Why plants don’t die from cancer
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[0] https://www.economist.com/science-and-technology/2019/06/29/...
At a nuts and bolts level cell volume is less indicative of cancer as interfaces like skin, lungs, and intestines are vastly more likely to get cancer than most other tissues. Early cancers are often the result of mutations during growth from a single cell which is closer to log(volume) vs simple volume in terms of risks.
This might not seem like a major issue to us, but would be if trying to walk around by starlight at night.
Witness flatfish. We have good records for species to see that it took tenths of millions years for eyes to move 90 degrees on the head after fish ancestors decided to lay flat on the side on ocean floor.
It was good enough for the fish to see with single eye most of the time and evolution had little room for improvements since any wrong move with change in vision implied no vision and death.
To my naive understanding of evolution, it has little incentive to fix anything that breaks after reproduction age. So I would not expect evolution to catch on cancer ever.
I’d imagine it’s debatable whether elderly grandparents past reproductive years are helping their grandchildren be more reproductively successful. Possible, but not a forgone conclusion by any means.
http://en.wikipedia.org/wiki/Grandmother_hypothesis
> The grandmother hypothesis is a hypothesis to explain the existence of menopause in human life history by identifying the adaptive value of extended kin networking. It builds on the previously postulated "mother hypothesis" which states that as mothers age, the costs of reproducing become greater, and energy devoted to those activities would be better spent helping her offspring in their reproductive efforts. It suggests that by redirecting their energy onto those of their offspring, grandmothers can better ensure the survival of their genes through younger generations.
Again, reproduction is happening prior to any potential partner even knowing of a grandmother in many places in the animal kingdom. Even for humans actually.
So you're subscribing to the more adaptationalist line of reasoning for the existence of menopause. Which is fine. But you should concede that fact. Many others might subscribe to any of the other hypotheses for reproductive senescence. I subscribe to the artifactualist line of reasoning. ie - people just started living too long, and our bodies adapted for a 20-40 year life span. But there are numerous other hypotheses out there, many of them every bit as plausible as my artifactualist hypothesis. I only subscribe to the artifactualist hypothesis because it is the hypothesis most in line with the theory of evolution.
Edit: and https://www.cam.ac.uk/research/news/the-importance-of-grandm...
Edit2: and https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.1600...
Anecdotally, I can personally attest that having grandparents too far to help makes it a lot harder to raise our two young children - there will certainly not be a third one.
[0] https://www.cbc.ca/news/canada/montreal/grandmother-effect-1...
It’s an interesting hypothesis being studied, but not in any way cut or dry.
For more information on why group theory isn’t supported by the scientific community see the following:
https://en.m.wikipedia.org/wiki/Group_selection
https://en.m.wikipedia.org/wiki/Kin_selection
https://en.m.wikipedia.org/wiki/Evolutionarily_stable_strate...
Neither do most primates or lions. The elders just happen to be there. So we can't really even say if it's just more elders in the animal kingdom making themselves useful. Which, again, is happening after reproduction typically.
For something to have an effect on reproduction, I would think it would need to be part of the decision beforehand.
It seems absolutely not a coincidence that the much faster, by orders of magnitude, process of human history got set in motion at a time when grandpatenting, as an evolutionary concept, wasn't quite finished yet.
To a point. There is an inflection where the grandparent benefit becomes a burden on reproduction and survival. From a purely evolutionary perspective, this would probably occur where the presence of elderly people starts to impact the number of children born. We are seeing that today as many younger people are burdened with taking care of elderly relatives rather than raise children.
How many people of childbearing age have elderly parents?
By the time parents are elderly (60+, generally 70+ for needing substantial care) , children are already born.
Given how high the birth death rate is (for the mother), and presumably older bodies are weaker, there should be some evolutionary pressure for the menopause - simply said, as the P(death at childbirth) rises above some threshold, it's more beneficial for the mother to not be able get pregnant (and potentially die) again but instead continue nursing her existing children.
No such pressure exists for men because men have no cost of having extra offspring.
We have high cancer rates for children as well.
As I understand it, humans are quite unique in having menopause. Most species keep reproducing until they die, as do human males.
What if there were artificial evolutionary pressure? What if researchers start identifying specific mutations which are associated with cancer, then start editing them out of the DNA of unborn children?
