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Chapter 1: “Biology and You” Section 1: “Themes of Biology” Objectives • Relate the seven properties of life to a living organism. • Describe seven themes that can help you organize what you learn about biology. • Identify the tiny structures that make up all living organisms. • Differentiate between reproduction and heredity and between metabolism and homeostasis. Characteristics of Living Organisms Biology is the study of life. All living organisms share certain general properties that separate them from nonliving things. Properties of Life » » » » » » » • • • • • • • Cellular organization Reproduction Metabolism Homeostasis Heredity Responsiveness Growth and development Cellular organization - every living thing is composed of one or more cells Reproduction - all living things are able to reproduce Metabolism - all obtain and use energy to run the processes of life Homeostasis - living organisms maintain a consistent internal environment Heredity - living things pass traits to offspring Responsiveness - all living things respond and adjust to the environment Growth and development - all living things grow and develop Unifying Themes of Biology As you study biology you will repeatedly encounter the following seven themes. Turn over your paper to see explanations of each of the following 7 unifying themes of biology. 1. 2. 3. 4. 5. 6. 7. Cellular Structure and Function Reproduction Metabolism Homeostasis Heredity Evolution Interdependence 1. Cellular Structure and Function • Cells are highly organized, tiny structures with thin coverings called membranes. All living things are made of one or more cells. A cell is the smallest unit capable of all life functions. 2. Reproduction • Reproduction is the process by which organisms make more of their own kind from one generation to the next. 3. Metabolism • Metabolism is the sum of all the chemical reactions carried out in an organism. Almost all energy used by living organisms is originally captured from sunlight. 4. Homeostasis • Homeostasis is the maintenance of a stable internal conditions in spite of changes in the external environment. An organism unable to balance its internal conditions with its environmental conditions could become ill and die. 5. Heredity • Heredity is the passing of traits from parent to offspring. The basic unit of heredity is called a gene. Genes are coded in a molecule called deoxyribonucleic acid (DNA). Genes determine an organism’s traits. A change in the DNA of a gene is called a mutation. Most mutations are harmful, but some mutations can help an organism survive. 6. Evolution • Evolution is defined as change in the inherited characteristics of species over generations. A species is a group of genetically similar organisms that can produce fertile offspring. Natural selection is the process in which organisms with favorable traits are more likely to survive and reproduce. 7. Interdependence • The organisms in a biological community live and interact with other organisms. Ecology is the branch of biology that studies the interactions of organisms with one another and with the nonliving part of their environment. Organisms are dependent on each other and on their environment.