Daphnia Magna Lab Report

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Pages: 9

INVERTEBRATE RESPONSES TO STIMULI
NAME : SHARAVANI SHANMUGANATHAN SANJEEVI
COURSE : BIOLOGY (SBI4U)

INSTRUCTOR : MS. PAULINE COLE
INSTITUTION : SUNWAY COLLEGE
DATE : 3 MAY 2016

Introduction
A physical description about the Daphnia Magna would be that these creatures has a body, shaped like a kidney bean, approximately 2 – 5 mm in size and being transparent. The body colour that this organism reflects is basically the colour of the food consumed by it. The transparent body is covered by a shell like structure is known as carapace. (Clare, J. 2002. ) The carapace elongates into the head, which has 2 long antennae , which branches of with 6 appendages within the carapace. This structure plays an important role as it produces current of
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The different reaction it portrays could be easily detected as its body structure is transparent. Some of the stimuli that could be detected easily through a Daphnia would be its heart beat , movement rate , nervous system and the phagocytosis process when food is present. These species of planktonic crustaceans applies an open blood circulation in its system. An open blood circulation in this species simply means the position of its heart is at the dorsal and anterior from the brood chamber . An average heartbeat of a normal Daphnia is about 200 beats at 20°C. This rate of heartbeat relies on the temperature, stating that when the temperature decreases, its heartbeat gets slower. ( Ebert,D.)
Daphnia’s have practiced absorbing the oxygen intake through a protein haemoglobin on the extracellular respiratory. Generally , each Daphnia is made up of four of these multi subunit haemoglobin (Hb) genes known as a multi macromolecule. An obvious red lining observed on the Daphnia has been specified as the area with the highest oxygen concentration as the oxygen is been stored in it. The oxygen haemoglobin concentration differs up to about 20-folds in response to the environmental change. (