The process within a tumour can be evolutionary
The cells within it are not identical as a result of mutations and then selected.
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Mudface The web isn't callipygian, Thu 9 Sep 2021, 6:49,
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well, there's a lot of things that are analogous to evolution, even ideas
based on the profound "if something is able to increase itself, there will be more of it". Cancers tend to miss that final step, that of passing it's genes to a new organism, but I seem to recall tasmanian devil had facial tumours that scientist believed were communicable, so perhaps it could evolve
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cumquat may will not be commenting further on the allegations, Thu 9 Sep 2021, 10:41,
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The evolution of cancer within a body meets the definition of biological evolution
albeit on the level of populations of cells - being based on mutations in the DNA sequence and selective replication of individual cells with advantageous heritable mutations. The fate of those populations is extinction but then so is the fate of most species
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Mudface The web isn't callipygian, Thu 9 Sep 2021, 12:32,
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I think you'll find most definitions of evolution have it acting on the level of discrete organisms, and population of those organisms, rather than the body parts of multicellular animal
I know it's a semantic point, and I understand the way successful (in growing) tumours accumulate mutations seem highly analogous to the evolution of organisms, but it's not precisely the same thing. there is no inheritability because there is no path to the future. Its fate is tied to the organism it is part of, and its mutations will not be retained, whether good or bad. As I said, there are a lot of natural process that are analogous to evolution. If I hose gravel, and leave the heavier pebbles and wash away the sand, you could say the gravel evolved a heavier grained mix, in the same way cancer cells that have surface proteins that hide them from T-cell will survive and increase in ratio to those that don't. But the gravel and the cancer cells don't create new organisms that inherit those traits, so it's not strictly evolution. It's just similar to it. the odd tassie devil tumours may be an odd exception, and you could classify it a virus though I'm unclear of the mechanism of spread
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cumquat may will not be commenting further on the allegations, Thu 9 Sep 2021, 13:11,
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Gravel can't replicate, either sexually (judging by the lack of hardcore gravel porn) or asexually
The focus on organisms instead of any type of biological population is too narrow. I'm sure our microbiome undergoes evolution without leaving our bodies. Yes, a lot of semantics is involved to do with the dfinition of species and life (there are still those who argue that viruses are not living things).
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Mudface The web isn't callipygian, Thu 9 Sep 2021, 14:33,
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