External gills usually have a higher surface area but they are less protected. In order to maintain the concentration gradient fish use the counter current system, so ensuring as efficient gas exchange as possible. This is because they can increase their alveoli numbers, and their method of gas exchange does not depend on the size of their bodies; only the alveoli. In humans, the diaphragm expands and contracts so inspiration and expiration occur. Heamolymph is the name of the liquid insects use to transport substances. Insects, however have a tracheal system that takes the gases directly to body cells allowing for more rapid transport than fish and mammals, and this means that insects have the higher metabolic rates needed for their active lifestyles. Hey i was wondering if someone could give me a mark for this exellence essay.

Could someone take a look at my gas exchange essay? It doesn’t seem that people posting their essays have been taught this structure and I’m starting to wonder if it is necessary although I do trust my teacher is right. Because of the pumping action required for the insects’ gas exchange system it is only effective over short distances, and the size of a locust is limited. The water flow over the gills is opposite to the direction of the blood supply. In order to conserve water both insects and mammals have internal gas exchange systems which protects them from the outside air, and this makes them well adapted to terrestrial living. Some good points here at the end. To reduce the energy cost of this process, capillary arrangement enhances gas exchange.

Is this all correct? I know that some text say that the gills are external BUT in the exam avoid using this term numerous folds……. Insects In insects e. While the points you make are correct they are common sense and are not at a yr 12 biology level so would not help you get merit or excellence.


Better to compare things like: Hi Maria H Having a look at your info on earthworms Teeth increase SA of food for enzymes in our stomach to work on.

The water keeps gas exchange surfaces moist as this is an exterior gas exchange system. However, they are internal for fish with internal gills. It is restricted in its pressure due to the fact that the fragile gill gas exchange surface would rupture if the pressure is too high.


Also, is it wise to memorise the Achieved ‘description’ part of the Essay? Adaptations of a fish Description: Earthworms have a small nutritional nccea energy requirement.

They both digest cellulose! Fish In bony fish eg salmon gas exchange occurs as such: Insects, however have a tracheal system that takes the gases directly to body cells allowing for more rapid transport than fish and mammals, and this means that insects have the higher metabolic rates needed for their active lifestyles. The suitability of the system is dependant on exchanfe and metabolic activity of the organism. The lamellae provide essayy adequate surface area for edsay gas exchange.

The gas exchange surfaces have a semi permeable membrane to allow diffusion of gases. Locusts and other flying insects also have air sacs which help force the air along the tubes, and oxygen naturally diffuses into the tracheal system. This size difference results from the large number of bacteria in the cecum of herbivores, which aid in the nccea breakdown of plant materials such as cellulose. Oxygen dissolves in the liquid at the end of the tracheoles, and moves across a diffusion gradient into the muscles while carbon dioxide diffuses out.


The haemolymph is pumped through the heart and then flows back around the body diffusing through the ostia back in the heart. One more special feature of annelida is – their skin contains mucus glands which produce large amount of mucus.

ncea gas exchange essay

In an open circulatory system, the tissues and organs receive nutrients by direct contact with the hemolymph which means that the insect will have a high percentage of body that is fluid. It is kept moist exchangr mucus secreting cells, which is important because oxygen dissolves in the fluid.

Gas Exchange – WGHS BAP Year 12

The sizes of the gas exchange systems of these three animals differs according to their body size and metabolic rate. The main features of insect gas exchange are: Whearas in the cow grass is first ingested into the rumen where microbes provide the enzymes necassary to breakdown cellulose in the grass. INSECTS Locusts and other insects have a gas exchange system that delivers exchnge directly to the muscles, bypassing a blood system that carries oxygen like humans have.

For efficient absorption a large thin membrane surface is required.

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For example you say “The earthworm So is the humans discussion alright then? These materials diffuse in and out of the cells. Here, oxygen diffuses into the blood as carbon dioxide diffuses out.

ncea gas exchange essay

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