question about fish science?

Question

Not all adults feed at a high trophic level. Whale sharks (50 ft) are the largest fish and feed on plankton and small fish, while Great White sharks (20 ft) are the largest carnivorous fish and feed on sea lions, seals and large fish. Blue whales (100 ft) are the largest whale and feed primarily on plankton and krill, while the Sperm whale (45 ft) is the largest carnivorous whale feeding on fish and very large squid.
(a) How does the location of each animal's position in relation to the producers contribute to their size? Be sure to look at the food chain and the amount of energy that is being transferred between the levels.
(b) Why do you suppose the plankton feeders are able to attain such large sizes compared to the carnivores?

Answer 1

Consider the rule of 10--for each level up on the trophic scale, only about 10% of the energy is available for the next consumer. Therefore, if the amount of energy available from primary producers (plants and/or algae) is 100, the amount usable for primary consumers (herbivores) is 10, the amount available for secondary consumers (carnivores) is 1, and tertiary consumers .1. Therefore, there is a lot more available energy at the herbivore level, therefore they are accessing a greater amount of available energy.

Answer 2

We did this same project when I was in High School. I had a Betta Fish and a Peace Lilly sealed airtight in the 2 liter bottle and it survived all school year. Only time the teacher ever had anything survive. Took it home at the end of the year after 8 months in the bottle, and put it in a bigger vase with the Peace Lilly and it lived another 3-4 years before dying.

Answer 3

Animals high on the food chain have to catch their prey, which may be only a little bit smaller than they are. They have to run or swim faster their prey. So they can not grow too big. Animals that feed on much smaller animals or are vegetarians often grow much bigger, because food is easy to get and in large quantities.