Category Archives: IBDP Biology
Inside Nature’s Giants
Channel 4’s fantastic series has just ended in the UK (I’m back for a holiday), and I can’t wait for the DVD. This is the kind of natural history quality that the BBC normally has a monopoly on, but C4 have presented something outstanding here.
Fin Whale Dissection
Over the four episodes, Mark Evans presents dissections of four giants of the animal world: elephant, whale, crocodile and giraffe. On hand is the expert anatomist Joy Reidenberg, who does a great job of taking apart and explaining their findings. Richard Dawkins takes the opportunity to point out some of the wonders of evolution in the animals, using anatomical and computer-graphic explanations. It’s great.
Embedded below are part one and part two of the second episode: fin whale. Rather than dissect at the Royal Veterinary College as normal, their challenge was to dissect this whale which washed up on the coast of Ireland before it exploded with decomposition.
If you can get 4onDemand, all four episodes are available online for a month. They are not available for download, but to really get the full effect, you need a high-quality image – so fingers crossed for the DVD!
For now, visit the official website for some clips and animal autopsy games.
Hybrid Hearts: Stem Cell Transplants 2.0
“Can we use stem cells to make a new heart/eye/lung/liver etc?”
This is the predictable and perennial question that comes up from at least one student when we are looking at stem cells, genetic engineering, cell differentiation and transplanting. Until now, the answer has (perhaps in an oversimplified way) been ‘no’.
We can use stem cell transplants to treat lymphoma. Recently a young woman had a trachea transplant based on stem cell technology. Skin grafts from a patient’s own cultured cells are also possible, as are stem cell-based bladders. However, these are all rather simple technologies.
To treat lymphoma, bone marrow cells are replaced, and are all the same. The trachea transplant was a pre-existing trachea simply coated in the patient’s stem cells to prevent immune rejection. Skin transplants are basically sheets of epidermis that cover a wound, yet do not have the intricate functions of original skin: temperature regulation, secretion, senses. The bladder is a bag.
The challenge with using stem cells to transplant a more complex organ, such as a heart, is that it is not a simple sheet made of one type of cell. It is complex 3D structure, with a range of cells performing specific tasks within the organ. These cells have differentiated to perform their functions: cardiomyocytes (beating cells), vascular endothelial cells (smooth internal surfaces) and smooth muscle cells (blood vessel walls).
How can we get the stem cells to become the right type of cell, in the right position?
The answer to this question could be the key to opening up new doors in the search for viable transplantable organs in medicine, and bears much in common with the trachea case. It also marks a return to form for the NewScientist YouTube channel, who have this short clip of the new hearts in action:
A full article to accompany the footage is here.
In a nutshell:
Decellularised pig heart: the scaffold (NewScientist)
1. Find a suitable transplant organ, such as a pig’s heart.
2. Strip of all cells and DNA, using a detergent. Only the collagen ‘scaffold’ remains, as in the image of the decellularised heart to the right.
3. Coat the scaffold with the recipient’s stem cells.
4. Ensure that the blood supply is adequate and will provide the right signals for differentiation.
What is amazing in this case is how the cells ‘knew’ what specialised cells to become. The leader of the research group, Dr. Doris Taylor, puts it down to the mechanical stimulus of the pressure of the blood in the vessels and chambers and chemical signals from growth factors and peptides that remained on the stripped heart structure.
They even went as far as replacing a healthy rat’s heart with one of these new hybrid hearts. The rat survived for the trial, but she says they need to focus on producing more muscular hearts in order to ensure long-term survival of transplant recipients.
Food for thought:
Read the whole article and some of the links within it. Discuss these questions:
1. What are the potential uses for this kind of transplant technology?
2. What are the current limitations of this method and how might they be overcome?
3. What are the ethical issues related to using hybrid (pig-human) organs in medical transplants? How would you feel if you were the patient?
4. Who are the various stakeholders in this technology and what are their viewpoints?
Useful Sources:
Dr Doris Taylor’s research page from the University of Minnesota
NewScientist Article: Hybrid hearts could solve transplant problem
BioAlive stem cells links and resources
Can stem cells repair a damaged heart? from the NIH
Research reveals how stem cells build a heart, from Harvard news.
