BIO101 Study Guide

Unit 1: Introduction to Biology

1a. List the basic characteristics of life that are common to all living things

  • How is a nonliving thing (such as a rock) different from a living organism (such as a mouse)?
  • Can you point to examples of nonliving things that have some characteristics of life?
  • How is a dead organism different from a living organism?

Biology is the study of living things, which are also known as organisms. To determine what makes something alive, we must consider characteristics that are common to organisms. Chemistry is the study of non-living matter.

Though there are many different kinds of organisms, all organisms share these characteristics:

  • Response to the environment

  • Growth and developmental change

  • Reproduction

  • Energy processing and chemical metabolism

  • Regulation and maintenance of homeostasis

  • Orderly structure with cellular basis

  • Evolutionary adaptation based on the transmission of heritable traits

Some nonliving things have some of these characteristics, but to be alive, something must have all of the characteristics. For example, a crystal has a high degree of order and can grow, but it does not maintain homeostasis.

Review this material in Advanced Characteristics of Life and Introduction to Biological Systems.


1b. List the levels of organization of life and characteristics of each level

  • What makes each level different from the one below it (or the level above it)?

The levels of organization in biology are characterized by increasing complexity and order. They are structured in a hierarchical (or nested) arrangement. For example, atoms of different types form more complex structures called molecules. Molecules can form more complex structures called organelles, and so on. You should be able to list the levels of organization – from atoms all the way up to the biosphere.

  • Atom - basic building block of matter

  • Molecule - multiple atoms bonded together

  • Organelle - subcellular structure with specific functions

  • Cell - basic unit of life

  • Tissue - collection of cells

  • Organ - multiple tissues packaged for a particular function

  • Organ System - group of functionally related organs

  • Organism - a living individual

  • Population - group of individuals of the same species

  • Community - different populations living together

  • Ecosystem - a community along with the nonliving surroundings

  • Biosphere - includes all living things and their surroundings

Review the levels of biological organization in Introduction to Biological Systems. It addresses the biological hierarchy starting at 15:10.


1c. Describe the steps of the scientific method and the importance of using the scientific method in research

  • What is science?
  • How does science work?

Science is a logical system of inquiry. Consequently, science allows us to learn about ourselves and the universe we live in. A critically important aspect of science is that it is based on evidence and is observational. Beyond mere observation, science involves the systematic testing of hypotheses. A hypothesis is an explanation for an observation, the process of gaining information. A hypothesis (which might be correct or incorrect) is a prediction and attempts to explain why something is the way it is.

The active part of science is devising experiments to test hypotheses. A hypothesis is supported (although not proven) if an appropriate experiment yields the results the hypothesis predicted. Otherwise, you must modify or reject the hypothesis. This basic process has allowed us to learn about the universe. Biology is the corner of science that deals with living things in the universe, but biology is otherwise no different from science in general.

As you review the nature and process of science, pay particular attention to the steps in the following flowchart, which demonstrates how science is a process. You should also understand the distinction between basic and applied science.

To review this material, see The Process of Science.


Unit 1 Vocabulary

You should be familiar with these terms as you prepare for the final exam.

  • atom
  • biology
  • biosphere
  • cell
  • chemistry
  • community
  • ecosystem
  • environment
  • experiment
  • homeostasis
  • hypothesis
  • molecule
  • observation
  • organ system
  • organelle
  • organism
  • population
  • prediction
  • reproduction
  • science
  • tissue