Figuring Out Sharks

Lesson at a glance:
Students use mathematical skills and problem solving to compare the size of a white shark and a basking shark and to compare each shark’s nutritional requirements to the students own.

Oregon Common Curriculum Goals and Benchmarks:
Statistics and Probability
     Common Curriculum Goal: Analyze data to determine the strength of relationships
      between sets, draw conclusions and make predictions.
     Grade 5 Benchmark: Formulate and solve problems that involve collecting and
      analyzing data.

Materials:

  • Copies of the math problems

  • A bathroom scale

  • A measuring tape attached to the wall

  • Pencils

  • Calculators

  • Scratch paper

  • Clipboards

Background information:
Sharks range in size from the pygmy shark, which measures only about six inches in length, to the whale shark, which reaches fifty feet. In addition to the wide variety of sizes, sharks also have very diverse feeding habits. Many sharks are hunters, pursuing fast moving prey such as tuna, sea lions and even other sharks. There are a few shark species; however, that are filter feeders, with plankton, krill and small fishes making up the majority of their diet.

Two very important factors come together to create an efficient ocean predator—size and speed. White sharks and mako sharks are perfect examples of this combination, hunting larger prey items including sea lions, dolphins, swordfish and turtles. White sharks hunt the largest prey, often specializing in marine mammals. Using finely tuned senses combined with great strength and speed, white sharks ambush their prey. After feeding, these sharks may go without food for several days up to a few weeks before hunting again.

Some of the largest sharks eat the smallest prey. Whale sharks and basking sharks are filter feeders that strain plankton and krill through their gill rakers. Gill rakers are elongated skeletal projections that strain food particles from the water. Whale sharks often suck in schools of small fish, which are feeding on the plankton, while basking sharks are ram-type filter feeders. Ram-type filter feeders swim slowly through the water with their mouths open. Basking sharks can filter 500,000 gallons of water in one hour.

Refer to “Sharks, Rays and their Relatives” for more background on sharks.

Activity:  Assign the attached worksheet.

Extensions:

  1. Have your students compare their heights to the lengths of one or more species of shark.

  2. Have your students compare their weights to the weights of various species of shark.

  3. Have your students graph the length and weight of each shark species.

  4. Have your students compare the amount of food eaten by white sharks and basking sharks with a bar graph.

  5. Have your students investigate how basking sharks feed versus how whale sharks feed.

  6. Have your students investigate how white sharks feed versus how hammerhead sharks feed.