Biopedia

Biodiversity is often mentioned as one concept in popular culture. However, it can be split into different components depending on who you ask. Today, we’re going to explore two different ways of chopping biodiversity up.

Sources for this episode: 1) Author unknown, Wikipedia (date unknown), Gamma diversity (online) [Accessed 06/03/2021]. 2) Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (2nd edition). Sunderland: Sinauer Associates Ltd. 3) For a formula for Shannon’s index of biodiversity (which I’m going to try and discuss in a future episode), see: Fullick A., Locke, J. and Bircher, P. (2015), A Level Biology for OCR A. Oxford: Oxford University Press.

This week, we’re going to discuss sympatric speciation- the counterpart to allopatric speciation where no physical barrier is needed.

Sources for this episode: 1) Thain, M., and Hickman, M. (2014), The Penguin Dictionary of Biology, 11th edition. London: Penguin Publishing Group. 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) Author unknown, Understanding Evolution (berkeley.edu), Sympatric speciation (online) [Accessed 28/02/2021]. 4) Author unknown, National Geographic (date unknown), Speciation (online) [Accessed 28/02/2021].

Another bonus episode! This time, I’m going to focus on a less well-known story from the Darwin family. Specifically, let’s look at William Erasmus Darwin, the eldest child of the family. In 1877, Darwin published an article about his observations of William’s development.

Sources for this episode: 1) Author unknown, Wikipedia (date unknown), William Erasmus Darwin (online) [Accessed 25/03/2021]. 2) Darwin, C. R. (1877), A biographical sketch of an infant. Scientific American Supplement 86: 1373- 1374 (online, scan of the original available at JF Ptak Science Posts) [Accessed 25/03/2021]. 3) Author unknown, Wikipedia (date unknown), The Descent of Man (online) [Accessed 26/03/2021 for the date].

The Great Wall of China is one of the most imposing monuments humanity has ever created- after all, it’s not for nothing that the claim goes around that you can see it from space. However, it’s not just an effective barrier for humans. In fact, a 2003 study indicates that it’s causing speciation in the region…

Sources for this episode: 1) Su, H., Qu., L.-J., He, K., Zhang, Z., Wang, J., Chen, Z. and Gu, H. (2003), The Great Wall of China: a physical barrier to gene flow? Heredity 90: 212- 219. 2) The Editors, Encyclopaedia Britannica (2021), Great Wall of China (online) [Accessed 19/02/2021]. 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) Oltermann, P., et al., The Guardian/Observer (2010), The Ancient World (booklet series), Day 6: China. Associated with the British Museum.

We’re always taught that twins can either be identical or non-identical. But what is the basis for this? And is there ever a situation where twin type is not quite so binary?

Sources for this episode: 1) Davis, N., the Guardian (2019), Scientists stunned by discovery of ‘semi-identical’ twins (online) [Accessed 07/02/2021]. 2) Author unknown, BBC (2019), Semi-identical twins ‘identified for only the second time’ (online) [Accessed 07/02/2021]. 3) Author unknown, Wikipedia (date unknown), Twin (online) [Accessed 08/02/2021].

The term ‘Anthropocene’ (roughly translated as ‘Age of Man’) is a term that is sometimes thrown about on the radio or in science. But what is it exactly? As we’ll see today, the concept itself is relatively simpler, but nailing down the specifics is somewhat harder than it seems…

Sources for this episode: 1) Author unknown, Encyclopaedia Britannica (2020), Anthropocene Epoch (online) [Accessed 30/01/2021]. 2) Ashley, S., National Trust (date unknown), What is the Anthropocene? (online) [Accessed 30/01/2021]. 3) Author unknown, Wikipedia (date unknown), Chinese industralization (online) [Accessed 02/02/2021].

Science has to change with the evidence if it is to be trusted. One example of this comes with Dollo’s Law, named after the French Belgian biologist Louis Dollo. His original theory was that evolution would never, under any circumstances, retrace its path. However, as we’re going to see on the podcast today, that isn’t always the case. With new evidence came the need for a revamp of Dollo’s Law…

Sources for this episode: 1) Author unknown, Wikipedia (date unknown), Dollo’s Law of irreversibility (online) [Accessed 24/01/2021]. 2) Author unknown, Encyclopaedia Britannica (2018), Dollo’s Law (online) [Accessed 24/01/2021]. 3) Zimmer, C., National Geographic (2003), Recoil from Dollo’s Law (online) [Accessed 24/01/2021]. 4) The Editors, Encyclopaedia Britannica (2018), Peppered moth (online) [Accessed 27/01/2021]. NOTE: I think I get a bit mixed up in my speech at one point with the gastropod example. What I should have said is that shells started out coiled, uncoiled itself and then recoiled on at least two occasions.

In our third Rewind episode, I’m going to go back over the concept of dominant vs. recessive as a mechanism of genetic inheritance, which I’ve touched upon before but not really in any great detail.

Sources for this episode: 1) Fullick A., Locke, J. and Bircher, P. (2015), A Level Biology for OCR A. Oxford: Oxford University Press. 2) Thain, M., and Hickman, M. (2014), The Penguin Dictionary of Biology, 11th edition. London: Penguin Publishing Group. 3) Author unknown, Wikipedia (date unknown), Eye color (online) [Accessed 19/01/2021].

This episode is really going to do what it says on the tin- discuss the question of how many species there are in the world. This might seem a simple question, but a simple answer has eluded the scientific community for some years now. On the show today, I’m going to go through some of the methods past research has used to answer this question and what figures they came up with.

Sources for this episode: 1) Latty, T. and Lee, T., ‘Phys.org’ (2019), How many species on Earth? A simple question that’s hard to answer (online) [Accessed 16/01/2021]. 2) Mora, C., Tittensor, D. P., Adl, S., Simpson, A. G. B. and Worm, B. (2012), How Many Species Are There on Earth and in the Ocean? PLOS Biology 9(8): e1001127. A slight correction here- at one point I mention seven taxonomic levels, but I should have said six! The confusion came because ‘species’ was the seventh one.

Hi everyone, just a quick plug for my other show- After Alexander. This is a history podcast where we examine what happened between Alexander the Great’s death in 323 and the destruction of the last of the Hellenistic kingdoms by the Romans and Parthians. Specifically, it focuses on the Seleucid dynasty, descended from Seleucus I Nicator and eventually rulers over most of Alexander’s old empire in their glory days. If that sounds like it might be for you, feel free to head over and join us! Regular content resumes next week.