Category: Podcast

Biological warfare has tragically been around for centuries, including the famous example of the Mongols catapulting heads over the walls of Kaffa (which I’m almost certainly oversimplifying here and won’t cover today). However, I want to talk today about experiments conducted with anthrax on Gruinard Island, right here in the UK.
Sources for this episode: 1) Author unknown, Wikipedia (date unknown), Gruinard Island (online) [Accessed 26/04/2021]. 2) Author unknown, Gov.uk (date unknown), The Truth About Porton Down (online) [Accessed 21/05/2021]. 3) Riedel, S. (2004), Biological warfare and bioterrorism: a historical warfare, BUMC Proceedings 17: 400-406. 4) Johnson, M. P., Pye, S. and Allcock, L. (2008), Dispersal mode and assessments of recovery on the shores of Gruinard, the ‘anthrax island’, Biodiversity Conservation 17: 721-732. 5) Madigan, M. T., Martinko, J. M., Dunlap, P. V. and Clark, D. P. (2009), Brock Biology of Microorganisms (12th Edition, International Edition), San Francisco: Pearson Benjamin Cummings Ltd. 6) Author unknown, BBC News (2001), Britain’s ‘Anthrax Island’ (online) [Accessed 21/05/2021].

Today is more of a follow-up episode building on episode 39. Specifically, we’re going to examine two different schools of thought about plant succession, known as the Gleasonian and Clementsian models…
Sources for this episode: 1) Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (Second Edition). Sunderland, Massachusetts, Sinauer Associated Ltd. 2) Hagen, J., Encyclopaedia Britannica (2020), Frederic Edward Clements (online) [Accessed 25/04/2021]. 3) Author unknown, Wikipedia (date unknown), Henry A. Gleason (botanist) (online) [Accessed 25/04/2021].

Our discussion this week is going to head back into ecology and focus on succession- a change in the species composition of a community across space or time.
Sources for this episode: 1) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition) (p.674). London: Penguin Books Ltd. 2) Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (Second Edition). Sunderland, Massachusetts, Sinauer Associated Ltd. 3) Thompson, J. N., Encyclopaedia Britannica (2018), Ecological succession (online) [Accessed 10/04/2021]. 4) Author unknown, Encyclopaedia.com (updated 2018), Plagioclimax (online) [Accessed 10/04/2021].

Haemophilia is a genetic condition which is characterised by one of the blood clotting factors, usually encoded for on the X chromosome, not being encoded for properly for various reasons- whether it’s a mobile genetic element inserting itself into the gene or a simple mutation. On the show today, we describe the cause and symptoms of haemophilia, as well as using the case study of Queen Victoria to show that new mutations are a surprisingly common root cause…
Sources for this episode: 1-2) Wikipedia entries for Factor VIII and Queen Victoria (online) [Accessed 08/04/2021]. 3) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Penguin Books Ltd. 4) Author unknown, The Haemophilia Society (date unknown), Bleeding Disorders > Haemophilia (online) [Accessed 08/04/2021]. 5) Francioli, L. C., et al. (2015), Genome-wide patterns and properties of de novo mutations in humans. Nature Genetics 47(7): 822- 826. 6) Mannucci, P. M. and Tuddenham, E. G. D. (2001), The Haemophilias- From Royal Genes to Gene Therapy. The New England Journal of Medicine 344(23): 1773- 1779.

We’re all familiar with populations, but what about a metapopulation? Put simply, these are populations of populations. Thanks to our sources and also my interpretation of the subject from back when I studied the concept, that’s the notion we’re going to unravel today…

Sources for this episode: 1) Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (Second Edition). Sunderland, Massachusetts, Sinauer Associated Ltd. 2) Thompson, J. N., Encyclopaedia Britannica (2016), Metapopulation (online) [Accessed 17/04/2021]. 3) Wu, J., Encyclopaedia Britannica (2019), Patch dynamics (online) [Accessed 18/04/2021]. 4) In this episode, I use an analogy from how I understood the concept from back when I was taught the concept at university, which I’ve signposted.

