Channel: This Place

Category: Education

Tags: environmentalthisthisplacechannelinclusive fitnesssustainabilitythisplacethis placeenvironmentthis place channelkin selectionhamilton's ruleplacehamilton's

Description: Why does life seem to be nicer to family? Would an offspring ever care for their parents? Inclusive Fitness, Hamilton's rule, Kin Selection SIDE NOTES / ADDITIONAL STUFF (sources for video in video credits) How Thale Cress recognizes family If you put a green filter beside them as they grow, they will bend their leaves away from the lifeless filter, like they do for family. Plants have proteins that detect light of certain wavelengths. It seems when light in those spectrums are blocked in the horizontal direction, like when there is a neighbor leaf there, they try to grow away from it. Plants from different families are going to have different genes, grow a bit differently, and their leaves will be at different heights and different angles. But closely related plants are going to be similar. They’ll have leaves that are at similar heights blocking the light in the horizontal direction for one another. That’s why they grow away from family and not strangers, their horizontal light profile, is going to be similar. When with strangers their leaves don’t match up so much. So they only bend away for family. At least that’s the idea. Thale Cress Leaf Bending: Is It Really for Family? They tested for that. Using a mutant that cannot bend their leaves, they put them in rows like mutant│wild type│mutant│wild type... The mutants were find on their own, produce the same number of seeds as wild type. In the row, the mutants produced more seeds than the wild type. In this context at least, the benefit seems to be for the other plant, not the bender. Plant altruism is a difficult thing though. There's only a finite amount of resources. Giving resources to a neighbor may be a 1:1 thing. Hard to detect. ncbi.nlm.nih.gov/pubmed/25264216 Family helping “strategies” This model describes where a gene’s protein CAN act, not necessarily where it will. What works for bees may not work for humans. The other proteins of that cell are a part of a gene’s environment. Bees and eusociality There’s a lot of discussion about how bees and other creatures evolved eusociality. Also Wikipedia page en.wikipedia.org/wiki/Eusociality#Evolution Article to get you started sciencealert.com/monogamous-queens-help-bees-cooperate it describes this paper ncbi.nlm.nih.gov/pubmed/21772268 Some Examples of How Cells Recognize Family The armpit effect. en.wikipedia.org/wiki/Armpit_effect In humans there’s what they call the Westermarck effect en.wikipedia.org/wiki/Westermarck_effect Ducks imprinting on their mother. en.wikipedia.org/wiki/Imprinting_(psychology)#Filial_imprinting When it goes wrong en.wikipedia.org/wiki/Brood_parasite Here’s a Sapolsky lecture. youtu.be/P388gUPSq_I?t=30m7s Starts at 30 minutes 7 seconds Why Aren’t We All Family? Really we’re asking “why don’t genes recognize when other cells have those genes?” For a gene to only help cells with those genes they have to have the effect where they are they have to have: - Some form of specific phenotypic marker, a pheromone, an appearance, a sound/call - Recognize that phenotypic marker - Only help cells with those genes. There are actually a couple specific examples, it’s called the Green beard effect en.wikipedia.org/wiki/Green-beard_effect Why isn’t it more common? Maybe it’s a little bit like asking “why don’t we all have 4 arms? Surely having more limbs would be beneficial” or “why don’t we have laser eyes to heat our food and melt our enemies”. But mutations are random and maybe 4 arms/green beards just weren’t a possibly part of our history. Maybe it’s because it’s working against the rest of the genome. There’s lots of genes that may not benefit from the green beard gene’s action. Mutations that shut off the green beard gene would make that cell reproduce more. Or maybe it’s common and it’s just difficult to detect. There are several papers that claim it’s relatively common and very important. It could that to our brains we just don’t think we can recognize specific genes. But that’s just because our altruistic genes are scattered over our 46 chromosomes, all with markers and recognizing parts and on average we just view our children as related. I don’t know for sure. Patreon patreon.com/user?u=849925