Why discuss the history of life on Earth?

Human beings are just one of countless examples of life on Earth. The sheer amount of diversity can seem overwhelming. However, over the years, scientists have developed tools and methods to organize all known living organisms. With the phylogenetic tree and the taxonomic classification system, scientists have grouped and organized organisms by domain, kingdom, phylum, class, order, family, genus, and species.

The term kingdom is likely familiar to you, and you may even know the genus and species names of some organisms, as these names are used to create scientific names such as Canis lupus familiaris (dogs) and Felis catus (cats). But how does this type of organization matter in everyday life?

Evolutionary biologists could list many reasons why understanding phylogeny is important to everyday life in human society. For botanists, phylogeny acts as a guide to discovering new plants that can be used to benefit people. Think of all the ways humans use plants—food, medicine, and clothing are a few examples. If a plant contains a compound that is effective in treating disease, scientists might want to examine all of the relatives of that plant for other useful drugs.

Learning Outcomes

• Explain the theory of evolution
• Define species and identify how species form
• Discuss the ways populations evolve
• Read and analyze a phylogenetic tree that documents evolutionary relationships