Learn node: Burgess Shale “is the world’s most important fossil fauna”

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Posted on 18th January 2008 by Judy Breck in biology | paleontology

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The map illustrating this learn node, from the University of California Museum of Paleontology, shows the Cambrian Period 500 million years ago and explains: “The location of the Burgess fauna is indicated by a star on the continent of Laurentia (western North America). Notice that Canada is located just south of the equator!” A Smithsonian web exhibit called Strange Creatures: A Burgess Shale Fossil Sampler begins: “more than half a billion years old, the fossils of the Burgess Shale preserves an intriguing glimpse of early life on Earth.” Britain’s Open University includes the Burgess Shale in a Science and Nature course on the Cambrian explosion.

The Burgess Shale became well known to the public through the late Stephen Jay Gould’s 1990 best selling book Wonderful Life: The Burgess Shale and the Nature of History. The fossils in the Burgess Shale have evoked awe and controversy over the century since they were first discovered.  Images CambrianCalled “Showdown on the Burgess Shale,” two lectures in The Unofficial Stephen Jay Gold Archive provide a framework for learning some of the basic ideas and issues for the evolution of life. The first lecture is “The Challenge” by Simon Conway Morris which is followed by Gould’s “The Reply.” In the latter, Gould writes:

The Burgess Shale, in the Canadian Rockies, contains the world’s most important fossil fauna—a detailed and exquisite record (with rarely preserved soft parts included) of marine life about 520 million years ago, just following the Cambrian explosion and therefore permitting us to census the results of this seminal episode in the history of animal life on earth.

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Learn node: Butterfly brains, journeys and birth to observe online

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Posted on 18th January 2008 by Judy Breck in biology | brain

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In this learn node illustration you are seeing structure inside a Monarch butterfly brain. It is from a research article in PLOS Biology on what may underlie sun compass navigation, shown on this page in Figure S10. CRY2 RNA Distribution in Monarch Brain. If the circadian clock mechanism of butterfly brains seems too detailed for what you want to learn or teach now, you could find less specialized material in the latest news on Monarch Butterfly migration and Journey North. Each of these butterfly sources provides links to other good materials about these beautiful insects. So does this Wikipedia Monarch butterfly article, which includes a reference to the video below of a Monarch butterfly emerging from its chrysalis. Within the brain of the emergent baby butterfly is the RNA that science is learning will inform his flight north, guided by the sun. All of these materials are open, free, richly connected nodes in the global learning commons.


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Learn node: Chameleons, optics and the most distinctive reptile eyes

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Posted on 12th January 2008 by Judy Breck in animals | biology

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Chameleon

The image for this learn node is a chameleon from an animation in the terrific tutorial Optics for Teens created and hosted online by the Optical Society of America. If a look through the tutorial makes you curious to learn more about optics, a full Optics course is offered by MIT Open Courseware (tree illustration from Lec# 3).Tree If your interest is roused to know more about chameleons the report of scientists developing computer models for learning about chameleon habitats in Madagascar is offered here by the American Museum of Natural History. And you can learn a lot more about these amazing lizards at the San Diego Zoo’s Chameleon page. There the optical mastery of chameleons is described:

The chameleon’s eyes are the most distinctive among the reptiles. Each eye has a scaly lid shaped like a cone, with only a small, round opening in the middle for the pupil. The chameleon can rotate and focus its eyes separately to look at two different objects at the same time! This gives it a full 360-degree view around its body. When the chameleon sees prey, both eyes can focus in the same direction to get a clearer view.

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Learn node: Neurons may remove motion blur

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Posted on 28th December 2007 by Judy Breck in biology

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motionblur.jpgThe first source in this learn node is an article the open access journal Public Library of Science Biology in which researchers explore how at the neural level we may sharpen what we see in the presence of eye movements. The journal’s December 2007 issue’s table of contents features the image shown to the left, with this explanation:

Our eyes are constantly moving, which blurs the image of the world across the retina. Shown here is a neural network model of the visual cortex that removes this motion blur by using neural connections that are matched to the statistics of eye movements. (see Pitkow et al., e331).

To learn more about where seeing occurs, Webvision has a discussion of “Roles of amacrince cells,” which are “cells of the vertebrate retina [which] are interneurons that interact at the second synaptic level of the vertically direct pathways consisting of the photoreceptor-bipolar-ganglion cell chain.” Just to take a peek at how the eye works, or to study in detail, the amacrince page is an excellent open resource created at the John Moran Eye Center, University of Utah: WEBVISION: The Organization of the Retnia and Visual System.

The University of Texas also has some outstanding online materials for learning about motion perception, including this page in a Center for Perceptual Systems. Even for beginning and young students, spending some time with webpages like these introduces basic ideas and tickles the curiosity about vision and the biology from which it arises.

