A Little Bit More
As I worked on the unit poster and focused on the need for tunas to swim continuously just to breathe, I soon realized that constant action to maintain breathing isn’t all that unique. If you think about it for a moment, it’s obvious that we too must actively breathe continuously to remain alive, whether awake or asleep. Of course our movement is minimal (our chest must rise and fall periodically) and although it is periodic, it never stops throughout our lifetime.
Most fishes are able to pump water into their mouths, over their gills, and out of their gill openings so are able to remain static in the water and still receive plenty of oxygen. But fishes like the tunas and sharks don’t have this muscular ability and are therefore obligated to swim continuously to bathe their gills with oxygen-rich water. Guess you could picture yourself having to run at some speed to force air into your lungs – that would be very tiring!
One of the most interesting features about the tunas is the fact that although we think of fish as ectotherms (cold-blooded or the same temp as their environment) tunas are able to maintain a body temperature that is above the surrounding water – definitely not a typical fish! It’s believed that the higher body temperature allows these fish to digest and utilize their food more quickly as well as attain sudden bursts of activity that would otherwise not be possible. Tunas are certainly impressive fish.
Activities
Science – Look Inside
Objectives: General overview of fish anatomy
Materials: Materials: Access to internet
Many students are unable to perform actual dissections in the classroom so I’ve found a very basic fish dissection that you can view. You can take a look at the general anatomy of a fish in this online material – make sure you look at the gills.
Online Dissection
Check out www.amonline.net.au
Be sure also to check out the interesting tuna tagging website we’ve shared on tagging tuna for research. You’ll notice that they’ve placed a hose in the tuna’s mouth so they can keep a constant flow of water/oxygen to the fish.
Key Concepts
Structures and Functions, Behavior and Regulation
Questions
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