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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 origin of viruses remains mysterious because of their diverse and patchy molecular and functional makeup. Although numerous hypotheses have attempted to explain viral origins, none is backed by substantive data. We take full advantage of the wealth of available protein structural and functional data to explore the evolution of the proteomic makeup of thousands of cells and viruses. Despite the extremely reduced nature of viral proteomes, we established an ancient origin of the "viral supergroup" and the existence of widespread episodes of horizontal transfer of genetic information. Viruses harboring different replicon types and infecting distantly related hosts shared many metabolic and informational protein structural domains of ancient origin that were also widespread in cellular proteomes. Phylogenomic analysis uncovered a universal tree of life and revealed that modern viruses reduced from multiple ancient cells that harbored segmented RNA genomes and coexisted with the ancestors of modern cells. The model for the origin and evolution of viruses and cells is backed by strong genomic and structural evidence and can be reconciled with existing models of viral evolution if one considers viruses to have originated from ancient cells and not from modern counterparts.

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.

A common misconception is that Darwin suggested that something as complex as the eye could not have evolved through natural selection. While the misunderstanding often comes from an incomplete reading of his argument, we have long known that intermediate varieties of eyes (e.g., eyespots, cupped eyes, and complex camera-type eyes) exist in a variety of organisms. Eyes are so common that it was thought that they had evolved independently 40-60 times. More recent molecular work, however, has identified the role of Pax6 genes and their homologs in the formation of eyes during development. The basic information for eye formation appears to have been present in the common ancestor to all bilaterans, and perhaps may be more ancient than that. This interrupted case study examines the history of evidence for eye evolution from Darwin's initial postulates, through evidence of multiple intermediate forms, concluding in an examination of Pax6 homologs. The case is primarily for an introductory biology class but an additional section would be appropriate for upper-level evolution or developmental biology courses.

Webquest activity for evidence of evolution

This case study focuses on the relationship between evolution and plasticity using a hands-on, inquiry-based approach. Students view examples from the literature that illustrate the difference between nature and nurture, or the relative contributions of genes and the environment in shaping phenotypes. Using the Trinidadian guppy system as an example, students learn about seminal work in the field in addition to exploring quantitative genetic techniques used to partition phenotypic variance between genes (G) and the environment (E). They use real data from one of the publications cited in the case to graph reaction norms illustrating GxE interactions at the family and population level. The inquiry-based approach means that students are introduced to new concepts in a stepwise fashion, and asked to develop and build their understanding using causal, explanatory evidence. The case concludes with an exercise in which students apply their knowledge to a real conservation problem in Trinidad and Tobago, where guppies are native. This case would be appropriate for an upper level biology, genetics, or evolution course.

DNA to Darwin allows 16-19 year-old school students to explore the molecular evidence for evolution through practical bioinformatics activities that use data analysis tools and molecular data. Each of the activities on this web site centres around an engaging story from recent research in molecular genetics encompassing microbiology, plant and animal biology and human evolution.

In this activity, students learn why evolution is at the heart of a world health threat. They will investigate the increasing problem of antibiotic resistance in such menacing diseases as tuberculosis and influenza. Students take on the role of staff at a public health agency who are trying to communicate the widespread problem of evolving disease-causing agents to the public.

One of my favorite "proofs" of evolution is the recurrent laryngeal nerve (RLN)-the nerve that innervates the larynx from the brain, helping us speak and swallow. It takes a very circuitous course, looping from the brainstem down around the aorta and then back up to the larynx. Here's its course in humans:

The life science/biology course is divided into 12 instructional segments grouped into four sections. In the first section, From Molecules to Organisms: Structures and Processes, students develop models of how molecules combine to build cells and organisms (IS1 [Structure and Function]; IS2 [Growth and Development of Organisms]; IS3 [Organization for Matter and Energy Flow in Organisms]). In the second section, Ecosystems: Interactions, Energy, and Dynamics, students zoom out to the macroscopic scale to show how organisms interact (IS4 [Interdependent Relationships in Ecosystems]; IS5 [Cycles of Matter and Energy Transfer in Ecosystems]; IS6 [Ecosystem Dynamics, Functioning, and Resilience]; IS7 [Social Interactions and Group Behavior]). Students return to the role that DNA plays in inheritance during the third section, Heredity: Inheritance and Variation of Traits (IS8 [Inheritance of Traits]; IS9 [Variation of Traits]). The class ends tying together interactions at all these scales by explaining evolution and natural selection in Biological Evolution: Unity and Diversity (IS10 [Evidence of Common Ancestry and Diversity]; IS11 [Natural Selection]; IS12 [Adaptation and Biodiversity]). A vignette in IS12 illustrates the level of three-dimensional understanding students are expected to exhibit as a capstone of the course.

1 page summaries of different lines of evidence for evolution from Nature

This case study introduces students to the "Red Queen Hypothesis." The hypothesis states that when two species compete for a limited resource or exist in a predator-prey relationship, in order for the antagonists to remain in relative population equilibrium, there must be ongoing and reciprocal adaptation on each side. If one species fails to adapt, it may quickly face extinction. Students are introduced to the Red Queen Hypothesis through an excerpt from Lewis Carroll's novel, Through the Looking Glass, in which Alice meets the Red Queen. They then review experiments from the research literature to evaluate the validity of the hypothesis in extant populations.  Students culminate their learning by contrasting their knowledge of the Red Queen Hypothesis to Darwinian evolutionary theory based on a passage from On the Origin of Species.  Students then craft a letter to Darwin helping to explain his "wedge" theory, a notion he originally developed but removed from later iterations of his book due to a lack of experimental evidence. Originally developed for advanced high school biology students, the case also may be used in a college-level introductory course on evolutionary biology.

Muscogee County School podcasts:  math, science, language arts, science videos

Middle and high school students need an opportunity to construct evidence-based explanations for how variation and natural selection can lead to adaptation of populations over time (NGSS MS-LS4-4 and HS-LS4-4). However, managing a population of classroom-friendly living organisms that consistently grow, develop, and thrive while students observe variation among individuals can be a real challenge.