Category Archives: Evolution (Core and Options)
Resources for Option D: Evolution
A huge thank-you to Jason de Nys of the Australian International School of Hong Kong for posting a link to his SlideShare page with presentations for Option D: Evolution. It is not an option that I have taught before, so there was a gap in the resources on this site.
One example is posted below, and the others are embedded on the appropriate pages, but please also visit Jason’s SlideShare page to see more of his work.
Thanks to Jason for sharing his work!
This presentation outlines a research project that we carried out a while back with a visiting geneticist. It uses authenttic research tools (and databases), and ties many elements of the course together – especially for HL students.
Jonathan Drori: The beautiful tricks of flowers
Here’s a nice calming video to watch as you wait for your IB results…
One for the HL students, to tie in with 9.3 Reproduction in Angiospermophytes. Gotta love nature!
Good luck and have a great summer.
Creation: Darwin Movie
Due for release this week, Paul Bettany stars as Charles Darwin in the biopic Creation. Based on Randal Keynes’ (Darwin’s great-great grandson) biography Annie’s Box, it promises to be a good movie and has received great reviews from the Toronto International Film Festival and the Guardian.
Here, the makers discuss the challenge of creating an exciting movie based on the life of a scientist, when the ins-and-outs of everyday science work can be pretty mundane. It looks as though they are focusing on the personal aspects of Darwin’s life and relationship with his wife as he works on the manuscript.
For more listening, the movie is discussed in this week’s Science Weekly Podcast, with discussion from Caspar Melville (with some questionable ideas*). Richard Dawkins also guests, to talk about his new book The Greatest Show on Earth.
Sadly, the movie has not yet only just been picked up for US distribution. I wonder if the title has something to do with that – perhaps Annie’s Box would have been easier to swallow? I also wonder if we’ll get to see it here in Indonesia.
* EDIT: It appears he was ‘conned’ by the AIDS-denialist ‘House of Numbers’ and explains here.
Posted in Evolution (Core and Options)
Tags: Darwin, Dawkins, Evolution (Core and Options), movies
Start with this reading on Evolution and Darwin: https://www.box.net/shared/6dx95t6ma6 and then watch this video of evolutionary researchers in action in Ecuador.
In the clip below, is Ross using the correct language when he describes the theory and evidence for evolution?
Here is the class presentation
And the Essential Biology notes can be found here: https://www.box.net/shared/550sxdbx82
There are many sources of interactives and animations on Evolution on the internet. Here are a few:
PBS Evolution has lots of high-quality activities and videos
BiologyInMotion has a very clear population evolution interactive
The Exploring Evolution weblab has examples of homologous structures and fossil evidence
MMHE has a pesticide resistance tutorial
And there are some good peppered moth simulations here and here
As always, sumanas has a great resource – this time on antibiotic resistance
And John Kyrk has a truly awesome timeline of the evolution of life
Attenborough on Darwin: The Tree Of Life
Dawkins Darwin Lectures from OU/BBC
And of course, all of Darwin’s works are available online from darwin-online.org
And here’s Dawkins on the evolution of the eye:
Grade 11 are starting out the course with a short “Nature of Biology” unit, made up of Statistical Analysis (and some practice with data), Classification, Evolution and a little introduction to ToK in Biology. Grade 12 are also looking at Classification at the moment, as part of the Ecology, Evolution and Conservation unit.
Here is the class presentation:
Download as pdf here: 5.5 Classification
Work through this Essential Biology 5.5 Classification as you go through the presentation.
There are some activities you can download here:
Invertebrate phyla cards and dichotomous key
Paired groups key-making activity: Spiders vs Beetles
And here are the Click4Biology notes
There is also a great Environmental Science course online here: The Habitable Planet
Posted in 09 Plant Science, Environments, Evolution (Core and Options)
Tags: classification, ib 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.
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.
Attenborough on Darwin: The Tree of Life
This is on my shopping list for sure – and one of those rare occasions I miss British TV. Attenborough kicks the Year of Darwin off with his new documentary, The Tree of Life. Sadly the BBC iPlayer thingy is only available in the UK, though I’m sure some will know how to fool it – if you hurry there are a few days left to download it!
Here’s the man himself (Attenborough, not Darwin – that would be cool) in an interview with Nature magazine:
And if you’re up for an interesting quick read, here are the Top Ten Myths of Darwin from The Rough Guide to Evolution blog.
Parthenogenesis – Virgin Births in Nature
Happy (belated) Christmas!
How do you really reproduce without sexual reproduction? Asexual reproduction, of course. Simple, really… but not for the females of some species.
There are loads of links in this post, so click on them to learn more.
Some plants, insects, shark and lizard species are known to reproduce by parthenogenesis – embryo development is carried out without fertilisation by a male -so called ‘virgin creations.’
Parthenogenesis can take a range of pathways :
- The egg can be fertilised by a polar body (a ‘leftover’ of egg production), making the chromosome number diploid and triggering embryo development. Here is a simple explanatory animation from amateurmicrography.net.
- Chromosomes in the egg can self-replicate, making up the diploid number and the embryo develops from there.
Other methods include suppression of male genotypes (technically still sexual reproduction?), or eggs cells dividing by meiosis.
