Biopedia

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:

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:

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:

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 article from the journal 'Conservation Genetics' which concluded that the tuatara should probably be thought of as one species instead of two. I might come back to it in a future episode.

The paper in question is: Hay, J. M., Sarre, Stephen D., Lambert, D. M., Allendorf, F. W. and Daugherty, C. H. (2010), Genetic diversity and taxonomy: a reassessment of species designation in tuatara (Sphenodon: Reptilia), Conservation Genetics 11: 1063-1081.

Sources for this episode:

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:

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:

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:

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:

There are ways of working out biodiversity values, which we won't discuss in this episode. For a formula for the Shannon-Weiner index of biodiversity (which I'm going to try and discuss in a future episode), see: Thain, M. and Hickman, M. (2014), Dictionary of Biology (Eleventh Edition). London: Penguin Books Ltd. For Simpson's biodiversity index, 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:

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: