Hhmi Lizard Evolution Lab Answers

[Vannessa Rataj]

TheCaribbean is home to about 150 species of anole lizards. In this lab, students investigate how so many species of anoles evolved. The lab includes four modules that cover different concepts in evolutionary biology, including adaptation, convergent evolution, phylogenetic analysis, reproductive isolation, and speciation. In each module, students engage in key science practices, including taking measurements to collect data, constructing and interpreting graphs, and performing statistical analyses.

Finally, as they discover biblical answers from the creation perspective, light bulbs turn on, and their perplexity is replaced with relief. They then are able to communicate their thoughts about origins more coherently and confidently.

We have the privilege and responsibility of teaching and shepherding the young ones under our care (Deuteronomy 6:7; Luke 12:42). It is a tough job, but we must prepare them well for the arduous trials of mature Christian life.

When parents hear my suggestion, they sometimes express fear that the young Christian might begin to believe the evolutionary ideas. However, going through this process in advance, under the care of a more mature Christian, is far better than to being exposed to it for the first time in a hostile environment. Which will be better to prepare soldiers: pamper them until their first battle, or toughen them by rigorous training and battle simulations?

Developing discernment is incredibly difficult. The enemy is good at cleverly intertwining truth and falsehood, so it is hard to tell the difference. Hebrews 5:14 tells us that mature Christians need to be trained, through practice, to discern between good and evil. Being able to untangle these knots is crucial.

All of this requires practice. They (not you) need to be doing the mental work. Requiring them to work out the answers is far better than spoon-feeding them. They should be the ones primarily asking questions and evaluating their own beliefs.

Students need to learn to constantly ask themselves this question every time they read about evolution: Is the author referring to observed changes in animals living in the present or a hypothesis of unobserved vast changes in the past?

Often, a perspective we have already learned will apply to many different cases. One such perspective repeatedly stands out: a single Designer provides a more satisfying explanation for similarities in living things.

Consider how creationists respond to possibly the most famous evidence for evolution, homology. This is the claim that living things are so similar that they must have come from a common ancestor. But these similarities also make sense if a single Creator made all living things. Young people quickly grasp the point if you show them multiple buildings designed by the same architect or play multiple songs written by the same composer (just listen to film scores by John Williams).

Ultimately, it is not up to us to decide who will embrace a life of faith and obedience to Christ. But God has called us to do our part to prepare a generation that will persevere and brightly share his light with the world. He wants us to be intentional in our training. That includes teaching evolution.

Christians often confuse species (a modern scientific term for closely related organisms that can interbreed) with kinds (a biblical term for different, unrelated groups). In reality, God placed a large amount of variety and adaptability within each created kind so it could diversify and fill the earth.

I teach my students to avoid these terms because they create the impression that little changes can add up over time to produce completely new kinds of living things. We observe minor variations within existing kinds (a better term), but we do not observe the evolution of completely new kinds of creatures.

Virtual Lab Student Handout Lizard Evolution Virtual Lab LIZARD EVOLUTION VIRTUAL LAB Answer the following questions as you finish each module of the virtual lab or as a final assessment after completing the entire virtual lab. Module 1: Ecomorphs 1. At the beginning of the virtual lab, you were asked to sort eight lizards into categories. What criteria did you initially use to make your groups? Did you revise your criteria later? Why? 2. An adaptation is a structure or function that is common in a population because it enhances the ability to survive and reproduce in a particular environment. Provide one example and an explanation of one adaptation in the Anolis lizards. 3. Provide one evolutionary explanation for why lizards living in the same part of the habitat (i.e., grass) would have similar characteristics. 4. What is an ecomorph? Provide one example from the virtual lab. 5. How is an ecomorph different from a species? 6. Explain how a particular body feature of one of the lizard ecomorphs from the virtual lab is an adaptation to their particular niche. www.BioInteractive.org February 2015 Page 1 of 5

