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JoAnn Burkholder and her associates at North Carolina State University were the pioneer investigators in the Pfiesteria research, which our group of Old Dominion colleagues has since pursued. Burkholder was the first scientist to link the 1991 fish deaths to Pfiesteria, based on her team's on-site investigations and controlled laboratory studies. In addition, she observed a complicated life cycle in the organism, including numerous morphological forms such as motile flagellated cells, amoebae and cysts that are able to survive in the sediment of estuaries until activated by the presence of fish to produce toxic motile cells. 

In population genetics, gene flow (also known as gene migration) is the transfer of alleles or genes from one population to another. Migration into or out of a population may be responsible for a marked change in allele frequencies (the proportion of members carrying a particular variant of a gene). Immigration may also result in the addition of new genetic variants to the established gene pool of a particular species or population.

In this tutorial you will be learning about the Linnaean system of classification used in the biological sciences to describe and categorize all living things.  The focus is on finding out how humans fit within this system.  In addition, you will discover part of the great diversity of life forms and come to understand why some animals are considered to be close to us in their evolutionary history.

This case study provides an overview of the seminal experimental work that led to the discovery of DNA structure and the confirmation of the semi-conservative model of DNA replication. By guiding students through a chronological series of historic experiments and discussing some of the collaborations and controversies involved in the original research, students learn about the history and nature of science in addition to several important biological concepts. A number of recommended videos, including one created by the author, enable instructors to use the "flipped-classroom" mode of instruction according to which students read primary literature and watch videos on their own before group discussions and activities. The case study was developed for use in an introductory undergraduate biology course, and would also be appropriate for use in a high school biology course. Some prior knowledge or instruction may be required, depending on the level and learning objectives of the course.

"Bioethics modules serve as a guide for teachers who want to incorporate an in-depth analysis of bioethical issues and debates into their life sciences, social sciences, public policy, or theology courses. They provide lesson plans that teachers can use to lead classes and discussions on topics in bioethics. Within each module, you will find background information, readings, suggested classroom procedures and activities, and links for additional information and resources."

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.

This case study is designed to help students learn about the ecosystem services of Earth (Biosphere 1) by examining the challenges faced by the designers who tried to replicate its components in Biosphere 2. In 1991, four men and four women entered Biosphere 2, a man-made closed ecological system in Arizona, to see if eight biospherians could be sustained by this miniature version of Biosphere 1. The project succeeded in producing most of the food needed, but required additional oxygen before the end of the two-year experiment. After an introduction to Biosphere 2, students learn about the four main types of ecosystem services and discuss how Biosphere 2 might provide these services. At the end of the case, students calculate their own ecological footprint, demonstrating how humans are overreaching the ecosystem services of Biosphere 1, just as the biospherians could not be sustained by the ecosystem services included in Biosphere 2. The case is suitable for an introductory undergraduate course in biology, ecology, or environmental science.

n. As such, this set of Essential Elements addresses a small number of science standards, representing a breadth, but not depth, of coverage across the entire standards framework. The purpose of the DLM Essential Elements is to build a bridge from the content in the general education science framework to academic expectations for students with the most significant cognitive disabilities. This version of the Essential Elements will provide content for science assessments for at least the next two years. The DLM Science Consortium intends to develop a learning map based on research about how students learn science content and engage in scientific and engineering practices in the next phase of the project. Revisions will be made when the science map is complete, at which time we anticipate the EEs will be aligned to the map with revisions and additions as appropriate.

Symbiotic relationships are interactions between species that live closely with each other and are commonly separated into three types: parasitism, mutualism, and commensalism. Students are often under the impression that these types are distinct and mutually exclusive, but on closer examination some interactions appear to be at times mutualistic, at other times parasitic. Is it perhaps better to think of mutualism and parasitism as two ends of a sliding scale, with commensalism in the middle? In this case study, students consider this question by examining what is often considered to be a classic example of mutualism existing between oxpecker birds and African savanna large mammals. After students examine data from a research study on oxpecker behavior, they then apply a more nuanced understanding of species interactions to a set of additional scenarios. The learning objectives for the case align with the Four-Dimensional Ecology Education Framework. The case was written for an upper-level undergraduate ecology course, but could easily be adapted for an introductory biology course.

For anyone with a deep, enduring faith in the meaning of nature, it may come as something of a shock to learn that the word "natural" means nothing at all-at least when it comes to the business of marketing processed food. Every year, U.S. corporations sell tens of billions of dollars worth of food products labeled as "natural." Yet, to this day, the Food and Drug Administration has never formally defined the term. The word is a kind of orphan child, undefined by government, misused by industry and without a provenance or a use for the average American consumer.

Brief online animation, followed by 5 question quiz