helice crassa: Helice crassa belongs to biological class Malacostraca(1). The helice crassa studied were found at Tohuna Torea estuary at the end of Riddel Road.they were usually found under the mud covered by the sea water,in dark damp conditions.so that they are not exposed to high light intensity.because they are prone to dessication.many adaptation features help them reduce the effect of dessication.these include:
1.helice crassa tend to move close to the dark place but move away from the light area. Because high light intensity is often associated with large amount of heat. –biology individual animal study helice crassa: mud crab Mary Melrose department of education Auckland 1988
2. Large pincers-this helps scoop up mud so that they can burrow to shelter from searing heat which is associated with high light intensity. the behaviour of two estuarine crab species by C.G..BEER, department of zoology,university of otago,new Zealand.(received by editior,April 15,1958)
3. the impermeable exoskeleton,strengthened with calcium carbonate,protects the crab from desiccation in air.
http://www.seafriends.org.nz/enviro/cru ... htm#Helice
living under the mud often covered by the sea means cooler temperature,damp condition,low light intensity,im going to investigation the preferred light intensity of helice crassa which is the best light intensity which helps reduce the effect of dessication.
Aim: the purpose of this experiment is to find out wether or not the number of helice crassa burrowing into the mud changes with increasing light intensity.
Hypothesis: the number of helice crassa burrowing into the mud increases with increasing light intensity.
(reason:high light intensity is often associated with a large amount of heat, if an increasing number of helice crassa burrowing into the mud is found,then high light intensity would have an effect of the amount of dessication)
Null hypothesis: the number of helice crassa burrowing into the mud remains the same with increasing light intensity
(Reason: if high light intensity has no effect on the amount of desiccation then helice crassa will not show any responses to the increasing light intensity)
Equipment: 30 helice crassa.
3 ice cream containers
Paper to mark
Mud-6 cm deep(the same percentage of mud as well as sand)
Method: 1.go down the riddel road to collect 30 helice crassa.
2. Put mud (6 cm deep) into each ice cream container, the percentage of mud and sand remains constant in each ice cream container.
3.seperate 30 helice crassa into three groups with each group(10) put into each ice cream container.
3.cover the first ice cream container with a piece of wipe,then cover the second ice cream container with 2 pieces of wipe then the third ice cream container with 3 pieces of wipe.
4.measure the light intensity in each of the ice cream container.record light intensity in a table
5.after 5 minutes covered by the wipe, uncover it to count the number of helice crassa that has burrowed into the mud.
6.record the number of helice crassa burrowed into the mud against different light intensity.
according to the experiment with Helice crassa is looks well to me and the details too. you have te record all the changes and their etiology (crab's) and alos i think you have to read some more materials about physiology of crabs becsase they are different from other arthropods because the the chitina that they have allover their body. They stay in dark areas because they insticts sent them for protection.
I hope that i give an understanable answer.
Hi, I'm Karole, and I want to know what you mean by helice crassa is 'different from other arthropods because of the chitina'.
What is chitina? Do you mean chitin? And even so, don't all arthropods have it?
Also, is having chitin all over the body mean that the mud crabs have exoskeleton all over their body?
Is it a physiological adaptation? I'm looking for any physiological adaptations of helice crassa that reduces desiccation. By the way, I'm doing this research assignment for water content of the mud that helice crassa lives in.
im doing my research on the effects (on the weight of the helice crassa) of different salinities. i have searched everywhere but i cant find any general knowledge about the helice crassa and any adaptations of the crab related to the range of salinities and how it effects their weight, to help introduce my investigation. Any suggestions?
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