Introduction to Phylogenies and the History of Life

Read and analyze a phylogenetic tree that documents evolutionary relationships

This bee and Echinacea flower (Figure 1) could not look more different, yet they are related, as are all living organisms on Earth. By following pathways of similarities and changes—both visible and genetic—scientists seek to map the evolutionary past of how life developed from single-celled organisms to the tremendous collection of creatures that have germinated, crawled, floated, swam, flown, and walked on this planet.

 Photo shows a bee collecting nectar from a flower.

Figure 1. The life of a bee is very different from the life of a flower, but the two organisms are related. Both are members the domain Eukarya and have cells containing many similar organelles, genes, and proteins. (credit: modification of work by John Beetham)

What You’ll Learn to Do

  • Discuss the components and purpose of a phylogenetic tree
  • List the different levels of the taxonomic classification system
  • Compare homologous and analogous traits
  • Discuss the purpose of cladistics
  • Identify different perspectives and criticisms of the phylogenetic tree

Learning Activities

The learning activities for this section include the following:

  • Phylogenetic Trees
  • Taxonomy
  • Homologous and Analogous Traits
  • Cladistics
  • Perspectives on the Phylogenetic Tree
  • Self Check: Phylogenies and the History of Life