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What does it mean to be 'alive'? At a basic level, viruses are proteins and genetic material that survive and replicate within their environment, inside another life form. In the absence of their host, viruses are unable to replicate and many are unable to survive for long in the extracellular environment. Therefore, if they cannot survive independently, can they be defined as being 'alive'?

This interrupted case study introduces the topic of bacterial sporulation and cannibalism in Bacillus subtilis. The storyline follows Susan and her lab mates who are presenting research at a lab meeting when Susan falls asleep and dreams they are stranded on a deserted island. She makes connections between their fight for survival in the dream and the survival mechanisms of the bacteria they study in the lab. The benefits of sporulation under conditions of sustained stress are fairly obvious, but Susan's dream is used to examine the idea that sporulation may not always be beneficial and that bacteria would not want to commit to entering such a state in response to temporary stresses. Through the analysis of actual data from the scientific literature, students uncover a mechanism by which B. subtilis delays its commitment to sporulation by killing members of its own species to release nutrients (i.e., cannibalism). Originally developed for a general undergraduate microbiology course when discussing the structure and growth of prokaryotic cells, the case could also be used in an introductory biology course that emphasizes bacteria and data literacy.

This case study describes the daily osmotic struggle for survival faced by hummingbirds. The narrative is written from the viewpoint of a human observer who sees an Anna's hummingbird feeding on flowers outside of her window.  She notices that the birds mostly feed early in the morning and again in the evening at dusk; midday encounters are rare.  The case raises questions about floral nectar production, how this correlates to feeding bouts, and how this in turn correlates to the daily osmotic challenges faced by these nectarivorous birds and their allies (sunbirds). Students will learn about renal adaptations for survival and how they operate. Finally, since hummingbirds have a high metabolic rate and cannot feed overnight they undergo torpor during this time, an energy saving physiologic state.  Students read journal articles to answer case questions, which should lead them to a better understanding of the related physiological processes of osmoregulation, metabolic rate and torpor.

This 8-minute video is derived from the 2013 Holiday Lectures on Science. In it, Dr. Charles Sawyers explains the difference between proto-oncogenes, oncogenes, and tumor suppressor genes, and how mutations in these genes drive cancer development. "Cancer genes" can affect several cellular processes that he groups into three categories: cell growth and survival (i.e., genes involved in the cell cycle, cell fate (i.e., genes involved in cell differentiation), and genome maintenance (i.e, genes involved in DNA repair.)

This directed case study follows two college roommates, Darrell and Anthony, who have just returned to school after winter vacation. They share that their ageing fathers are concerned about their declining faculties and are amused by their fathers' efforts to reverse the process.  Darrell's dad plays "brain games" on the computer while Anthony's father believes running will slow his memory decline. Intrigued, the roommates search through their biopsychology class notes to find out whether their fathers are correct. They review the topics of synaptic formation and plasticity, including axonal and dendritic development, and chemical factors in the brain that promote the survival and growth of neurons or stop the genetically programmed death of neurons. Based on research findings, students reading this case will decide whether Darrell and Anthony's fathers are correct in their assertions. The case is appropriate for a wide variety of courses including introductory anatomy or physiology, or for upper-division biopsychology, biology, or neuroscience courses.

In a creative stroke inspired by Hollywood wizardry, scientists from Harvard Medical School and Technion-Israel Institute of Technology have designed a simple way to observe how bacteria move as they become impervious to drugs. The experiments, described in the Sept. 9 issue of Science, are thought to provide the first large-scale glimpse of the maneuvers of bacteria as they encounter increasingly higher doses of antibiotics and adapt to survive - and thrive - in them.

Explore the diversity and evolution of birds with this web interactive based on the Wall of Birds mural. Envisioned by Cornell Lab ornithologists and realized by artist Jane Kim, the large-scale mural features species from all surviving bird families alongside a select group of extinct ancestors.

CRISPR still has a long way to go before it can be used safely and effectively to repair-not just disrupt-genes in people. That is particularly true for most diseases, such as muscular dystrophy and cystic fibrosis, which require correcting genes in a living person because if the cells were first removed and repaired then put back, too few would survive. And the need to treat cells inside the body means gene editing faces many of the same delivery challenges as gene transfer-researchers must devise efficient ways to get a working CRISPR into specific tissues in a person, for example. CRISPR also poses its own safety risks. Most often mentioned is that the Cas9 enzyme that CRISPR uses to cleave DNA at a specific location could also make cuts where it's not intended to, potentially causing cancer.

The number of new Ebola cases is tapering off, but the search for new treatments continues. Now, one research team has found potential drug candidates that successfully treated up to 90 percent of mice exposed to the Ebola virus. They report their findings in the journal ACS Infectious Diseases.

A multicenter study has identified an FDA-approved medication that prolongs survival in mice with diffuse intrinsic pontine glioma, a brain tumor that now lacks chemotherapy treatments.

A study in monkeys offers the first evidence that a leading drug developed to fight Ebola works against the strain causing the current outbreak in West Africa. Six animals were infected with a very high dose of the virus and then, three days later, half were given the drug, TKM-Ebola-Makona, which was designed specifically to fight the West African strain. The monkeys that received the drug survived, but all three untreated monkeys died, researchers reported on Wednesday in the journal Nature.

Microbes 2,500 meters below the seafloor in Japan are most closely related to bacterial groups that thrive in forest soils on land, suggesting that they might be descendants of ones that survived when their terrestrial habitat was flooded 20 million years ago

National geographic site with high school lessons on: - captive breeding, species survival, and case studies. -Video clips are also available

For at least 10,000 years, humans have been cultivating plants and selectively breeding them for fast growth, pest resistance, long-term survival in storage, and bigger and better fruit. We've been domesticating animals for just as long, selecting for traits that suited our needs, such as size, appearance, or even personality. For a few decades, we've also had genetic engineering methods for getting the characteristics we want in plants, animals, and microorganisms.

"Survival of the Fittest: Variations in the Clam Species Clamys sweetus" is a guided inquiry. This series of hands-on activities complements the HHMI DVD Evolution: Constant Change and Common Threads and requires simple materials such as M&Ms, Reese's Pieces, food storage bags, and paper cups. This activity has been designed to engage students in thinking about the mechanism of natural selection by encouraging them to formulate questions that can be answered through scientific investigation, data collection, and pattern recognition.

Nitrogen is one of the primary nutrients critical for the survival of all living organisms. Although nitrogen is very abundant in the atmosphere, it is largely inaccessible in this form to most organisms. This article explores how nitrogen becomes available to organisms and what changes in nitrogen levels as a result of human activity means to local and global ecosystems.

Human-engineered microbes are workhorses of the pharmaceutical and chemical industries, churning out biofuels, drugs, and many other products. But they can cause big problems if they become contaminated by other microbes or viruses or escape into the environment. Now, a new type of microbe that can survive only on artificial nutrients promises better security against such mishaps. The strategy, described in two papers in this week's issue of Nature, might ultimately be used to control genetically engineered plants or other organisms released into the wild to create products or clean up pollution.

Gregory Lanzaro, medical entomologist and professor at University of California Davis (UC Davis) and leader of the research team behind the discovery, says they are calling the hybrid mosquito a "super" mosquito because it can survive exposure to the insecticides used to treat bed nets. He and his team report their findings in the Proceedings of the National Academy of Sciences.

3:14 video November 7, 2011 - Watch as biologist Luke Dollar uses a blowgun to subdue and study Madagascar's top predator, the fossa. The catlike creature "will eat pretty much everything in the forest," but to survive, it'll still need help from conservationists like Dollar, a National Geographic Emerging Explorer.

cartoon strip of crickets