Jesse_wolfstadt's Blog
Answer to Week #8 Lab Team Challenge Question
Posted By: Jesse_Wolfstadt, Dr. Hawke on Friday, December 08, 2006
Hey Polar Scientists!
I hope you have all had enough time to answer last weeks' challenge question: based on what you have learned about the feeding havits of the Weddell seal and muscle physiology in general, why do you think the Weddell seal muscle has a high percentage of Type I, slow twitch fibres? Why would these animals also have some Type IIa intermediate muscle fibres?
Weddell seals get their food by diving for long periods of time below the surface of the ice. Thus, they need to be able to maintain a high level of endurance. Type I fibres are more suited for endurance activities, so Weddell seals have a higher percentage of these fibres than Type IIb fast twitch fibres. As well, Weddell seals also have Type IIa intermediate fibres. These fibres provide a moderate amount of endurance, so they also contribute to the Weddell seals ability to keep active and dive for long periods of time. In addition, these fibres are extremely useful because they share some of the properties of fast twitch fibres, such as faster and stronger contractions.
Good work students of the Alberta Rockies on answering the challenge question.