Tag Archives: radiation

Why Are There So Many Species?

The causes and ecological context of rapid morphological evolution in birds (2022) Crouch & Tobias, Ecology Letters, https://doi.org/10.1111/ele.13962

Image credit: Andrej Chudý , CC BY-NC-SA 2.0

The Crux

One of the biggest questions facing evolutionary ecologists is why some groups of organisms contain SO MANY species, while others are relatively sparse in comparison. We’ve discussed adaptive radiations on Ecology for the Masses before, which is when a burst of speciation occurs within a group, with new species adapting to fill new ecological niches. It could be that the reason for such uneven groups is that some clades, or related groups of organisms, are more prone to such adaptive radiations than others. If this is true, it would mean that such clades experience not only an increase in the number of lineages (species) that they contain, but also the number of traits they exhibit.

Increases in the speciation rate and trait evolution are the hallmarks of adaptive radiations, but they may not occur at the same time, which can lead to some different outcomes. Clades may diversify rapidly, without really evolving new traits, and this is known as a “non-adaptive radiation“. In contrast, a lineage may quickly evolve new traits without speciating, which is known as an “adaptive non-radiation“. To understand the causes and context of such evolutionary scenarios, today’s authors studied the history of bird evolution.

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Monitoring Freshwater Populations in the Chernobyl Exclusion Zone

Radiation can have extremely negative effects on an individual. But is it as easy to measure its effects on an entire population? (Image Credit: Hnapel, CC BY-SA 4.0, Image Cropped)

Variation in chronic radiation exposure does not drive life history divergence among Daphnia populations across the Chernobyl Exclusion Zone (2019) Goodman et al., Ecology and Evolution, DOI: 10.1002/ece3.4931

The Crux

As anyone who has recently watched HBO’s Chernobyl can tell you, large doses of radiation are capable of doing some pretty serious damage to an organism. But whilst examining the effect of radiation on an individual might be simple, monitoring those effects on a population can be difficult. Whilst radiation negatively effects fitness, it can also help individuals with higher radiation tolerance to reproduce and dominate within the population of a single species, making it difficult to monitor the exact effects of radiation on that population. If a population is filled with only those who were strong enough to survive, you don’t get an idea of the variation in the radiation’s effects.

This week’s researchers tried to break through that problem by looking at different populations of a water flea in Chernobyl’s Exclusion Zone (CEZ) – the area still barred from entry in eastern Europe.

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The Ecology of Godzilla

With the King of the Monsters back for his second turn in cinemas, we go through the big, the bad and the bigger problems that a creature of this size might have if it lived on Earth. Is feeding on radiation useful? Don’t be ridiculous.

The Ecology of Godzilla

3:24 – Cinematic History of Godzilla
13:54 – The Ecology of Godzilla
42:16 – Godzilla vs. No-one

The Physiology of Godzilla

01:41 – 2014 Godzilla Need-to-Know
07:08 – The Physiology of Godzilla
37:14 – Vet’s PSA (Adopting Foreign Pets)

Demonstrating Adaptive Evolution in Parasites

Host defense triggers rapid adaptive radiation in experimentally evolving parasites (2019) Bush et al., Evolution Letters, p. 1-9

The Crux

Adaptive radiation is a fascinating ecological concept, one with which anyone who knows the tale of Darwin’s finches will be familiar with. The basic premise is that an organism may evolve different forms (and ultimately become different species) in response to pressures exerted upon them.

But whilst this may have been observed in many vertebrates, it’s often overlooked in parasites, whereby host defenses can prompt divergence in parasite morphology. Today’s paper wanted to test the two basic concepts of evolution. 1) Can host defenses prompt physical changes in parasites? 2) Are these changes heritable?

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