But is this due to how we use our eyes? I always wondered how it could be that maybe half of everyone I knew in uni used glasses, when you'd think a 20-year old hunter-gatherer would need to be able to see stuff.
Is there research on this? Just wondering since I ended up having issues with nearsightedness in my early 20s but feel like I spent a lot more time outdoors as a child compared to children these days.
There are many possible factors, including genetics, light exposure, amount of time spent on closeup vs distance, and a shortage of vision therapy / behavioral optometry experts.
https://gettingstronger.org/2016/03/faq-for-vision-improveme...
I will chime in and say "not really". If a human makes it past say 10 years old (even really makes it past 2 years old), odds are they make it to 55-80 without modern medicine, civilization, etc.
The only reason life expediencies appear lower than 50 (all the way down to the 30s) in places and in eras is due to insane infant mortality driving the numbers down. The life expectancy of those who make it to 2 years old is dramatically higher than that general life expectancy number.
Violence (leading to either immediate death, or due to infection) and epidemics (e.g. HIV) are also very significant factors.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2672390/
Between 1850-1880, life expectancy in England was as long or longer than it is now. This predates antibiotics and nearly all vaccines, let alone what we today think of as advanced medical care.
Modern medicine and in many ways hygiene has removed many diseases like cholera, typhoid, smallpox, tuberculosis, and malaria from huge swaths of the global population. By one estimate Malaria alone has killed 50 Billion people throughout human history.
[1] https://www.nbcnews.com/health/health-care/why-don-t-elephan...
Those things are extremely dangerous, but we have not natural sensors to detect and avoid exposure to them.
I bought a geiger detector and it surprised me to find places with thousands of times more radiation than others.
Not able to find the link now as I am stuck somewhere.
Agrobacterium grows in the tumorous gall tissues in trees. They use these growths to multiply and trick the host to upregulate the nutrients for tumor and bacterial proliferation. These tissues then rot and bring the tree down with them.
Agrobacterium is frequently used in the lab to induce pluripotency or do gene injection.
The article is explaining why random DNA damage doesn't cause cancer in plants like it does in some animals.
While it's true that plants grow much differently than animal tissues, and that the rate of spontaneous cancer development is much greater in animals as a consequence, it is factually incorrect to say that plants don't die from cancers. We must also remember that a large number of human cancers are promoted by infectious agents.
https://old.reddit.com/r/askscience/comments/c6pjr3/why_do_p...
A note of caution, the link contains British humour and liberal use of sweary words.
https://www.reddit.com/r/CasualUK/comments/8gtw49/spwm_final...
Plants can stand better mutations than animals because they have a clonal structure and asexual reproduction. There are "bricks" in this structure called "leaves", "roots" or "stems between nodes", repeated again and again in the entire creature. Mutations lead often to stunted growing, thus health clones just overgrow and kill the damaged parts. They have an autoprune system also.
Would be fun to grow a patch of mutants.
> Plants, however, develop in a much more flexible and organic way. Because they can’t move, they have no choice but to adapt to the circumstances in which they find themselves. Rather than having a defined structure as an animal does, plants make it up as they go along.
This kind of fatality happens with humans, too, even if the cancer doesn't spread beyond the origin site.
So maybe it's the last point. For an animal you need a thorough layout, like for a cathedral (but, well there are also Gaudí's which aimed to be more "organic" - all these metaphors are so messy, maybe natural language is too organic)
> Harmful as it was, the nuclear accident was far less destructive to the local ecosystem than we were.
- most of plants nearby the nuclear facility are still radioactive right ?
- did animal leaving around also improved radiation resilience ?
Reality: Plants give off a pulse when attacked. Human ears don't "hear" it, so we don't count it as "screaming." They also communicate chemically with nearby plants when they get infested with hostile insects. You could say they put out the word and nearby plants of the same species act to protect themselves.
If the title were "Why cancer is nowhere near as fatal in plants as in humans," then your rebuttal would hold water. But that's not the title, so it has no bearing on my critique of the actual title.
> Why DNA mutations associated with abnormal division of cells in plants do not correlate with high fatality rates
This was surprising to me because a priori I didn't see why plants should cope with abnormal growth any better than humans. This made the question intriguing. The explanation that plant cells are designed so that dead cells can be quickly replaced and that cells are surrounded by rigid walls was gratifying in a way that "question is too anthropocentric" isn't.
Have a great day.