Students learn how DNA fingerprinting has been used in criminal investigations and discuss the limitations of and problems with DNA testing.
Students perform DNA forensics using food coloring to enhance their understanding of DNA fingerprinting, restriction enzymes, genotyping and DNA gel electrophoresis. They place small drops of different food coloring ("water-based paint") on strips of filter paper and then place one paper strip end in water. As water travels along the paper strips, students observe the pigments that compose the paint decompose into their color components. This is an example of the chromatography concept applied to DNA forensics, with the pigments in the paint that define the color being analogous to DNA fragments of different lengths.
Introduction to DNA sequencing.
As a class, students work through an example showing how DNA provides the "recipe" for making our body proteins. They see how the pattern of nucleotide bases (adenine, thymine, guanine, cytosine) forms the double helix ladder shape of DNA, and serves as the code for the steps required to make genes. They also learn some ways that engineers and scientists are applying their understanding of DNA in our world.
Overview of DNA and chromatin regulation.
Introduction to DNA cloning.
How DNA is copied (replication). How information in DNA can be used to make a protein.
This online interactive module of 10 pages or frames integrates textual information, 3D molecular models, interactive molecular simulations, and embedded assessment items to guide students in understanding the copying of DNA base sequences from translation to transcription into proteins within each cell. The module divides the exercises in to Day 1 and Day 2 time frames. Teachers can view student assessment responses by assigning the module within a class created within the Molecular Workbench application. This Java-based module must be downloaded to each computer.
Students learn how the process of soil solarization is used to pasteurize agricultural fields before planting crops. Soil solarization is a pest control technique in agriculture that uses the sun’s radiation to heat the soil and eliminate unwanted pests that could harm the crops. The approach is compared to other pest control methods such as fumigation and herbicide application, highlighting the respective benefits and drawbacks. In preparation for the associated hands-on activity on soil biosolarization, students learn how changing the variables involved in the solarizing process (such as the tarp material, soil water content and addition of organic matter) impacts the technique’s effectiveness. A PowerPoint® presentation and pre/post-quiz is provided.
This video segment from Evolution: "Darwin's Dangerous Idea," together with interviews with Daniel Dennett and James Moore, depicts Darwin struggling with publicizing his revolutionary theory.
Example questions analyzing data to justify claims in experiments.
In this video segment adapted from NOVA, scientists search for carbonized remains of plants preserved in lava flows to find out how long it has taken rain forests on Hawaii to regenerate after a volcanic eruption.
This three-act film tells the story of the detective work that solved the mystery of what caused the disappearance of the dinosaurs at the end of the Cretaceous period. Shot on location in Italy, Spain, Texas, Colorado, and North Dakota, the film traces the uncovering of key clues that led to the discovery that an asteroid struck the Earth 66 million years ago, triggering a mass extinction of animals, plants, and microorganisms. Science practices in geology, physics, biology, chemistry and paleontology all contributed to the solution to this compelling mystery. Lesson plans are included that have students identify evidence and construct an explanation to tie it together. Summary questions are included at the end and a class discussion is recommended. (This activity will be the only one evaluated in this review.) Another resource is Finding the Crater where students visit different K-T boundary sites. There are also lessons where students analyze various characteristics of the asteroid such as its size and energy, chemical data about the asteroid, and the iridium fallout from an asteroid impact. A hands-on activity where students study the differences in foraminifera fossils below and above the K-T boundary is also included as well as an article that outlines more details about each of the discoveries covered in the film. You can view the film on the website or HHMI will send you a free DVD. Lesson plans including teacher notes and a student handout can be found at http://www.hhmi.org/biointeractive/following-trail-evidence.
Without the work of decomposers, living organisms would eventually use up all the raw materials in the environment, and dead organisms and wastes would pile up. This video segment from Interactive NOVA: "Earth" describes the role of decomposers as the earth's great recyclers.
In this activity, students investigate the fascinating and complex process of decomposition and lay the foundation for deeper understanding of concepts related to matter and energy transfer in ecosystems. Through exploration and discussion, students go beyond simple definitions. Instead, students discover key characteristics of decomposition as they struggle with creating a sequence for decomposing wood and leaves. They learn the difference between physical decomposition and chemical decomposition and that many things contribute to decomposition, but certain organisms are classified as decomposers. They also search for and discuss evidence of decomposers, make model diagrams to further develop their ideas about the process of decomposition, and discuss decomposition and its role in the cycling of matter. Finally, students are challenged to recognize the evidence and impact of decomposition in the ecosystems they explore.
In this video segment adapted from Navajo Technical College, meet a dendroclimatologist who studies the relationship between precipitation and tree growth in the Navajo Nation.
In this visualization adapted from the University of Massachusetts Medical School, discover the role that dengue viral proteins play in a human cell as the virus prepares to replicate.
Concluding a two-part lab activity, students use triple balance beams and graduated cylinders to take measurements and calculate densities of several household liquids and compare them to the densities of irregularly shaped objects (as determined in Part 1). Then they create density columns with the three liquids and four solid items to test their calculations and predictions of the different densities. Once their density columns are complete, students determine the effect of adding detergent to the columns. After this activity, present the associated Density & Miscibility lesson for a discussion about why the column layers do not mix.
This video segment from NOVA: A Desert Place describes the physical characteristics and organisms that define the desert biome.
This video segment from Outdoor Nevada examines threats to the desert tortoise population.