Describe classification and organizational tools biologists use, including modern taxonomy

Figure 1. Our planet, Earth

Viewed from space, Earth offers no clues about the diversity of life forms that reside there. The first forms of life on Earth are thought to have been microorganisms that existed for billions of years in the ocean before plants and animals appeared. The mammals, birds, and flowers so familiar to us are all relatively recent, originating 130 to 200 million years ago. Humans have inhabited this planet for only the last 2.5 million years, and only in the last 200,000 years have humans started looking like we do today.

When faced with the remarkable diversity of life, how do we organize the different kinds of organisms so that we can better understand them? As new organisms are discovered every day, biologists continue to seek answers to these and other questions. In this outcome, we will discuss taxonomy, which both demonstrates the vast diversity of life and tries to organize these organisms in a way we can understand.

What You’ll Learn to Do

• Explain the “diversity of life”
• Explain the purpose of phylogenetic trees
• Explain how relationships are indicated by the binomial naming system

Learning Activities

The learning activities for this section include the following:

• The Diversity of Life
• Phylogenetic Trees
• Taxonomy
• Self Check: Taxonomy