Periodic Table for Biologists
Shortlink to this page: http://is.gd/iBiologyPTable
Click on this link to go to the periodic table page and download the A0 poster: http://is.gd/iBiologyPTable
Pandemic II: Educational Flash Game
Pandemic II: Spread the World
Thanks to the excellent NotExactlyRocketScience blog for posting the link to this game. Pandemic II is a complex flash game based on strategy, evolution (though more like design) and the spread of disease. The premise is simple – take a pathogen (bacteria, virus or parasite), and watch its spread across the globe. Along the way you can alter the pathogen to change its properties, making it more infectious, more lethal or less noticeable. The aim of the game is to wipe out the population of the world.
It is easy to save using Firefox add-ons.
Check out the game here: http://www.crazymonkeygames.com/Pandemic-2.html
And the tutorials here:
Is it better than the addictive Magic Pen Game or Foldit?
Have a go!
MOLO: The Molecular Logic Project
The Molecular Logic Project aims “to improve the ability of all students to understand fundamental biological phenomena in terms of the interactions of atoms and molecules”. They achieve this with an extensive database of online java-based simluations and models for students to use. The animations are simple, and there are a lot of activities to choose from. To make it work, you’ll need to install their software.
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Some highlights for IB Bio:
How do mutations affect protein folding?
How does gene mutation affect protein folding?
And loads more here: Biology, Molecular Biology (Chem of life), Physics/Chemistry.
Scientific American Frontiers
Thanks to bogstandardcomp from the TES Forums for this one.
Click Here
PBS have a series on their archives called Scientific American Frontiers. Although the last episode posted there was a couple of years ago, they have full episodes online and allow easy navigation within clips. There are also teaching resources and notes to go along with each one.
For some highlights have a look at:
– Make Up Your Mind (brain development and neuroscience)
– Hot Planet, Cold Comfort (climate change)
– Going Deep (ALVIN and deep-sea exploration)
– The Gene Hunters (Genetics and a few good resources)
NOAA Environmental Visualisation Library
Education Resources, Animations, Videos and Satellite Images
Awesome. NOAA (National Oceanographic and Atmospheric Administration) has revamped its Environmental visualisation libray – bringing new educational materials, visualisations, animations and resources to educators and the public. See the images of the 2008 hurricane season, animations of the ocean damage caused by humans or check out their library of satellite images.
They also have a YouTube channel where you can view and download some of their video resources. In relation to our upcoming Earth Day theme of “Reefs and Oceans“, here’s a clip about the effects of coral bleaching:
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Check out the NOAA image galleries too...
How to regrow a rainforest – Willie Smits on TED Talks
Willie and the orangs
My Grade 12 class have looked at this story before, and now we can hear about it from Willie Smitts, a primatologist and conservationist who has led a huge project to replant and revive a section on rainforest in Borneo. They have taken over 8,000 hectares of scorched and cleared land and are returning it to a habitat worthy of orang-utans and many more endangered species.
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Smits was featured in TED2009 and here he is with his story of how they regrew the rainforest.
The Kidney
Last topic for the HL Students!
The Kidney is great – it filters our blood, makes urine and ties together so many aspects of the course – cells, membrane transport, osmosis, chemistry of life, hormonal control. We can look at how it is similar to and different from the liver and how its structure reflects its function. I love the kidney.
Here’s the presentation, with some data-y questions at the end.
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More resources here:
Best kidney animation ever from biologymad.com
Quick guide to thekidney from kidneypatientguide.org.uk
Complete tutorial from Sumanas
Bilingual (Chinese and English) guide to the kidney, with rave tunes from hkedcity.net
More Loop of Henle action from the University of Colorado
Hormonal control of ADH from McGraw Hill
Diabetes recap from MedMovie
Kidney quiz from ZeroBio
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Want to see a kidney stone?
Find out more about kidney stones here.
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