Biopedia

Biological warfare has been around for centuries. However, it itself isn't the topic of today's episode. Rather, today we're going to talk about experiments conducted with anthrax on Gruinard Island in the United Kingdom. Sources for this episode: Johnson, M. P., Pye, S. and Allcock, L. (2008), Dispersal mode and assessments of recovery on the shores of Gruinard, the 'anthrax islan...

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: Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (Second Edition). Sunderland, Massachusetts, Sinauer Associated Ltd. Hagen, J., Encyclopaedia Britannica...

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: Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (Second Edition). Sunderland, Massachusetts, Sinauer Associated Ltd. Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Pe...

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 Victo...

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: Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (Second Edition). Sunderland,...

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 occurrin...

Today, we're going to discuss classification. We're going to briefly skim over how people historically used to organise life, before the establishment of the prokaryote-eukaryote division which would stay in place until an American scientist called Carl Woese rocked the taxonomic boat... Sources for this episode: Craine, A. G., Encyclopaedia Britannica (2020), Carl Woese (online) [Accessed...

On the show today, we discuss the tuatara- two (or possibly only one) species of reptile which are the final representatives of an ancient lineage. I didn't really go into it in the main episode, but there appears to be some debate about whether or not the tuatara is one species or two. All the sources I'd used in this week's episode list two species, but I afterwards discovered an art...

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: 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- 12...

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: For an explanation of non-disjunction which I found helpful when I was at sixth form, see: Amoeba Sisters, YouTube (2017), Meiosis (Upd...

We often think about animals as an insular group. However, as with any genetic grouping, animals do have close relatives. On the show today, we discuss choanoflagellates- considered the closest relatives to animals today, and possibly a good candidate for what the common ancestor of all animals would have looked like. Sources for this episode: Campbell, N. A., Urry, L. A., Cain, M. L., Wasserman,...

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: Cain, M. L., Bowman, W. D. and Hacker, S. D. (2011), Ecology (2nd edition). Sunderland: Sinauer Associates Ltd. Author unknown, Wikipedia (date unkn...

This week, we're going to discuss sympatric speciation- the counterpart to allopatric speciation where no physical barrier is needed. Sources for this episode: 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. Thain, M., and Hickman, M. (2014), The P...

Bonus episode! Today, 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: Darwin, C. R. (1877), A biographical sketch of an infant. Scientific American Supplement 86: 1373- 1...

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: Campbell, N. A., Urry, L. A., Cain, M. L., Wasse...

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: Davis, N., the Guardian (2019), Scientists stunned by discovery of 'semi-identical' twins (online) [Accessed 07/02/2021]. Author unknown, BBC (2019), Semi-identical twins 'identified...

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: Ashley, S., National Trust (date unknown), What is the Anthropocene? (o...

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 Do...

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: Fullick A., Locke, J. and Bircher, P. (2015), A Level Biology for OCR A. Oxford: Oxford University Press. Thain, M., and Hickman, M. (2014), The Penguin Dictionary of...

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 th...

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...

The Central Indo-Pacific (or CIP if you're stuck for time) is a highly diverse region of the ocean. But how did it get to be this way? It's this question which is the topic for today's episode. Sources for this episode: Ivany, L. C., Patterson, W. P. and Lohmann, K. C. (2000), Cooler winters as a possible cause of mass extinctions at the Eocene/Oligocene boundary. Nature 407: 887- 890....

Building on our discussion of the Red Queen hypothesis last week, we're going to go through a theorem which is similarly chess-themed but goes against our hypothesis from episode 20. This theory holds that, rather than continual evolution being necessary for a species to survive, natural selection can sometimes allow genes to be lost from the gene pool. Sources for this episode: Allen, R. C.,...

This week, I'm going to discuss the Red Queen Hypothesis, which sounds intimidating but is actually rather straightforward. Not only is it an evolutionary theory, but it's also a reminder that biologists really like finding obscure reasons to name things... Sources for this episode: Scoville, H., ThoughtCo (updated 2019), What Is the Red Queen Hypothesis? (online) [Accessed 14/01/2021]. Th...

Happy Darwin Day! On the anniversary of Darwin’s birthday on 12th February 1809, I thought it would be fun to release a special episode covering some aspect of Darwin’s life or theories. Today, we’re going to discuss the health of Darwin’s children and of Darwin’s immediate family. Sources for this episode: Hayman, J., Álvarez, G., Ceballos, F. C. and Berra, T. M. (2017), The illnesses of Charles...