1. Life Functions Characteristics of Life

2. Life Functions In order to be considered a living thing, an organism needs to have certain characteristics, and perform these life activities: 1. NUTRITION: Obtaining materials from its environment and preparing it for use. a.Ingestion- The taking in of food b.Digestion- The breakdown of food for absorption. c.Egestion- The removal of indigestible or undigested food.

3. 2. TRANSPORT- Absorption of materials and distribution of materials throughout the cells * Assimilation 3. RESPIRATION- Obtaining energy from food materials in order to maintain life. *Using glucose to make ATP 4. EXCRETION- removal of waste products produced within the organism. 5. SYNTHESIS- Chemical activities that build large molecules from smaller ones.

4. 6. REGULATION- Control and coordination of various activities. 7. GROWTH- Process of using products of synthesis to increase in size. 8. REPRODUCTION- Process by which living things produce a new individual. 9. METABOLISM- ALL chemical reactions occurring within the cells so an organism can carry on its life functions. *Anabolism vs. Catabolism

5. All these activities assure that an organism is in HOMEOSTASIS: -the control and regulation the organism has to maintain a stable internal environment. (*dynamic equilibrium) Homeostasis introduced by Claude Bernard in the 19 th century.

6. SUMMARY Living things and organisms have all the following characteristics: Highly organized Made up of one or more cells Have a definite shape and limited size Have a limited life span Energy Grow Respond to environmental changes Reproduce Evolve, or change over time