Today’s topic is a return to the world of biochemistry with a discussion of Benedict’s test- used to test for reducing sugars and, with some modifications, non-reducing sugars. We won’t be discussing the precise methodology- and the subtle differences in methods/reagents between the sources I accessed- but we’ll discuss what exactly a reducing sugar is and introduce the topic of food tests along the way.
Sources for this episode: 1) Fullick A., Locke, J. and Bircher, P. (2015), A Level Biology for OCR A. Oxford: Oxford University Press. 2) Hine, R. (2019), A Dictionary of Biology (Oxford Quick Reference), 8th edition, Oxford, Oxford University Press. 3) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Penguin Books Ltd. 4) Author unknown, Wikipedia (date unknown), Benedict’s reagent (online) [Accessed 12/03 and 02/04/2022]. 5) Author unknown, Wikipedia (date unknown), Stanley Rossiter Benedict (online) [Accessed 12/03/2022].
As of February 12th 2022, it’s been 113 years since Charles Robert Darwin was born. As such, we’re back with another Darwin Day episode! This time around, we turn our attention to His Majesty’s Ship Beagle, which Darwin would famously sail on. However, most people probably don’t know a lot about the ship besides this fact. So, let’s explore the Beagle’s past and its possible connection to the present…
Sources for this episode: 1-2) Burchett, M. (1996), Oceanography and Marine Biology: Water Movements and Oceanic Circulation Patterns and Appendix III: Beaufort Wind Scale. In: Waller, G. (ed.), Dando, M. and Burchett, M. (principal contributors) (1996), SeaLife: A Complete Guide to the Marine Environment. Pica Press: Smithsonian Institution Press. 3) Darwin, C. R. (1945), The Voyage of the Beagle. The Temple Press Letchworth: J. M. Dent & Sons Ltd. 4) Dubowsky, N., and Dubowsky, S. M. (1994), The final mission of HMS Beagle: clarifying the historical record. BJHS 27: 105-111. 5) The Editors, Encyclopaedia Britannica (2014), Arafura Sea (online) [Accessed 09/02/2022]. 6) Goodin, M. M., Zaitlin, D., Naidu, R. A. and Lommel, S. A. (2008), Nicotiana benthamiana: Its History and Future as a Model for Plant–Pathogen Interactions. Molecular Plant-Microbe Interactions 21(8): 1015-1026. 7) Thomson, K. S., Encyclopaedia Britannica (2019), Beagle (online) [Accessed 03/02/2022]. 8) Author unknown, National Geographic (date unknown), HMS Beagle: Darwin’s trip around the World (online) [Accessed 05/02/2022]. 9) Author unknown, Royal Museums Greenwich (date unknown), HMS Beagle: Discover more about the ship that took Darwin around the world (online) [Accessed 03/02/2022]. 10) Author unknown, Wikipedia (date unknown), Beagle Channel (online) [Accessed 07/02/2022]. 11) Author unknown, Wikipedia (date unknown), Beagle Gulf (online) [Accessed 09/02/2022]. 12) Author unknown, Wikipedia (date unknown), HMS Beagle (online) [Accessed 03/02/2022]. 13) Author unknown, Wikipedia (date unknown), Robert FitzRoy (online) [Accessed 07/02/2022].
Darwin Day: Author unknown, Galapagos Conservation Trust (2015), Darwin Day Comic Strip (online) [Accessed 06/02/2022].
Natural selection is not just one phenomenon, but can be spliced into different types depending on what its action results in. Today’s episode will examine disruptive selection, stabilising selection and directional selection; what they are, what their effects on populations are and some examples we see in the natural world.
Sources for this episode: 1) Allaby, M., (2020), A Dictionary of Zoology (Oxford Quick Reference), 5th edition, Oxford, Oxford University Press. 2) Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (Second Edition). Sunderland, Massachusetts, Sinauer Associated Ltd 3) 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. 4) Hine, R. (2019), A Dictionary of Biology (Oxford Quick Reference), 8th edition, Oxford, Oxford University Press. 5) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Penguin Books Ltd.
Cultured cells are useful, but have their limitations. For instance, B cells- white blood cells which produce antibodies- have a limited lifespan in vitro, meaning their use for making antibodies commercially is limited. The solution to this is the topic of today’s episode: the hybridoma.
Sources for this episode: 1) Fullick, A. and Coates, A. (ed. Ryan, L.) (2016), GCSE AQA Biology (Third Edition). Oxford: Oxford University Press. 2) 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. 3) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Penguin Books Ltd.
Perhaps you’ve never thought much about bonsai trees. However, their existence does raise some biologically relevant questions. For instance, how is a bonsai tree created? Moreover, as we’ll see in today’s episode, they have also been considered as a tool in conservation…
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) The Editors, Encyclopaedia Britannica (2021), Bonsai (online) [Accessed 15/06/2021, 18/08/2021 and 19/08/2021]. 3) Joshi, A. R. and Joshi, K. (2009), Bonsai: A Technique for Conservation of Species, Bonsai and Conservation 1(1): 3-4. 4) Perrott, R., Synge, P. M. and Herklots, G. A. C., Encyclopaedia Britannica (2020), Gardening (online) [Accessed 18/08/2021]. 5) Wyman, D. (1954), Japanese dwarfed trees. Arnoldia 14(1): 1-7. 6) Author unknown, RHS Gardening (date unknown), Bonsai (online) [Accessed 15/06/2021 and 18/08/2021].
