Biopedia

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...

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.

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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.

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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...

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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...

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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...

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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...

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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...

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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.

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It's a well-known fact that humans have 23 pairs of chromosomes- 46 chromosomes in total. However, chimpanzees have 48 chromosomes, as do the other 'great apes'. Why is this? Well, it centres around human chromosome 2.

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