Key Idea 5:  Organisms maintain a dynamic equilibrium that sustains life.
5.1  Compare the way a variety of living specimens carry out basic life functions and maintain dynamic equilibrium
Major Understandings	Suggested Activity
5.1a  Animals and plants have a great variety of body plans and internal structures that contribute to their ability to maintain a balanced condition.
5.1b  An organism's overall body plan and its environment determine the way that the organism carries out the life processes.
5.1c  All organisms require energy to survive.  The amount of energy needed and the method for obtaining this energy vary among cells.  Some cells use oxygen to release the  energy stored in food.
5.1d  The methods for obtaining nutrients vary among organisms.  Producers, such as green plants, use light energy to make their food.  Consumers, such as animals, take in energy-rich foods.
5.1e  Herbivores obtain energy from plants.  Carnivores obtain energy from animals.  Omnivores obtain energy from both plants and animals.  Decomposers, such as bacteria and fungi, obtain energy by consuming wastes and/or dead organisms.
5.1f  Regulation of an organism's internal environment involves sensing the internal environment and changing physiological activities to keep conditions within the range required for survival.  Regulation includes a variety of nervous and hormonal feedback systems.
5.1g  The survival of an organism depends on its ability to sense and respond to its external environment.
5.2  Describe the importance of major nutrients, vitamons, and minerals in maintaining health and promoting growth, and explain the need for a constant input of energy for living organisms.
Major Understandings	Suggested Activity
5.2a  Food provides molecules that serve as fuel and building material for all organsims.  All living things, including plants, must release energy from their food, using it to carry on their life processes.
5.2b  Foods contain a variety of substances, which include carbohydrates, fats, vitamins, proteins, minerals, and water.  Each substance is vital to the survival of the organism.
5.2c  Metabolism is the sum of all chemical reactions in an organism.  Metabolism can be influenced by hormones, exercise, diet, and aging.
5.2d  Energy in foods is measured in Calories.  The total caloric value of each type of food varies.  The number of Calories a person requires varies from person to person.
5.2e  In order to maintain a balanced state, all organisms have a minimum daily intake of each type of nutrient based on species, size, age, sex, activity, etc.  An imbalance in any of the nutrients might result in weight gain, weight loss, or a diseased state.
5.2f  Contraction of infectious disease and personal behaviors such as use of toxic substances and some dietary habits, may interfere with one's dynamic equilibrium.  During pregnancy these conditions may also affect the development of the child.  Some effects of these conditions are immediate; others may not appear for years.