Evolution 17: Evolution and Us
Students develop a Google Slideshow to help scientists convince the public that learning about and understanding evolution is directly relevant to people’s lives. They shared these presentations within the classroom. Check out some of the presentations below!
Evolution 16: Manipulating Genes
Students search a collection of websites for information about one or more technologies that people have developed to affect traits of organisms. They summarize the key points from at least two sources and synthesize the information. They evaluate each source according to a set of criteria. Students share the results of their research with their peers. Finally, students consider the possible trade-offs of using these technologies.
Links about selective breeding and artificial selection
Links about genetic modification and genetic engineering
Evolution 15: Bacteria and Bugs: Evolution of Resistance
Students obtain information about four types of organisms that have evolved resistance to chemical control methods. Students identify the cause-and-effect relationship between human activity and the evolution of resistance to chemical controls, and they consider whether this pattern is likely to continue in the future. They conclude by using the principles of natural selection to explain the phenomenon of the evolution of antibiotic resistance.
Evolution 14: The Sixth Mass Extinction?
Students examine a graph showing rates of extinction over time and identify episodes where rates of extinction were well above the background rate of extinction. They match information on cards about the five major extinction events identified by scientists to the graph. They also summarize the possible causes for these extinctions. Students then read about rates of extinction since 1500 and examine possible causes for those extinctions. Students consider whether there is currently a sixth mass extinction due to humans and, if so, whether people should do anything to prevent it.
Learn more about how humans might be affected by extinction of species and loss of biodiversity.
Read about the growing scientific interest in bioprospecting and extremophiles in Yellowstone National Park.
Read about how scientists are bioprospecting for novel antibiotic drugs with the leafcutter ant.
Your Inner Fish
How did your body become the complicated, quirky, amazing machine it is today? Anatomist Neil Shubin uncovers the answers in this new look at human evolution. Using fossils, embryos and genes, he reveals how our bodies are the legacy of ancient fish, reptiles and primates — the ancestors you never knew were in your family tree.
Evolution 13: Embryology
Students first examine forelimb skeletons of six species to identify bones with homologous structures and functions. Although the fully formed limbs appear different on the outside, students are able to identify similarities at the skeletal level. Students then examine embryological development of limbs and notice many similarities between different species. Finally. students examine the development of whole embryos of different species to infer evolutionary relationships.
Sully and Sadie color code homologous structures in assorted vertebrate forelimbs.
PBS Evolution: Great Transformations
What underlies the incredible diversity of life on Earth? How have complex life forms evolved? The journey from water to land, the return of land mammals to the sea, and the emergence of humans all suggest that creatures past and present are members of a single tree of life.
Evolution 12: A Whale of a Tale
Students investigate how fossil history provides another line of evidence for evolution. They compare the skeleton of a living whale to fossils of its extinct ancestors and use anatomical differences to arrange the skeletons in order. Students apply the theory of natural selection to whale evolution, using anatomical adaptations to infer the habitats and lifestyles of extinct species. Below are some additional links with more information about the evolution of whales:
Read about a study that revealed genetic evidence of how whales evolved from land mammals.
View a drawing and diagram on the evolution of cetaceans (whales, dolphins, and porpoises).
Scroll down this site to find information and photos on whale evolution and to link to related sites. Site maintained by University of California Museum of Paleontology.
View an artist’s drawing of Ambulocetus from the British Broadcasting Company. Read the physical description, habitat, diet and behavior of this "walking whale that swims."
Evolution 11: Family Histories
Students draw and compare double bar graphs showing changes in the numbers of fossil families in the fish, reptile, and mammal classes over geologic time. From this evidence, they can conclude that both speciation and extinction have occurred in all classes of vertebrates for as long as each class has existed. Students discuss how this evidence provides further support for a branching model for evolution.
Evolution 10: Fossil Footprints
Students interpret fossilized footprint evidence that is presented to them in stages. Through this process, they develop their skills at distinguishing observations from inferences, and at modifying hypotheses in light of new evidence. They also learn about other kinds of evidence that can be gathered from fossils, such as behavior. The fossil footprint model is based on real dinosaur tracks from Dinosaur Ridge, outside Morrison, Colorado.
PBS Evolution: Extinction
Five mass extinctions have occurred since life began on Earth. Are humans causing the next mass extinction? And what does evolutionary theory predict for the world we will leave to our descendants?
Evolution 9: Fossil Evidence
Students examine and describe four types of fossils from various localities and geologic time periods. Students then examine four simulated drill cores, representing a fictional series of rock layers found in different parts of the world. The fossils in the drill cores are the same four fossils they examined. Based on the fossils contained within the layers, students are asked to determine how the layers in each locality correlate to the layers from the other localities. They are then challenged to use this fossil evidence to construct a timeline showing the relative time spans of each species represented by the actual fossils.
