Student Activity: Predators in Control

Predator–prey relationships are one of the most important biotic relationships in the sustainability of an ecosystem. Predators are the natural controls in an ecosystem, limiting the size of a prey population. Many studies have illustrated that the long-term sustainability of an ecosystem is severely affected if top predators are eliminated. Prey populations increase as a result of the loss of their natural predators and they overgraze the vegetation resulting in ecosystem collapse.

Top predators―including wolves, grizzly bears, sea otters, and alligators―are referred to as keystone species. They are crucial in maintaining and sustaining ecosystem function. For example, on the west coast of Canada the loss of sea otters, a keystone species, has led to an increase in populations of sea urchins and other shellfish which are overgrazing on the underwater kelp forests and destroying the habitat of many different organisms.

This game models the interrelated effects of predator (fox) and prey (rabbit) populations over several generations.

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Teacher Demo/Student Activity: Iron in Cereal

iron-in-cerealFood labels often contain the word ‘fortified’.  This means that one or more ingredients have been added that are not normally found in that food item.  The purpose is to increase the amount of that mineral or nutrient to serve a dietary purpose.  Table salt is fortified with iodine (to help prevent hypothyroidism, which can lead to goiter which is the abnormal enlargement of the thyroid gland), and many breakfast cereals are fortified with fibre (to improve digestion) and iron.

Iron ions (Fe3+) are essential for the formation of red blood cells.  They are central to the hemoglobin molecule, which is responsible for the transfer of oxygen gas and carbon dioxide throughout the body.  Iron ions are also found in muscle tissue and many enzymes.  Iron is often added to cereal in its elemental form (Fe) because it is more stable and has a minimal effect on flavour.

The recommended daily intake of iron depends on age and gender.  These values are listed in the Additional Resources section, and information about iron content in food can be found in the nutritional facts label on the packaging.

The purpose of this demonstration/activity is to illustrate the importance of proper labeling and identification of substances and the presence and form of iron in breakfast cereals.

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Valentine’s Candy Science – Cool Science Experiment

alentine’s Day is a perfect time to give that loved one a selection of candy… and there’s nothing more romantic on Valentine’s Day than to give that special someone candy… and teach them how to use the candy to do some really cool science. Our science of candy expert, Steve Spangler, is here to turn candy into oohs & ahhhs. Continue reading