Phylogenies and the History of Life Resources
In scientific terms, phylogeny is the evolutionary history and relationship of an organism or group of organisms. A phylogeny describes the organism's relationships, such as from which organisms it may have evolved, or to which species it is most closely related. Scientists must collect accurate information that allows them to make evolutionary connections among organisms. It is a highly dynamic field of biology because phylogenetic modeling concepts are constantly changing as new information is collected. Over the last several decades, new research has challenged scientists’ ideas about how organisms are related.
Learning Objectives (Biology I TAGs)
- List the different levels of the taxonomic classification system.
- Compare systematics, taxonomy, and phylogeny.
- Discuss a phylogenetic tree's components and purpose.
- Discuss the limitations of phylogenetic trees.
- Compare homologous and analogous traits.
- Discuss the purpose of cladistics.
- Describe maximum parsimony and why scientists use it to determine the best tree.
- Describe horizontal gene transfer and the different ways it can occur.
- Describe how mitochondria and chloroplasts are believed to have evolved.
- Describe the different hypotheses for eukaryote evolution.
- Describe the web and ring models of phylogenetic relationships.
- Describe how the web and ring models differ from the classic tree of life model.
Recommended Textbook Resources
OpenStax: Biology 2e
This chapter describes and contrasts Linnaean taxonomy and systematics. It reviews the different types of data used in cladistics and provides an introduction to the construction of cladograms. It concludes with a discussion of the importance of horizontal gene transfer in understanding the evolution of early life.
Student Assessment Activities
Stuents watch the video about how to interpret phylogenetic trees here.
Instructors then administer one or both of these quizzes. This PDF contains both the two quizzes and their answer keys.
This is a lab activity called the Caminalcule Evolution Lab. In Part 1, students classify 14 living hypothetical species based on pictures and then create a small phylogenetic tree for them. In Part 2, they create a larger tree for 58 fossils species and look for patterns such as vestigial traits and convergence. Included in this link are instructor tips for both majors and nonmajors.
Find the correct answers to the end of the chapter “Review Questions.” Note the page number on which you found the answer. Be prepared to share and explain your answers in a group setting.
Answer the end of the chapter “Critical Thinking Questions.” Note the page number on which you found the answer. Be prepared to share and explain your answers in a group setting.