Evolution 8: History and Diversity of Life
Students read text and examine graphs and charts to obtain information about both a brief history of life on Earth and a glimpse at the diversity of life on Earth today, as well as in the past. Stop to Think questions guide them through the Reading to develop an understanding of the dynamic nature of life on Earth.
Evolution 7: Origins of Species
Students explore and explain how one species of finch arriving on the Galapagos Islands 3 million years ago evolved into the current 13 species. They also explore how recent changes in the environment have selected for different beak shapes and sizes within a species, reinforcing cause-and-effect relationships. Students learn that evidence from the Galapagos finches supports scientists’ assumptions that the same processes that operated in the past are operating today; thus, the same cause-and-effect relationships happening in Galapagos finches today also happened in the past.
- There is variation among birds in a population, and this variation is passed from parents to offspring.
- In some environments, natural selection favors one beak shape; in others, a different shape is favored.
- This change, or evolution, can happen over a very short period of time.
- When it happens over a long period of time and the changes involve mating behaviors, the populations may become separate species.
- The mating behavior maintains the separation.
PBS Evolution: The Evolutionary Arms Race
Survival of the fittest: Raw competition? Intense cooperation? Both are essential. Interactions between and within species are among the most powerful evolutionary forces on Earth, and understanding them may be a key to our own survival.
Evolution 6: Mutations and Evolution
Students use a computer simulation to extend their investigation around the inheritance of the hemoglobin mutation. The simulation first extends their data from the previous activity through 30 generations. Then students are able to adjust the environmental conditions to see how access to resources and the prevalence of malaria influence the distribution of the hemoglobin gene over time.
Evolution 5: Mutations: Good or Bad?
Students follow the inheritance of a hemoglobin mutation through two generations. Students identify patterns in their data and investigate the cause-and-effect relationship between environmental conditions and the frequency of a trait in a population. Based on their data collection and analysis, students construct explanations for how changes to a gene influence an organism’s ability to survive and reproduce. Specifically, students use the example of hemoglobin to explain how structural changes to genes (i.e., mutations), lead to changes in protein structure and function, and how this can lead to changes in the function of red blood cells which, in turn, can affect survival of individuals with the mutation.
PBS Evolution: Darwin's Dangerous Idea
Why does Charles Darwin's "dangerous idea" matter more today than ever, and how does it explain the past and predict the future of life on Earth? This episode of the PBS series Evolution, interweaves the drama of Darwin's life with current documentary sequences, introducing key concepts of evolution.
Evolution 4: Battling Beaks
In this entertaining activity, the students simulated the effect of natural selection on an imaginary forkbird species. Genetic mutations, represented by tosses of a number cube, introduced variation into the population. They discover that mutations provide the variation on which natural selection acts. Some mutations cause traits that have the effect of enhancing an organism’s survival in its current environment. Students explain that individuals possessing these adaptive traits survive to have relatively more offspring. Thus, these traits become proportionally more common in the next generation. At the close of the activity,the class discussed the role of variation in the process of natural selection.
Evolution 3: A Meeting of Minds
In this activity, the students role-played an imaginary meeting between Charles Darwin, Jean-Baptiste Lamarck, a modern-day science reporter, and a middle school student. In the role play, Darwin and Lamarck engage in scientific argument as they present and compare their explanations for how a change in a species occurs. Students learn that Darwin’s explanation has been accepted as the Theory of Natural Selection and that this theory is essential to our understanding of evolution.The students learned that natural selection can be summarized as follows:
1. Variation within a species occurs naturally. (We now know this is due to genetic mutations occurring during chromosome replication.)
2. Organisms must compete for limited resources to survive.
3. The individuals that are better fit for current environmental conditions (due to their traits, which we now know are encoded at least in part in their genes) survive and reproduce more often than the others do (“survival of the fittest”).
4. As a result, the genes and traits that are most common in a population can change through time.
Evolution 2: Hiding in the Background
Using toothpicks of two colors, students simulate the effect of prey coloration on predation rates by birds. They calculate and graph the changing frequencies of worm colors over successive generations. Students consider how this model is similar to the antibiotic scenario in the previous activity.
Evolution 1: The Full Course
In this activity, the students model the effects of antibiotics on a population of disease-causing bacteria during an infection. Students toss number cubes to determine whether an infected individual remembers to take the prescribed daily dose of antibiotics, which in turn affects the size and antibiotic resistance of the bacterial population in the patient. Students keep track of and graph the population size of the remaining bacteria depending on their resistance to antibiotics. Students consider the effect of changing the chemical environment on the survival of bacteria with varying levels of antibiotic resistance. (Also, our baby chicks arrived today!!)