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In biology classes, students are typically taught that spontaneous generation does not take place. And yet, at the origin of life, life had to arise without parents from abiotic processes. What were those processes that gave rise to the first life?  This case study uses an interrupted format to guide students through the Miller-Urey experiment of 1953, which showed that organic molecules could be produced from abiotic precursors and conditions thought to be prevalent on the early Earth. The case also addresses the more speculative implications about where these reactions may have taken place to create the organic building blocks of life on this planet. The first three parts of the case, which explore the Miller-Urey experiment, are ideal for introductory biology courses and take about 45-50 minutes to complete. The remaining sections, which explore whether such chemical reactions took place in outer space, were used in a non-major astrobiology course and require a further hour to complete.

Watch this video (6:30), play with the interactive version of the 'Tree of Life' and sign up to Tree of Life updates at http://www.wellcometreeoflife.org. This six-minute Tree of Life video appeared on the BBC One programme 'Charles Darwin and the Tree of Life' narrated by David Attenborough.

Origin of life - volcanic pools - ocean floor - outer space

Part 2 of 2. David Attenborough explains how early sea life developed and adapted to dry land, becoming Reptiles and Amphibians. After the era of the Dinosaurs came to a sudden end, Mammal species began to proliferate. From BBC 1 documentary 'Charles Darwin and the Tree of Life'.

This "clicker case" tells the story of "Hannah," a baby girl adopted by two loving parents who grows up with an uncontrolled appetite and develops severe early-onset obesity. Students follow Hannah's story as she develops excessive eating early in life, which her health care team is unable to explain. A visit to obesity specialists finally reveals the underlying cause of Hannah's obsession with food: extremely low levels of circulating leptin, a hormone that regulates appetite and body weight. It is further discovered that Hannah's leptin deficiency is due to a mutation in the LEP gene. As the story unfolds, students first work on unit conversions and BMI calculations to practice quantitative skills as well as graph and data interpretation skills. Students then apply their knowledge of DNA transcription, translation, and protein structure to answer questions based on figures from a 2019 study on LEP mutations. The case is best suited for high school and lower-level undergraduate biology courses.

In this article, we'll examine scientific ideas about the origin of life on Earth. The when of life's origins (3.53.53, point, 5 billion years ago or more) is well-supported by fossils and radiometric dating. But the how is much less understood. In comparison to the central dogma or the theory of evolution, hypotheses about life's origins are much more...hypothetical. No one is sure which hypothesis is correct - or if the correct hypothesis is still out there, waiting to be discovered.

Darwin's theory of biological evolution helps us understand how simple life forms can give rise to complex lifeforms, but how did the first reproducing creatures come about? The origin of life needs its own explanation.

Origins of life with self-replicating molecules

It is, when you think about it, sort of weird that nearly all mammals lose the ability to digest milk early in life. The Class Mammalia is, after all, defined by the gland that produces this life-giving fluid-supplier not only of necessary nutrients but also of water and molecules that protect against continual assaults from invading organisms.

Dr Adam Rutherford discusses the early evolution of complex life on Earth with geneticists Professor Steve Jones and Dr. Nick Lane.

Paul Andersen discusses scientific evidence of the origin of life on our planet. He begins with a brief discussion of the age of the earth and ends with the future of humanity. He includes geologic, chemical and molecular data.

Every year, it inflicts between 250,000 and 500,000 helpless and malnourished young people with early-life blindness. And in half of those cases, it also brings death, according to the World Health Organization. Vitamin A deficiency also puts pregnant women at risk. It's rare in developed countries, but the goal of completely eradicating vitamin A deficiency - mostly in Africa and Southeast Asia - remains unmet. Scientists are now working to genetically engineer "super" bananas that are fortified with crucial alpha- and beta-carotene, which the body converts to vitamin A.

The early stages of embryonic development shape our cells and tissues for life. It is during this time that our newly formed cells are transformed into heart, skin, nerve or other cell types. Scientists are finding that this process is largely controlled not by the genome, but by the epigenome, chemical markers on DNA that tell cells when to turn genes on and off. Now, studying zebrafish embryos, researchers at Washington University School of Medicine in St. Louis have shown that the epigenome plays a significant part in guiding development in the first 24 hours after fertilization.

Like humans, some golden retrievers develop Duchenne muscular dystrophy (DMD), a hereditary muscle wasting condition that begins early in life. Using gene therapy, scientists were able to restore muscle function in dogs with the disease, according to a study published today (July 25) in Nature Communications.

n this interrupted case study, students learn about the influence of early fetal nutritional conditions on the expression of genes related to metabolism and growth. Beginning with the true event of a food and fuel embargo that led to famine in the western Netherlands toward the end of World War II, students learn about the historical background of the Dutch Hunger Winter and its social impact. Using real data from the study conducted by Heijmans and coauthors (2008), students then compare the methylation level of a specific gene between individuals conceived during the famine and their unaffected siblings, and how changes in the expression of this metabolically important gene may impact the risk of developing type 2 diabetes. Supported by other studies on mice and in humans, students conclude that in utero events may impact the health of individuals later in life through epigenetic mechanisms. The case is ideally suited for a molecular or cell biology course, but is also appropriate for an introductory biology course in which students have an understanding of descriptive statistics, interpretation of statistical test results, eukaryotic gene structure, and regulation of gene expression.

article summarizing key findings

3 min Over billions of years, Earth has developed essential properties that allowed living organisms to form.