Lecture Outline
Overview: Inquiring About Life
• Organisms are adapted to the environments they live in.
• These adaptations are the result of evolution, the fundamental organizing principle of biology and the core theme of this book.
• Posing questions about the living world and seeking science-based answers are the central activities of biology, the scientific study of life.
• Biologists ask a wide variety of ambitious questions.
○ They may ask how a single cell becomes a tree or a dog, how the human mind works, or how the living things in a forest interact.
• Biologists can help answer questions that affect our lives in practical ways.
• What is life?
○ The phenomenon of life defies a simple, one-sentence definition.
○ We recognize life by what living things do.
Concept 1.1 The themes of this book make connections across different areas of biology.
• Eight unifying themes will help you organize and make sense of biological information.
Theme 1: New properties emerge at each level in the biological hierarchy.
• Each level of biological organization has emergent properties.
• Biological organization is based on a hierarchy of structural levels, each building on the levels below.
○ At the lowest level are atoms that are ordered into complex biological molecules.
○ Biological molecules are organized into structures called organelles, the components of cells.
○ Cells are the fundamental unit of structure and function of living things.
• Some organisms consist of a single cell; others are multicellular aggregates of specialized cells.
• Whether multicellular or unicellular, all organisms must accomplish the same functions: uptake and processing of nutrients, excretion of wastes, response to environmental stimuli, and reproduction.
• Multicellular organisms exhibit three major structural levels above the cell: Similar cells are grouped into tissues, several tissues coordinate to form