Investigating the Effects of Temperature on the Rate of Respiration of Blowfly Larvae

Investigating the Effects of Temperature on the Rate of Respiration of Blowfly Larvae

This experiment was setup to investigate the effects of temperature on

the rate of respiration of blowfly larvae.

Background Knowledge

The maggots involved in this investigation were blowflies at the

larval stage of development, and they breathe through spiracles in the

anterior and posterior segments. The respiratory tracts are not as

developed at this stage, as the organism is not capable of flight, and

so it respires less oxygen than an adult blowfly. They feed on dead

organic matter.

The respiration of an organism involves an intricate use of enzymes,

and so some knowledge about them is necessary.

Enzymes can be described as biological catalysts, which alter the rate

of a chemical reaction without themselves being used up in the

process; thus they can be used repeatedly. Enzymes do not themselves

create reactions, just speed up reactions that would have otherwise

happened naturally.

Being proteins, enzymes have a three-dimensional structure. Within

this structure, a section is called the active site. It is within this

section that the reactions take place when the substrate molecules(s)

come in contact with it. (Substrate is the name for any molecule upon

which an enzyme has an effect.)

Enzymes sometimes become denatured. This is when a certain factor

affects the bonds holding the amino acids together, and they start to

break, eventually resulting in the enzyme unravelling.

Enzymes were, until recently, thought to work on the lock-and-key

hypothesis. This means that an enzyme has a specific shape of active

site, which would fit ex...

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...n in their bloodstream a substance which

acts like an anti-freeze, and so the blood of the fish continues to

flow, even though its temperature is below zero.

Due to their lack of thermoregulatory mechanisms, some ectoderms have

developed some interesting techniques designed to keep their body

temperature more stable. These include shuttling. This is performed by

lizards in the desert. It involves them lying in the sun and shade

alternately, so that their body temperature never raises or falls too

much.

Another technique is one by which when the ectoderm is too cold, it

lies perpendicularly to the sun, so that a higher proportion of its

surface area is being subjected to the suns heat. Conversely, when the

organism is too hot, it lies parallel to the suns rays, so that less

of its body is submitted to the suns rays.