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Learn node: Meerkat facts, play and scorpion dismemberment

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Posted on 16th November 2007 by Judy Breck in animals | biology | environment

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meerkat rock alertThis learn node points to facts about the mammal Suricata suricatta, known as the meerkat, that are set out with excellent images (including the one to the right) in the Animals pages of Utah’s Hogel Zoo website. There are more facts at the Meerkat Information page of a zoological park that cares for meerkats who need a home. An article in the magazine of the American Museum of Natural History, Natural Science, by Lynda L. Sharpe is an expert description of some of what is known about the animal’s behavior: Meerkats At Play: Evolution demands that activities costing a lot of energy provide survival value in return. But what do these rambunctious little mammals gain from having so much fun?

Meerkats have their learning duties as well as frequent recess. A Live Science report (with amazing pictures) describes: Hunting 101: Meerkats Teach Scorpion Dismemberment in which a seventy-day-old pup learns how to eat a scorpion fed to it live. Only the not squeamish click here.

Within the webpages mentioned are links to more sources chosen by the page authors. Like their burrows, the online network about meerkats is complex and connects among various chambers of information.

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Learn node: Brainbows add color to neuron viewing

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Posted on 6th November 2007 by Judy Breck in biology

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brainbow neuronsThe image in this learn node of mouse neurons of many colors is from a Harvard Science video called Somewhere, inside the Brainbow which you can view by clicking its title in this sentence. The accompanying HARVARDSCIENCE article here overviews the project, which is led by Harvard’s Jean Livet, Joshua R. Sanes, and Jeff W. Lichtman. The article explains:

By activating multiple fluorescent proteins in neurons, neuroscientists at Harvard University are imaging the brain and nervous system as never before, rendering their cells in a riotous spray of colors dubbed a “Brainbow.” . . .

“There are few tools neuroscientists can use to tease out the wiring diagram of the nervous system; Brainbow should help us much better map out the brain and nervous system’s complex tangle of neurons,” Lichtman said.

Equal parts pointillism, fauvism, and abstract expressionism, the resulting images could also help scientists identify how brain wiring goes awry in many different diseases. Brainbow could also help track the complicated development of the mammalian nervous system, currently understood only in general terms. This, in turn, could elucidate the origins of the many brain disorders that arise early in development.

Drawing upon a mix of genetic tricks and special proteins that cause cells to glow, Brainbow uses a well-known genetic recombination system known as Cre/lox in a new way, to shuffle genes encoding green, yellow, orange, and red fluorescent proteins. The researchers painstakingly assembled the Brainbow transgene from snippets of DNA, and inserted it into neuronal DNA. As they predicted, the cut-and-paste recombination occurred totally at random, in the process assigning scores of different colors to neurons. This variation makes neurons leap out from one another visually under ordinary confocal microscopy.

Photonics.com picked up on the Brainbow story from the scientific imaging perspective, with an article called ‘Neurons Glow in ‘Brainbow’: “Brainbow allows researchers to tag neurons with roughly 90 distinct colors, a huge leap over the mere handful of shades possible with current fluorescent labeling. By permitting visual resolution of individual brightly colored neurons, this increase should greatly help scientists in charting the circuitry of the brain and nervous system.”

Chemistry World calls its report on this research Brain’s wiring seen in Technicolor, and includes nine still images of different Brainbow perspectives.

If you visit the the Brainbow links above, and others such as a report today in the New York Science Times, you will note that they all mention that Brainbow is the cover story of this week’s Nature magazine. The report in Nature magazine is not, however, a learnode (a node for learning in the open Internet) because it is not open. All of the other sources mentioned, and the supplementary links that they offer are open. What makes Nature not open is more than the fact that it is closed except to paid subscribers and purchasers of its Brainbow article. The Nature article is also not open because it cannot be a node in a network cluster of Brainbow links. Only open links can be learnodes in subject clusters where the links enrich each other and keep each other up-to-date. By analogy to the neuron image above: the open articles interconnect like the different colored neurons do; the Nature article is an isolated dot with no extending dendrite.
GOTO more biology learn node clusters.

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Learn node: Caring for our smallest pets

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Posted on 25th October 2007 by Judy Breck in animals | biology

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guinea pig patientTufts University offers Opencourseware like sample in this learn nod for a variety of scientific and other subjects. One of the courses, which you can click to is Rodent and Small Mammal Medicine. The webpage that a click will lead you to has valuable information on the diseases and treatment of the smallest animals we humans keep as pets. It also has this quotation from from David L. Graham, D.V.M. PhD.:

Now, ponder, please that thought of the Bard’s “what’s in a name?” Like, for example, “Pocket Pets”? In my humble opinion all veterinarians should abjure use of the term “pocket pets.”it is (at least to me and few colleagues) offensive and denigrating to the inherent uniqueness and dignity of those creatures that happen to be of such small size that they can fit into a pocket. The term suggests that such pets can be maintained in a more casual and less careful, less caring, and less thoughtful manner than is required for maintenance of other, more traditional companion animal species. Such creatures are of no lesser biological and moral consequence than are larger, more traditional pets. I’m sure that the cute alliteration of the term is a major reason for its acceptance, but I urge that some other rubric(s) be coined under which to group these relatively diminutive companion animals. Please, they are sugar gliders, gerbils, hedgehogs, mice (‘wee sleekit beasties’ – R. Burns), small pets, little small animals (to differentiate them from dogs and cats which are merely ’small animals’), minipets -but please-not “pocket pets.”

