Group items tagged

The origin of viruses remains mysterious because of their diverse and patchy molecular and functional makeup. Although numerous hypotheses have attempted to explain viral origins, none is backed by substantive data. We take full advantage of the wealth of available protein structural and functional data to explore the evolution of the proteomic makeup of thousands of cells and viruses. Despite the extremely reduced nature of viral proteomes, we established an ancient origin of the "viral supergroup" and the existence of widespread episodes of horizontal transfer of genetic information. Viruses harboring different replicon types and infecting distantly related hosts shared many metabolic and informational protein structural domains of ancient origin that were also widespread in cellular proteomes. Phylogenomic analysis uncovered a universal tree of life and revealed that modern viruses reduced from multiple ancient cells that harbored segmented RNA genomes and coexisted with the ancestors of modern cells. The model for the origin and evolution of viruses and cells is backed by strong genomic and structural evidence and can be reconciled with existing models of viral evolution if one considers viruses to have originated from ancient cells and not from modern counterparts.

9:14 video Have you ever wondered how life first got started on Earth? So do scientists! Though the question has not yet been fully answered, a careful study of Chemical Evolution is beginning to shed light on this mystery. In this film you will learn what Chemical Evolution is, how it works, and how it is different from Biological Evolution.

Evolution is essential to our curriculum and to scientific literacy. To understand the big picture of biology, students need to understand life in terms of both its history and its future - the changing life forms and ecosystems that have arisen and changed over billions of years, as well as the mechanisms that brought about those changes and are shaping the future of life on Earth.

Thankfully, Caleb Trujillo over at Molecular Life Sciences has created this handy infographic, that lists the top five misconceptions about evolution, and explains (with diagrams!) why they're wrong. And it's designed to be shared - as Trujillo explained over at Version 1.0 of the infographic: "From my experience, most people who misunderstand evolution are actually misinformed about what science is and how it operates."

As the genomes of more and more species are sequenced, geneticists are piecing together an extraordinarily detailed picture of the molecules that are fundamental to life on Earth. With modern techniques, we can not only trace how the bodies of animals have evolved, we can even identify the genetic mutations behind these changes and, as we recently reported, genes sometimes evolve in surprising ways. Here though, in celebration of the versatility of DNA, New Scientist presents five classic examples of gene evolution.

The life science/biology course is divided into 12 instructional segments grouped into four sections. In the first section, From Molecules to Organisms: Structures and Processes, students develop models of how molecules combine to build cells and organisms (IS1 [Structure and Function]; IS2 [Growth and Development of Organisms]; IS3 [Organization for Matter and Energy Flow in Organisms]). In the second section, Ecosystems: Interactions, Energy, and Dynamics, students zoom out to the macroscopic scale to show how organisms interact (IS4 [Interdependent Relationships in Ecosystems]; IS5 [Cycles of Matter and Energy Transfer in Ecosystems]; IS6 [Ecosystem Dynamics, Functioning, and Resilience]; IS7 [Social Interactions and Group Behavior]). Students return to the role that DNA plays in inheritance during the third section, Heredity: Inheritance and Variation of Traits (IS8 [Inheritance of Traits]; IS9 [Variation of Traits]). The class ends tying together interactions at all these scales by explaining evolution and natural selection in Biological Evolution: Unity and Diversity (IS10 [Evidence of Common Ancestry and Diversity]; IS11 [Natural Selection]; IS12 [Adaptation and Biodiversity]). A vignette in IS12 illustrates the level of three-dimensional understanding students are expected to exhibit as a capstone of the course.

Life sciences focus on all things living, exploring the patterns, processes and relationships of organisms. The goal of life sciences is to demonstrate how unifying principles can help us to make sense of the natural world and solve problems in the world we live in. High school life sciences extend student knowledge of topics such as organisms, ecosystems, heredity and evolution, integrating a long history of scientific research from multiple fields. In high school, students will build on their conceptual understanding of life sciences by investigating and witnessing the relationships among structure and function, matter and energy, ecosystems and natural selection. Students should be able to effectively communicate facts and findings, as supported in the science literacy skills covered in the Common Core State Standards.

