Regulation and Behavior Behavior is one kind of response an organism can make to an internal or environmental condition. An ecosystem is composed of all populations of organisms living together and physical factors with which they interact. Populations of organisms can be categorized as producers and consumers by the function they serve in the ecosystem. These grade level performance standards are listed developmentally. However, each school is uniquely organized.
Specialized cells perform specific functions in multi-cellular organisms.
Reproduction and Heredity Inherited traits are determined by genes. Regulation and Behavior Regulation of an organism's internal environment involves sensing its environment and changing physiological activities to keep conditions within the range required to survive. Some activities practiced by humans can accelerate changes in the natural environment. The number of organisms an ecosystem can support depends on the biotic and abiotic resources available. The unity among organisms becomes apparent from an analysis of internal structures, the similarity of their chemical processes, and the evidence of common ancestry.