< BackNext >PreviewMain Chapter 2 It's Alive!! Or Is It? Preview Section 1 Characteristics of Living ThingsCharacteristics of Living Things Section 2 The Necessities of LifeThe Necessities of Life Concept Map

< BackNext >PreviewMain Section 1 Characteristics of Living Things Chapter 2 Bellringer Pull out a blank piece of paper and brainstorm characteristics of living things. What does it mean to be alive.

< BackNext >PreviewMain Chapter 2 What You Will Learn Living things are composed of one or more cells. Living things sense and respond to changes in their environment. Living things produce offspring through sexual reproduction or asexual reproduction. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Chapter 2 What You Will Learn, continued The cells of living things contain DNA. Living things use energy. Living things grow and develop. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Chapter 2 1. Living Things Have Cells All living things have six characteristics in common. One characteristic is the presence of cells. A cell is the structural and functional unit of life. A cell is the smallest unit that can carry out the activities of life. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Chapter 2 Living Things Have Cells, continued In single-celled organisms, different parts of the cell perform different functions. In organisms with many cells, different kinds of cells perform specialized functions. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Chapter 2 2. Living Things Sense and Respond to Change A change that affects the activity of an organism is called a stimulus (plural, stimuli). –Ex. When you touch a hot stove your body reacts to the stimuli Examples of stimuli include chemicals, gravity, light, sound, and hunger. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Chapter 2 Living Things Sense and Respond to Change, continued While conditions may change in the surrounding environment, an organism must maintain a constant internal environment to survive. This is called homeostasis. Different types of organisms achieve homeostasis in different ways. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Chapter 2 3. Living Things Reproduce A third characteristic shared by living things is the ability to produce offspring like themselves. In sexual reproduction, two parents produce offspring that share characteristics of both parents. In asexual reproduction, a single parent produces offspring that are identical to the parent. Most single- celled organisms, and some multi-celled organisms, reproduce asexually. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Section 1 Characteristics of Living Things Chapter 2

< BackNext >PreviewMain Chapter 2 4. Living Things Have DNA A fourth characteristic shared by all living things is the presence of deoxyribonucleic acid, or DNA, within the cells. When organisms reproduce, they pass on copies of their DNA to their offspring. This ensures the passing of traits to the offspring. The passing of traits is called heredity. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Chapter 2 5. Living Things Use Energy A fifth characteristic shared by living things is the use of energy to carry out the chemical activities of life. These chemical activities include growing, building cells, and moving materials in and out of cells. The sum of all the activities that an organism performs is called its metabolism. Section 1 Characteristics of Living Things

< BackNext >PreviewMain Chapter 2 6. Living Things Grow and Develop The sixth and final characteristic shared by all living things is the ability to grow. As living things grow, they may also develop and change. Many organisms grow only during certain stages of their lives. Section 1 Characteristics of Living Things