The resulting offspring are going to be all the same gender. In some species, the XY system determines gender and parthenogenesis produces all females. In other, the ZW system dictates that they will all be male.
Parthenogenesis is a reproductive strategy that sacrifices the genetic variation (a driving force of evolution) of sexual reproduction for the simple ability to reproduce. Small invertebrates, such as aphids, can use it to produce large numbers of females very quickly.
Larger organisms, such as Komodo dragons (Indonesia link!), have been known to use parthenogenesis in the absence of males, producing an all-male clutch of eggs. It is thought that this might allow them to set up new populations on isolated islands, using just a single female. Here’s a quick video of a Komodo dragon parthenogen hatching:
Some interesting Komodo readers here from Richard Dawkins and Not Exactly Rocket Science.
Parthenogenesis has also been observed in captive sharks – the female had no access to males, yet gave birth to live young (though only one, where the normal litter would be larger). Genetic tests confirmed parthenogenesis, rather than the alternative hypothesis of superfecundation (storing sperm for a long period of time). Read the full paper here, and another on hammerheads here. BBC audio explanation here.
So can it work in us?
Let’s let House MD explain:
In short, no. Not naturally.
Generally, we use mitosis to replace and repair damaged cells and tissues and for growth and development – filling in the gaps with copied cells. Along the way, our cells differentiate to their function and we end up with a body full of specialised cells – each cell’s structure and biochemistry reflect its function.
We don’t use mitosis for reproduction, as it narrows genetic variation – one of the driving forces of evolution. Instead, when sperm and eggs are produced, meiosis is used – producing daughter cells with half a set of chromosomes. During meiosis, crossing over occurs, giving some recombinants – or ‘mixed up’ chromosomes – leading to some varation. The greatest variation comes from the process of sexual reproduction itself – the gametes – sperm and egg – meet in fertilisation, combining their chromosomes to make a new blastocyst, which becomes an embryo, then a fetus and out pops a baby.
All the offspring of organisms that reproduce sexually carry two copies of each chromosome – one from each parent – and each chromosome carries different alleles – ‘versions’ of each gene. This leads to a great deal of variation and this genetic diversity keeps the the population going.
What about uses in technology?
Funny you should ask that…
Induced parthenogenesis is being pursued as a method for obtaining embryonic stem cells. Read this New Scientist article to learn more.
The disgraced Korean scientist Hwang Woo-Suk, who shot to infamy after faking stem cell results, was actually and inadvertently pivotal in the use of parthenogenesis as a method to produce human embryonic stem cell lines:
Normally these parthenogenic embryos die after a few days, yet researchers are able to harvest them for stem cells for research. Ethically, these are considered engineered eggs, rather than human embryos. How do you feel about that?
Questions to think about:
1. How does parthenogenesis differ from binary fission in bacteria, or vegetative reproduction in some plants?
2. How do the XY and ZW gender systems work?
3. How does sexual reproduction lead to genetic variation?
4. What are the costs of parthenogenesis in terms of evolution or resistance to disease?
5. How would the genetic fingerprint of a parthenogen differ from its parent?
6. How would researchers use genetic fingerprinting to determine whether the offspring were parthenogens or were the product of sexual reproduction?
7. What are the ethical considerations of using parthenogenic human ambryonic stem cells?
Chapman et al. Parthenogenesis in a large-bodied requiem shark, the blacktip <i>Carcharhinus limbatus</i>. Journal of Fish Biology, 2008; 73 (6): 1473 DOI: 10.1111/j.1095-8649.2008.02018.x
Chapman et al. Virgin birth in a hammerhead sharkBiol Lett. 2007 August 22; 3(4): 425–427. Published online 2007 May 22. doi: 10.1098/rsbl.2007.0189.
Posted in 04 Genetics, DNA, Evolution (Core and Options), Marine Biology, New Scientist
Tags: 04 Genetics, cell differentiation, christmas, embryonic stem cells, Ethics, house, hwang woo-suk, komodo, Meiosis, parthenogenesis, polar bodies, richard dawkins, sharks, superfecundation, virgin births
Dawkins on Darwin & Channel 4’s ‘Genius of Darwin’
You can almost feel the Darwin fever as we near the 150th anniversary of the publishing of ‘On the Origin of Species‘. Channel 4 in the UK recently aired this special interview with Dawkisquawks talking about the life and work of Darwin. Their site is very good.
The whole lot has been posted to YouTube, but I doubt it will be there for long, so get on over and save it:
As Dawkins is wont to do, it is very long: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6.
Channel 4 is also running a new series called “The Genius of Darwin“, so keep an eye out for that:
Here is episode 1: Part 1, Part 2, Part 3, Part 4, Part 5. And here’s the whole thing on GoogleVideo
Here is episode 2: Part 1, Part 2, Part 3, Part 4, Part 5. It’s not on GoogleVideo yet.
Episode 3 should be up next week.
I recently made another post about ‘On the Origin…’, so head over there for more links. And if you feel like testing the strength of your bookshelf, I can recommend Dawkins’ newest book, The Oxford Book of Modern Science Writing.
Posted in 04 Genetics, DNA, Evidence, Evolution (Core and Options), Origins of Life
Posted in BBC, Evolution (Core and Options), Fun, Silly and Funny
Tags: flying penguins