Shape of Life is a series of FREE short classroom videos that beautifully illustrate the evolution of the animal kingdom on planet earth. Based upon an original PBS Series, Shape of Life is especially designed for students and teachers who want a first-hand account of how animals adapt and thrive. The series is NGSS aligned with exquisite focus on diversity, biodiversity, adaptability, body structure, design, behaviors, and the innovative scientists who explore these creatures.

Shape of Life is a series of FREE short classroom videos that beautifully illustrate the evolution of the animal kingdom on planet earth. Based upon an original PBS Series, Shape of Life is especially designed for students and teachers who want a first-hand account of how animals adapt and thrive. The series is NGSS aligned with exquisite focus on diversity, biodiversity, adaptability, body structure, design, behaviors, and the innovative scientists who explore these creatures.

But now, a century and a half later, scientists from 11 different institutions have joined forces to amass all of that information, plus new data, to create the most comprehensive version of the tree so far. As detailed in a recent article in Proceedings of the National Academy of Sciences, the new Tree of Life shows how 2.3 million different types of animals, plants, fungi and microbes are interconnected, and how those relationships have diverged since life began on Earth more than 3.5 billion years ago.

This case study focuses on the intersection of defining a scientific species and defining a legal species. The compelling story of Lolita, an orca whale in captivity, is used to highlight the legal significance of species declaration. Students will work through scientific species definitions and data on Orca whales before deciding if Orca whales should be considered as one or several species. After an introduction to Lolita and a mock town hall meeting, students are thrown into the real life situation of contemplating the fate of an Orca in captivity that suddenly has protected legal status. This case was developed for use in a first-year biology course focusing on ecology, genetics, and evolution. It also could be used in upper or lower division courses on ecology, evolution, or conservation.

One of my favorite "proofs" of evolution is the recurrent laryngeal nerve (RLN)-the nerve that innervates the larynx from the brain, helping us speak and swallow. It takes a very circuitous course, looping from the brainstem down around the aorta and then back up to the larynx. Here's its course in humans:

Shape of Life is a series of short classroom videos that beautifully illustrate the evolution of the animal kingdom on planet earth. Based upon an original PBS Series, Shape of Life, is especially designed for students and teachers who want a first-hand account of how animals adapt and thrive.

A team of scientists unveiled a new tree of life on Monday, a diagram outlining the evolution of all living things. The researchers found that bacteria make up most of life's branches. And they found that much of that diversity has been waiting in plain sight to be discovered, dwelling in river mud and meadow soils.

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.

This case study teaches students about allopatric speciation through an investigation of the benthic and limnetic sticklebacks of Paxton Lake, which are among the youngest species on Earth, diverging from each other after the Pleistocene glaciers melted and the Gulf Islands formed. Researchers at the University of British Columbia have carried out a variety of fascinating studies on these hardy little fish. Results from this research (formatted as data sheets included in the teaching notes) are provided to students who design experiments and then compare actual data to investigate why benthic and limnetic sticklebacks seldom interbreed in Paxton Lake. Developed for a first-year biology course for majors organized around the general theme of evolution and the history of life on Earth, this case study is an updated version of another case in the collection, "Something's Fishy in Paxton Lake" (Sharp, 2001). The current version is especially suited for a flipped classroom in which students prepare for class ahead of time with a reading assignment that also involves the viewing of a video by the case authors that introduces the mechanisms of allopatric speciation.

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.

This animated short video tells the story of Alfred Russel Wallace, who independently formulated the theory of evolution by natural selection at the same time as Charles Darwin.Co-directed by Flora Lichtman and Sharon Shattuck of Sweet Fern Production, the video tracks A. R. Wallace's life from growing up in England to his voyages with Henry Walter Bates and later adventures in the Malay Archipelago. The 8-minute video ends with an examination of the naturalist's legacy. (The video is presented here with permission from Sweet Fern Productions.)

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

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.

Video segments describing evolution in engaging cartoon format