Virtual Lab Student Handout Lizard Evolution Virtual Lab Module 2: Phylogeny 1. In module 1, you identified which species of lizards were most similar to one another based on relative limb length and toe pad size. In this module, you determined which lizards are more similar to one another based on what type of information? 2. Are the species of lizard that are more similar to one another according to body type also more closely related based on the results obtained in this module? Explain your answer. 3. The figures below show two phylogenetic trees similar to the one you constructed in the virtual lab but with more lizards. The trees below show the evolutionary relationships among species from four ecomorphs from the four largest Caribbean islands. www.BioInteractive.org Figure 1. Phylogeny of anole lizards on four of the major Caribbean islands color-coded according to geographical distribution. Light dotted line, Puerto Rico; small dashed line, Cuba; large dashed line, Hispaniola; and solid line, Jamaica. Figure 2. Phylogeny of anole lizards in the four major Caribbean islands colored in according to ecomorph. Light dotted line, twig; small dashed line, trunk-ground; large dashed line, trunk-crown; solid line, grass- bus. February 2015 Page 2 of 5

Virtual Lab Student Handout Lizard Evolution Virtual Lab Module 4: Dewlap Colors 1. Anolis cristatellus and A. cooki are both trunk-ground anoles that live on Puerto Rico. A. cristatellus lives in a shady, forest environment, while A. cooki lives in an open, sunny environment. What is an adaptive explanation for why the dewlap of one species evolved to be brighter and that of another species darker? 2. From the bar graph generated in the virtual lab (see below), how do the dewlap colors of the two species compare? 3. How would you determine whether the difference between the two populations is statistically significant? 4. If a species of anoles with dark dewlaps colonized a heavily forested island, predict what would happen over time to the color of the dewlap. Using your knowledge of natural selection and genetics, explain your prediction. www.BioInteractive.org February 2015 Page 4 of 5

These days I am towards the other end of the student-teacher continuum and I make a point of not teaching from a textbook. First, they are WAY too expensive for students. Second, they are out of date by the time they are published. Third, if classic works are covered (like those on anoles), the format of a textbook makes even the most exciting example remote and dull. My approach has always been to go directly to the source. And anoles offer such a rich collection of content for educators.

Previous analysis of the scapulocoracoid in isolation revealed that its shape differs between Anolis habitat specialists, and resembles a particularly dorsoventrally tall shape in twig anoles (Tinius et al. 2020). The other ecomorph groups (trunk-ground, trunk-crown, and crown-giant) show obvious tendencies towards a particular structural organization, but in none of these does the scapulocoracoid resemble a truly characteristic shape.

HHMI produced several fantastic videos and learning modules perfect for learning about anoles, ecology, and evolution in the classroom and at home! Each of the activities also comes with handy educator materials to make sure your newly homeschooled students gets the most out of these resources.

In another excellent study exploring the effects of anthropogenic activity on evolution in anoles, Postdoctoral Fellow Claire Dufour is investigating how the recent introduction of Anolis cristatellus from Puerto Rico to the island of Dominica may be driving changes in the display behavior of Anolis oculatus, a Dominica native. Specifically, Dufour is asking whether interactions between the A. cristatellus and A. oculatus are consistent with patterns of Agonistic Character Displacement, in which interference competition between the newly sympatric species results in shifts in traits affecting the rate, intensity, and outcome of interspecific aggression.

To begin, Dufour and colleagues constructed a pair of robots that mimicked the typical look and display behavior of a male A. oculatus and A. cristatellus. She then traveled across Dominica and presented over 130 wild male A. oculatus with one of the two robots, and recorded the display behavior exhibited in response. Beyond measuring the duration of the response display, Dufour also tracked the proportion of time spent by the A. oculatus engaging in any of nine specific display behaviors, such as dewlap extensions, push ups, nuchal crest presentations, and others. By repeating this experiment among populations of A. oculatus existing sympatrically with A. cristatellus, as well as populations not yet invaded by A. cristatellus, Dufour was then able to ask whether variation in display time or composition among the native anoles could be attributed to the presence of A. cristatellus. Indeed, this turned out to be the case.

Anolis oculatus living in allopatry from the introduced A. cristatellus were found to engage in longer display bouts when presented with the conspecific robot, and shorter display bouts when presented with the unfamiliar A. cristatellus robot. Alternatively, A. oculatus occupying habitats already intruded by the A. cristatellus increased the duration of time spent displaying, regardless of which robot was presented. In addition, A. oculatus were also found to alter the behavioral composition of their displays when occupying habitats shared by the introduced A. cristatellus.

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