Creationists like to taut mitochondrial eve as a gotcha but never consider the mechanics of how lineages from a population of say 15k through a thousand generations actually behave.
I just spent some time doing just that with a bit of code where I simulate a starting population of 15000 females and tracking their individual lineages. Every generation each individual has a few children (amount per female is geometrically distributed to with chances adjusted keep total population stable (no bias), children per individual is hard-capped to 12) and each child is 50/50 male; (males are discarded).
From looking at the results there is a very rapid drop from the initial 15k lineages down to a few hundred lineages surviving after only a hundred generations. And after a thousand generations only a dozen lineages survive. You can find the code I used in this gist.github.
An example output of the amount of unique lineages per generation for the first 40 generations is
> 7608, 5023, 3801, 3040, 2557, 2190, 1909, 1671, 1480, 1353, > 1247, 1143, 1060, 991, 931, 888, 833, 788, 736, 701, > 667, 643, 616, 590, 563, 547, 520, 507, 492, 472, > 459, 447, 436, 425, 413, 402, 390, 379, 377, 368, > 358, 347, 342, 335, 328, 324, 317, 311, 303, 302,
After this there is a long tail that's slowly decreasing and ends up at 18 lineages surviving after a thousand generations. Keep in mind that the total population remains at around 15000 individuals.
If there was any bias added in favor of more prolific lineages then it would be reasonable to assume that only a single lineage would come out at the other end of only a thousand generations, even in a population that is growing.
URL: https://www.cell.com/cell/fulltext/S0092-8674(21)01269-1
DOI: https://doi.org/10.1016/j.cell.2021.10.021
Thanks in advance!
Here's my hypothetical situation. You have a tree population that is at risk of an oncoming bark beetle/fungus attack. Once the bark beetles arrive, they kill the trees at a consistent rate. These trees take around 100 years to go from sapling to mature reproductive adults, and both saplings and adults are at risk of predation and infection by bark beetles. You have a small population that you can introduce to the population that is homozygous dominant for a mendelian allele that creates resistance. Any hybrid or heterozygous individuals would also carry resistance. Is it possible to mathematically model the introduction of this new population into our old population?
Any papers you might suggest reading on this topic?
Hi all,
I've sat through about five Psych courses in the last year, and I've noticed that whenever the class discusses something that might be influenced by social settings, like gendered colour preferences or personality traits, inevitably someone mentions evolutionary advantage for the thing developing in hunter-gatherer societies.
I'm a humanities person, so maybe my questions are going to seem stupid, but I don't understand how something like colour preference could appear so quickly in the genes of a species. I thought humans started organizing into hunter-gatherer societies like 40,000-20,000 years ago, is that wrong?
Plus, I would assume that from the point where those societies arose onward, we would have to attribute a certain amount of psychological traits and changes to cultural influence. I don't understand how or where psychologists (or anthropologists, or historians, or anybody) found evidence for behaviours after hunting or gathering became things that apply globally to every regional group of homo sapiens on the planet outside of, like, cave paintings.
TBH I'm at a point where I don't even feel like evolutionary psych is legitimate. It seems equivalent to using Freudian psychoanalysis to prescribe anti-depressants. Can someone tell me where, if at all, the evidence comes from that supports evo-psych, or can you direct me to some readings so I can understand why it's so ubiquitously used in psych classrooms?