Back in the early 20th century, an English mathematician and a German scientist both independently came up with an equation to portray the frequency of different phenotypes in a hypothetical population. As we’ll see today, this equation rests on some pretty big assumptions which effectively exclude evolution. Why is this useful? Well, because we can use it to see if evolution might be occurring…

Sources for this episode: 1-2) Wikipedia articles for ‘Wilhelm Weinberg’ and ‘G. H. Hardy’. 3)TED-Ed, YouTube (2012), Five fingers of evolution- Paul Anderson (online) [Accessed 18/04/2021]. 4) Thain, M., and Hickman, M. (2014), The Penguin Dictionary of Biology, 11th edition. London: Penguin Publishing Group (p.329- 330). 5) Herron, J. C. and Freeman, S. (2015), Evolutionary Analysis (Fifth Edition, Global Edition). Harlow: Pearson Education Limited (p.257). 5) Chen, B., Cole, J. W. and Grond-Ginsbach, C. (2017), Departure from Hardy Weinberg Equilibrium and Genotyping Error. Frontiers in Genetics 8(167).

On the show today, we discuss the tuatara- two species of reptile which are the final representatives of an ancient lineage.

Sources for this episode: 1) Cooke, F., Dingle, H., Hutchinson, S., McKay, G., Schodde, R., Tait, N. and Vogt, R. (2008), The Encyclopedia of Animals: A Complete Visual Guide (p.370). Sydney: Weldon Owen Pty Ltd. 2) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition) (p.622). London: Penguin Books Ltd. 3) Author unknown, Wikipedia (date unknown), Rhynchocephalia (online) [Accessed 28/03/2021]. 4) Blythe, C. A., Encyclopaedia Britannica (2021), New Zealand (online) [Accessed 28/03/2021]. 5) Campbell, N. A., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V. and Reece, J. B. (2018), Biology: a global approach, 11th edition (Global Edition), Harlow, Pearson Education Limited: p.788- 789.

At A Level, we are taught that dominant: recessive traits are in a 3:1 ratio for any trait in which only one gene encodes for it. However, it’s not always that simple. Enter lethal alleles…

Sources for this episode: 1) Author unknown, Wikipedia (date unknown), Lethal allele (online) [Accessed 26/03/2021]. 2) Author unknown, Wikipedia (date unknown), Manx cat (online) [Accessed 27/03/2021]. 3) Gao, Z., Waggoner, D., Stephens, M., Ober, C. and Przeworski, M. (2015), An Estimate of the Average Number of Recessive Lethal Mutations Carried by Humans. Genetics 199: 1243- 1254. 4) Roos, R. A. C. (2010), Huntingdon’s disease: a clinical review. Orphanet Journal of Rare Diseases 2010 5:40. 5) For an example of the deleterious effects of inbreeding as discussed in today’s episode, see the Wikipedia or Encyclopaedia Britannica pages on Charles II of Spain. I might come back to him and his ailments in a separate episode, but until then he will also serve as a good example.

Usually, we get two copies of each chromosome. However, the finely tuned process of meiosis and fertilisation can go awry such that a new zygote ends up with three copies. Depending on the chromosome, this can have serious consequences…

Sources for this episode: 1) For an explanation of non-disjunction which I found helpful when I was at sixth form, see: Amoeba Sisters, YouTube (2017), Meiosis (Updated) (online) [Accessed 25/03/2021]. 2) NHS website, Edwards’ syndrome (trisomy 18) (online) [Accessed 25/03/2021]. 3) Xu, X., Zhang, X., Han, J.-W., Adamu, Y. and Zhang, B. (2020), Potential Increased Risk of Trisomy 18 Observed After a Fertilizer Warehouse Fire in Brazos County and TX. International Journal of Environmental Research and Public Health 17: 2561- 2571.