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A phylogenetic tree, also known as a phylogeny, is a diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor. Phylogenies are useful for organizing knowledge of biological diversity, for structuring classifications, and for providing insight into events that occurred during evolution. Furthermore, because these trees show descent from a common ancestor, and because much of the strongest evidence for evolution comes in the form of common ancestry, one must understand phylogenies in order to fully appreciate the overwhelming evidence supporting the theory of evolution.

Paul Strode describes the HHMI BioInteractive Click and Learn activity on DNA sequencing and phylogenetic trees. He describes how it teaches students DNA sequence alignment, and how those sequence differences allow researchers to determine relationships between species. Visit www.biointeractive.org/phylo-tree to use the interactive resource, and to find related materials. Subscribe to the BioInteractive YouTube channel to get the latest educator tips!

The virtual lab includes four modules that investigate different concepts in evolutionary biology, including adaptation, convergent evolution, phylogenetic analysis, reproductive isolation, and speciation. Each module involves data collection, calculations, analysis and answering questions. The "Educators" tab includes lists of key concepts and learning objectives and detailed suggestions for incorporating the lab in your instruction.

This Click and Learn explains how DNA sequences can be used to generate such trees, and how to interpret them.

The article "The difference makers" (10.9 readability score) gives an overview of transposons, or "jumping genes," and how these bits of genetic material have affected genetic variety and evolution in humans and other organisms. Students can focus on details reported in the article, follow connections to earlier articles about transposons and human evolution, explore crosscurricular connections to other major science topics, and construct a phylogenetic tree of primate evolution based on the locations of retroviral sequence insertions in chromosome 21

2 minute animation (images with text) describing how phylogenetics was used to identify likely placental mammal ancestor.

Evolutionary biologists have developed many techniques to analyze how male and female mating preferences have co-evolved. These studies combine animal behavior, sensory biology, phylogenetics, and neurobiology to observe the effects of male trait biases based on female receiver systems; that is, the "attractiveness" of the male trait to potential female mating partners.

Biologists estimate that there are about 5 to 100 million species of organisms living on Earth today. Evidence from morphological, biochemical, and gene sequence data suggests that all organisms on Earth are genetically related, and the genealogical relationships of living things can be represented by a vast evolutionary tree, the Tree of Life. The Tree of Life then represents the phylogeny of organisms, i. e., the history of organismal lineages as they change through time. It implies that different species arise from previous forms via descent, and that all organisms, from the smallest microbe to the largest plants and vertebrates, are connected by the passage of genes along the branches of the phylogenetic tree that links all of Life (Figure 1).

tutorial video with pre and post test questions on evolution

Five distinct humpback whale populations have been identified across the North Pacific Ocean in the most comprehensive genetic study of the mammals in this region yet, a new study reports.

Anthracobunidae is an Eocene family of large mammals from south Asia that is commonly considered to be part of the radiation that gave rise to elephants (proboscideans) and sea cows (sirenians). We describe a new collection of anthracobunid fossils from Middle Eocene rocks of Indo-Pakistan that more than doubles the number of known anthracobunid fossils and challenges their putative relationships, instead implying that they are stem perissodactyls.

curricular unit on Genetic Research

Scientists discovered a new retrovirus "fossil" found in the common vampire bat which is homologous to retroviruses in rodents and primates. The results suggest the recent circulation of an active infectious retrovirus and cross-species transmission. The study has been published in the scientific journal Journal of Virology.

The Tree of Life Web Project (ToL) is a collaborative effort of biologists and nature enthusiasts from around the world. On more than 10,000 World Wide Web pages, the project provides information about biodiversity, the characteristics of different groups of organisms, and their evolutionary history (phylogeny).

Taxonomy groups species by common traits. Modern taxonomy emphasizes evolutionary relatedness. Explore some principles of taxonomy by sorting twenty shells by their morphological characteristics. Whenever a pictorial index of shells appears, you can click on an image of a shell to open it in a separate window. There you can click and drag your mouse over the shell to rotate it for a more detailed examination. Additionally, you can use the small buttons in the lower right corner of the window to rotate the shell.

The seashell phylogeny and evolution activity is an interactive online activity that can be done in class or assigned as homework. The Teacher's Guide describes supporting resources that can be used to teach students about seashells and a pre-activity exercise that uses the downloadable picture cards to familiarize students with the concept of sorting organisms.

animation with associated quiz

For years whale evolution was characterized by speculation and limited evidence. Evolution critics even focused on whales as a means to criticize evolutionary theory. Now whale evolution represents one of the best examples of "macroevolution." This "clicker case" uses this fascinating story of historical irony as a backdrop to the study of whale evolution. First, students study an array of whale fossils to learn how evolution is properly viewed as a branching, relationship-based process, not a linear, progressive, "chain-of-being." Using this view they learn how scientists seek to reconstruct past relationships and study transitional features, not search for "missing links." Students then learn that evidence for macroevolution relies on several lines of independent evidence from fossils, comparative anatomy, embryology, genetics, and paleoecology. With a focus on macroevolution, this case makes a critical contribution to evolution education. It could work well in a lower level undergraduate biology / evolution / paleontology course (non-majors or majors), or in an upper-level evolution course, perhaps early in the semester as a primer for related topics.

The dewlaps of Anolis lizards provide a classic example of a complex signaling system whose function and evolution is poorly understood. Dewlaps are flaps of skin beneath the chin that are extended and combined with head and body movements for visual signals and displays. They exhibit extensive morphological variation and are one of two cladistic features uniting anoles, yet little is known regarding their function and evolution.