Summary
Melvyn Bragg and guests discuss the relationship between parasites and hosts, where one species lives on or in another to the benefit of the parasite but at a cost to the host, potentially leading to disease or death of the host. Typical examples are mistletoe and trees, hookworms and vertebrates, cuckoos and other birds. In many cases the parasite species do so well in or on a particular host that they reproduce much faster and can adapt to changes more efficiently, and it is thought that almost half of all animal species have a parasitic stage in their lifetime. What techniques do hosts have to counter the parasites, and what impact do parasites have on the evolution of their hosts?
With
Steve Jones Emeritus Professor of Genetics at University College, London
Wendy Gibson Professor of Protozoology at the University of Bristol
and
Kayla King Associate Professor in the Department of Zoology at the University of Oxford
Producer: Simon Tillotson.
Transcript
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| 0:00.0 | This is the BBC. |
| 0:02.0 | Thanks for downloading this episode of In Our Time. |
| 0:05.0 | There's a reading list to go with it on our website. |
| 0:07.0 | And you can get news about our programs if you follow us on Twitter at BBC In Our Time. |
| 0:12.0 | I hope you enjoyed the programs. |
| 0:14.0 | Hello, all humans play host to countless parasites. |
| 0:18.0 | If not visibly on the surface, they're internally and between the cells or inside the cells themselves. |
| 0:23.0 | The parasites gain some advantage and we in turn are disadvantaged. |
| 0:27.0 | The food we eat nourishes us and we in turn nourish the organisms that depend on us. |
| 0:31.0 | Usually we don't notice but at worst we weaken, become diseased or die. |
| 0:36.0 | This relationship is found in all of the animals and plants and is as old as evolution. |
| 0:40.0 | The fittest who survive are those strong enough to reproduce despite their burden of parasites. |
| 0:45.0 | And this is all very fine to balance. |
| 0:47.0 | But if the parasites destroy their host, they may lose their home as well as their source of food. |
| 0:51.0 | Overall it's a very successful strategy for parasites. |
| 0:54.0 | And that is the most common life cycle of blebbing organisms. |
| 0:58.0 | We admit to discuss parasitism as Steve Jones, |
| 1:01.0 | emeritus professor of genetics at University College London, |
| 1:04.0 | Wendy Gibson, professor of proteology at the University of Bristol, |
| 1:08.0 | and Kayla King, associate professor in the Department of Zoology at the University of Oxford, |
| 1:13.0 | Steve Jones, can parasitism be defined or eat something that's hard to be done? |
| 1:18.0 | Well, I think you've defined it pretty well actually. |
... |
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