Next Content
Previous Content
Chapter 0: Instructor's Guide to Integrating Concepts in Biology

What are the five Big Ideas of Biology? How are they connected to each other and the five Levels of Biology?

ICB helps your students learn biology the same way that practicing biologists carry out research and look for connections between key concepts. With the explosion of new discoveries in biology, a focus on major concepts is more beneficial than memorization of growing lists of facts.3,8,16 The structure of ICB is built on five Big Ideas of Biology in which all biological concepts are embedded (Figure 2). The five Big Ideas presented in this textbook are:

Figure 2. The five Big Ideas of biology, with the five size scales embedded in each Big Idea.

1. Living systems have multiple mechanisms to store, retrieve, and transmit information.

2. The diversity and unity of life can be explained by the process of evolution.

3. Cells are a fundamental structural and functional unit of life.

4. Interdependent relationships characterize biological systems, and these interactions give rise to emergent properties.

5. Biological systems maintain homeostasis.


Each Big Idea is examined at five size scales of life. The five size scales considered in this text, from smallest to largest, are:

  • Molecular
  • Cellular
  • Organismal
  • Population
  • Ecological system

An ecological system, also known as an ecosystem, is a biological system composed of communities of organisms, which are composed of populations, which are composed of individuals. Individuals are composed of cells that perform functions determined by the molecular composition. ICB contains 30 chapters. Chapters 1–15 explore all five Big Ideas at molecular, cellular, and within-organismal scales. Chapters 16–30 explore all five Big Ideas in organismal, population, and ecological system scales. In each chapter, students are reminded of connections to other chapters so that they can see the continuity of life across all size scales.

In ICB, the key concepts of biology do not exist in isolation from each other; rather, they interact with each other at all scales of life. For instance, individual animals maintain and regulate homeostasis in response to information received from interactions with their environment. The mechanisms for maintenance are often at the cellular and molecular levels. The ability to maintain a particular condition or composition can be altered by evolutionary processes, and the interactions can lead to emergent properties. Biologists know that the five Big Ideas overlap with each other across all size scales. ICB connects many concepts as they pertain to different Big Ideas and size scales. For example, students will explore information at the molecular level of DNA in Chapter 1, but soon realize that information is a key component of life at every size level as they read Chapters 2 and 3 and then Chapters 16–18.


Publishing Information
Citation: Paradise, C. (2015). What are the five Big Ideas of Biology? How are they connected to each other and the five Levels of Biology?. Retrieved from