Exchange and Transport Systems - Dissecting Gas Exchange Systems

Question 1

Describe how to dissect fish gills in bony fish.

Answer 1

Make sure you’re wearing a lab coat.

Place your chosen fish in a dissection tray or on a cutting board.

Gills are located on either side of a fish’s head. They’re protected on each side by a bony flap called an operculum and supported by gill arches.

To remove your gills, push back the operculum and use scissors to carefully remove the gills. Cut each gill arech through the bone at the top and bottom.

If you look closely, you should be able to see the gill filaments.

Question 2

What are the ethical issues involved in dissecting animals? (2)

Answer 2

1) Some people argue that it’s morally wrong to kill animals just for dissections, as it is unnecessary killing. However, many dissections that are carried out in schools involve animals that have already been killed for their meat, e.g. fish.

2) There are some concerns that the animals used for dissections are not always raised in a humane way –
they may be subject to overcrowding,
extremes of temperature
or lack of food –
and they may not be killed humanely either.
If animals (e.g. insects) are raised in school for dissection, it’s important to make sure they are looked after properly and killed humanely to minimise any suffering or distress.