LExEN

Key takeaways

LExEN belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect LExEN to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of LExEN from memory before moving on to harder problems.

Reference excerpt

LExEN, an acronym for Life in Extreme Environments, is a research program overseen by the National Science Foundation. It was originally developed by G. Michael Purdy in 1997 as an area of research in which scientists could seek funding for activities in the polar regions. Participating were the Directorates for Biological Sciences, Mathematical and Physical Sciences, Engineering, Geosciences, and the Office of Polar Programs of the National Science Foundation. The program sought to place a strong emphasis upon those life-supporting environments that exist near the extremes of planetary conditions. The study of extreme habitats, both planetary and extra-planetary, was underpinned by the idea that "deep understanding of certain earth-bound microbial systems would provide important insights into life-sustaining processes and the origin of life on our own planet, while illuminating the search for life in other planetary environments." In 1999 it was announced that the future of LExEN was still under consideration but despite the lack of research in the topic, the program no longer appears on the NSF A-Z Index of Funding Opportunities.

LExEN Award Winners Jan P. Amend Washington University in St. Louis Growth Media for Hyperthermophiles: Geochemical Constraints on Realistic Carbon and Energy Sources in Shallow Marine Hydrothermal Systems Ariel D. Anbar University of Rochester Biogenic Fractionations of Transition Metal Isotopes: Novel Methods for the Examination of Life in Extreme Environments Douglas H. Bartlett Scripps Institution of Oceanography Characterization of the Upper Pressure Limits for Microbial Life Don K. Button University of Alaska Characteristics of Bacteria Native to Extremely Dilute Environments David A. Caron Woods Hole Oceanographic Institution Protistan Biodiversity in Antarctic Marine Ecosystems: Molecular Biological and Traditional Approaches James P. Cowen University of Hawaii Collaborative Research: Development of Capability to Measure Proxides of Microbial Activity Within Ocean Crust Christian H. Fritsen Montana State University Collaborative Research: Microbial Life within the Extreme Environment Posed by Permanent Antarctic Lake Ice John E. Hobbie Marine Biological Laboratory Ecology of Microbial Systems in Extreme Environments: The Role of Nanoflagellates in Cold and Nutrient-Poor Arctic Freshwaters Holger W. Jannasch Woods Hole Oceanographic Institution New Physiological and Phylogenetic Types of Hyperthermophiles at Deep-Sea Hydrothermal Vents Eric L.N. Jensen Arizona State University Prospects for Life on Planets in Binary Star Systems James F. Kasting The Pennsylvania State University. Collaborative Research: Methanogenesis and the Climate of Early Mars Douglas N. C. Lin University of California Habitable Planets and Satellites in the Outer Solar System Derek R. Lovley University of Massachusetts Fe (III)-and Humics-Reducing Microorganisms in Extreme Environments George W. Luther University of Delaware Collaborative Research: Pyrite, a Crucial Mineral and Surface for Microbial Life in Extreme Hydro thermal Environments Tullis C. Onstott Princeton University A Window Into the Extreme Environment of Deep Subsurface Microbial Communities: Witwatersrand Deep Microbiology Project Frederick A. Rainey Louisiana State University Combining Culturing and Non-Culturing Approaches for the Isolation of Prokaryotes from a Hyper Arid Desert Environment William S. Reeburgh University of California Experimental Studies on Hydrogen Biogeochemistry in Anoxic Environments John N. Reeve Ohio State University Longevity and Diversity of Microorganisms Entrapped in Tropical and Polar Ice Cores David A. Stahl Northwestern University Diversity and Habitat Range of Sulfate-Reducing Microorganisms Gordon T. Taylor SUNY at Stony Brook Biology and Ecology of South Pole Snow Microbes Thomas C. Vogelmann University of Wyoming The Snow Alga Chlamydomonas nivalis: Photosynthesis Under the Greatest Extremes of High Light, UV-B Radiation and Low Temperature on Earth Russell H. Vreeland West Chester University Paleobiology of Ancient Salt Formations: Examination of Primary Crystals for Biological Materials

See also List of ecology awards List of environmental awards

References

Worked examples

Example 1 — a first encounter with LExEN

Start with the simplest possible case. Write down what LExEN claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to LExEN before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about LExEN ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of LExEN

In research: LExEN appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses LExEN in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: LExEN is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ecology awards, Environmental sciences awards, National Science Foundation, so understanding it makes those chapters shorter.
In everyday life: Look for LExEN outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study LExEN in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what LExEN means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain LExEN out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is LExEN in simple terms?

LExEN, an acronym for Life in Extreme Environments, is a research program overseen by the National Science Foundation. It was originally developed by G.

Why does LExEN matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study LExEN?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on LExEN.