How to care for the type of smallest pets shown above guinea pigs is explained in detail at the ASPCA website. The ASPCA pages are an excellent place to study many pet subjects. The Humane Society has an article How to Care for Hamsters that contains some history and social facts too about these smallest pets. While guinea pigs are of South American origin and have been kept as pets for centuries, hamsters were “living in relative obscurity until just 70 years ago when a zoologist discovered a family of these rodents in the Syrian desert.” The ASPCA tells us guinea pigs want to live together; the hamster article said a hamster needs privacy “from others of his kind.” Respecting rodent social mores is important in their care.

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Learn node: Methicillin-resistant Staphylococcus aureus (MRSA): wash your hands!

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Posted on 23rd October 2007 by Judy Breck in biology | health | sciences

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methicillin resistant illustration

This learn node illustration is from John Hopkins Bloomberg School of Public Health’s course on Public Health Biology: page 26 of Lecture 5 (PDF). The Johns Hopkins course is an excellent source for learning about how diseases infect us, how they make us sick. and how they can become resistant to drugs. A particularly lethal bacteria is very much in the news for its drug resistance: Methicillin-resistant Staphylococcus aureus (MRSA). An excellent primer on MRSA can be found at the online Mayo Clinic.

We all want to know how to keep the bacteria from finding us and making us sick – or even killing us. Today the New York Times published answers to many of our questions about how to stay well as this superbug bacteria gets more resistant and more wide-spread.

As you have probably been hearing and reading, washing our hands is a key way to keep safe from the superbugs. Below are links to webpages reviewing how and why do to that. One of the things I learned from finding them is to use the towel I dry with to turn off the faucet: it protects from reinfecting my hands (makes sense).
How To Wash Your Hands (video)
The National Food Service Management Institute
Center for Disease Control and Prevention
Caught Dirty-Handed MicroWorld games

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Learn node: Lady bugs as green troops: beetle (Coleoptera) study and variety

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Posted on 22nd October 2007 by Judy Breck in animals | biology | ecology | environment

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beetle anatomy diagram

Lady bug star in this learn node, noting that this week 720,000 lady bugs were released by groundskeepers to find and kill pests harming plants and grass at a major New York City housing complex. Ladybugs, also called lady beetles, are natural enemies of many insects, especially aphids and other sap feeders. The beetle brigades are being used in the New York project to protect the greenery without using chemical insecticides. The tiny bugs are awesome predators: one lady bug can eat as many as 5000 aphids in her lifetime. Not only ladybugs are serving as beetle battlers for the green world. For another example, a Michigan report describes how beetles take a bite out of purple loosestrife.

There are an awful lot of beetles � and a lot beetle websites, often with titles including their scientific order name Coleoptera. The Coleopterists Society home page begins: “We live in the age of the beetles: Beetles, the insect order Coleoptera, are the dominant form of life on earth. One of every five living species of all animals or plants is a beetle! . . . ” Many of the beetle species have shown up online; for one example there are the beautiful Bembidion �where the webpage is the direct presentation of a scientist who is a leading expert on the species he showcases.

The beetle breakout of body parts in the image above is from a Russia Zoological Institute Beetles (Colelptera) and Coleopterists exhibit. From anatomy to poetry and ecology to jewelry, the exhibit showcases our human fascination with the dominant form of life on earth.

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Learn Node: Journey with the Whopping Crane migrations

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Posted on 20th October 2007 by Judy Breck in animals | biology | ecology | sciences

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whooping crane chick journey north
The bird in this learn node is Crane #722 who is now participating in her first Journey South. She hatched on May 21, 2007 and is a member of 2007 Autumn Release Group III of captive-born whopping cranes who this fall are on their 1st migration, led by ultralight planes . She is part of the Journey North Whooping Crane adventures in which new online participants (you) are invited to take part. The wonder of the many Journey North global studies of wildlife migration and seasonal change in which many thousands of students and nature enthusiasts have participated for more than a decade is that their subjects are real. You can, for example, visit the Journey North monarch butterfly migration map to see where the great winged beauties have been sighted this fall as they are moving toward Mexico to winter there.

Crane #722 is playing a role in efforts to reestablish whooping cranes, who had almost become extinct in the 20th century. We are learning from her more general lessons about migration of birds. For more on that, there is a student project on The Mystery of Bird Migration in these MIT engineering class materials and even more in this lecture on migration and navigation.

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