We’re going to explore a particular kind of hybridisation today- the kind that produces grolar bears. As the name might suggest, this refers to the offspring of a grizzly bear and a polar bear. Its existence- and that of cases like it- also allow us to put something called the biological species concept under scrutiny…
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) Callaway, E., New Scientist (2010), Neanderthal genome reveals interbreeding with humans (online) [Accessed 03/08/2021]. 3) 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. 4) 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. 5) Wei-Haas, M., National Geographic (2018), Ancient Girl’s Parents Were Two Different Human Species (online) [Accessed 03/08/2021]. 6) Author unknown, BBC Newsround (2021), Have you ever heard of a ‘pizzly’ bear? (online) [Accessed 02/08/2021]. 7) Author unknown, Understanding Evolution (berkeley.edu), (date unknown), Misconceptions about evolution (online) [Accessed 03/08/2021].8) Author unknown, WWF (date unknown), Top 10 facts about polar bears (online) [Accessed 03/08/2021].
Back in episode 49, I mentioned the Great American Interchange, which took place three million years ago when North America and South America collided and were connected by the isthmus of Panama. However, I largely glossed over it as it was only of tangential relevance to the topic of the Wallace Line. So, today, let’s correct that oversight and explore the Great American Interchange…
Sources for this episode: 1) Domingo, L., Tomassini, R. L., Montalvo, C. I., Sanz-Pérez, D. and Alberdi, M. T. (2020), The Great American Biotic Interchange revisited: a new perspective from the stable isotope record of Argentine Pampas fossil mammals, Scientific Reports 10(1): 1608. 2) Marshall, L. G., Webb, S. D., Sepkoski, J. J. and Raup, D. M. (1982), Mammalian Evolution and the Great American Interchange, Science 215(4538): 1351-1357. 3) Weir, J. T., Bermingham, E. and Schluter, D. (2009), The Great American Biotic Interchange in birds, Proceedings of the National Academy of Sciences 106(51): 21737-21742. 4) Author unknown, Wikipedia (date unknown), Great American Interchange (online) [Accessed 15/06/2021 and 13/08/2021]. 5) Author unknown, Wikipedia (date unknown), δ13C (online) [Accessed 10/08/2021]. 6) Author unknown, Wikipedia (date unknown), δ18O (online) [Accessed 10/08/2021].
Photosynthesis has proven a useful tool in life’s arsenal, but it isn’t perfect. This is because one of its enzymes- RuBisCo for short- is not equipped to deal with our oxygenated world and as such sometimes creates toxic by-products which the organism then has to expend energy to deal with. However, some plants have evolved strategies to deal with this issue. Instead of simply working with vanilla-flavoured C3 photosynthesis, they have switched to alternative strategies known as C4 or CAM photosynthesis…
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) 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. 3) Hirst, K. K., ThoughtCo (Updated 13/11/2019), Adaptations to Climate Change in C3, C4 and CAM Plants (online) [Accessed 27/07/2021]. 4) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Penguin Books Ltd.
Altruism- or actions by organisms which ultimately provide a benefit to other organisms- have been puzzling evolutionary scientists since Darwin’s time. As such, attempts have been made to explain how this phenomenon comes about. One of these explanations is the subject of today’s episode- kin selection and Hamilton’s rule. Now, I am not going to go into the arguments and evidence for and against it, which is probably a topic for future episodes. For now, it’s probably best to say that my previous studies on the topic have taught me that there is a tangible divide within biology on this topic…
Sources for this episode: 1) 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. 2) Dugatkin, L. A. (2007), Inclusive Fitness Theory from Darwin to Hamilton, Genetics 176(3): 1375- 1380. 3) The Editors, Encyclopaedia Britannica (2018), Kin selection (online) [Accessed 18/06/2021]. 4) Herron, J. C. and Freeman, S. (2015), Evolutionary Analysis (Fifth Edition, Global Edition). Harlow: Pearson Education Limited. 5) Oshaka, S., OUPblog (Oxford University Press, 2015), Kin selection, group selection and altruism: a controversy without end? (online) [Accessed 17/06/2021]. 6) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Penguin Books Ltd.
If Alfred Russell Wallace (1823- 1913) is thought of at all, he is an after-thought to his far more famous counterpart Charles Darwin and the theory of natural selection. However,he has also had an impact in other fields. Today, we’ll be exploring the Wallace Line and Wallace’s contribution to zoogeography.
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) Camerini, J. R., Encyclopaedia Britannica (2021), Alfred Russell Wallace (online) [Accessed 10/06/2021]. 3) The Editors, Encyclopaedia Britannica (2019), Wallace Line (online) [Accessed 10/06/2021]. 4) Marshall, M., New Scientist (2021), The other humans: The emerging story of the mysterious Denisovans (online) [Accessed 11/06/2021]. 5) Scoville, H., ThoughtCo (2020), What Is the Wallace Line? (online) [Accessed 10/06/2021]. 6) Smithsonian Tropical Research Institute, Phys (2016), Recent connection between North and South America reaffirmed (online) [Accessed 10/06/2021]. 7) Tang, C. M., Encyclopaedia Britannica (2018), Tethys Sea (online) [Accessed 11/06/2021]. 8) Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Penguin Books Ltd. 9) University of Adelaide, Phys (2013), Mysterious ancient human crossed Wallace’s Line (online) [Accessed 10/06/2021]. 10) Author unknown, Understanding Evolution (Berkeley, date unknown), Biogeography: Wallace and Wegener (online) [Accessed 11/06/2021]. 11) Author unknown, Wikipedia (date unknown), Wallacea (online) [Accessed 11/06/2021].
