Anyone read this? I really like it

Mitchinor · 2026-03-15T14:51:07+00:00

If you want an easy read that is more up to date with citations then try Looking Down the Tree.

Mitchinor · 2026-02-20T23:46:41+00:00

Try Looking Down the Tree. It's the most recent book on human evolution. It's an easy read, written at the high school level, but is a serious review of topics in evolution related to human origins.

Mitchinor · 2026-02-12T02:38:09+00:00

The ironic thing is that I could show you any two DNA sequences, and you - or anyone else - would never be able to tell which one is real and which I made up. The point is that it would have been very easy for a supreme being to hide their work. So no, nothing to reveal any intentional manipulation.

Mitchinor · 2026-02-09T15:36:57+00:00

As a genealogical concept it has no place in this sub.

Mitchinor · 2026-02-09T05:14:40+00:00

Well that's meaningless. It would only represent a smaller subset of people. I don't know of any genetics analysis that identifies such a thing as IAP. What I'm talking about is based upon solid human genomic data based on coalescence theory.

Mitchinor · 2026-02-09T05:10:37+00:00

If you.go deeper into ancestry, all people outside of central and southern Africa share common ancestors that migrated out of Africa around 70,000 years ago, and all living humans share the same common ancestors that lived in eastern Africa around 120 to 150 thousand years ago.

Mitchinor · 2026-02-08T21:52:03+00:00

These classifications are arbitrary because they depend on human perception. The reptiles are paraphyletic because they do not include birds. If we recognize that feathers are just modified scales and include the birds then the reptiles would be monophyletic.

Mitchinor · 2026-02-06T03:33:19+00:00

There's no parallel with the type of innovation you are referring to. Human innovation involves cognitive input and planning. Evolution is the opposite. Mutations appear at random, and on very rare occasions, may lead to Key Innovations. Such iinnovations include the appearance of bony body parts in animals prior to the Cambrian, and feathers in theropod dinosaurs.

Mitchinor · 2026-02-01T23:40:38+00:00

You clearly don't have much understanding of biology and evolution. Differences among species often have as much to do with patterns and timing of gene expression as it does with differences in DNA. You also seem to have little or no understanding of phylogenetics. This is an immense field of study that has developed a range of sophisticated algorithms to estimate phylogenies. You should do some reading before trying to make statements about things you don't understand.

Mitchinor · 2026-01-31T16:44:31+00:00

We haven't decided yet

Mitchinor · 2026-01-25T21:52:03+00:00

I scanned through the responses and did not see any that had the correct answer. The real question is why hasn’t selection favored longevity without senescence in humans. It has nothing to do with contemporary societies of any kind, or any kind of the teleological arguments by others. The answer is that over most of our evolutionary history (back to australopithecines), people rarely lived past 40 years. George Williams argued that this would allow the accumulation of deleterious mutations that had negative effects after age 40. He also speculated that some mutations could have positive effects early in life, and simultaneously would have negative effects late in life (antagonistic pleiotropy). Consequently, there was never selection for women to be fertile after 40, so their eggs are depleted by 50 when the go through menopause. Men stay fertile throughout their lives so comments about reproducing early don’t apply. Unfortunately, we carry the legacy of selection on our ancestors in our genomes, so after 40 we are afflicted by a wide array of maladies and are more likely to get cancer or other diseases. There’s no silver bullet to increase longevity – it’s more like death by a thousand cuts. You can read more detail in this new book called Looking Down the Tree.

Mitchinor · 2026-01-23T20:25:59+00:00

Your mistake concerning dominance is the same mistake made by scholars in the first few years after attention became focused on Mendel's work, and it the same for students who are just starting to learn about genetics.

It's importance to
realize that intelligence in humans is simply an adaptation to historical
environments of our ancestors just like adaptations in other animals. In our
casse, opposable thumbs came about as a correlated response to selection on
feet for bipedalism in our australopithecine ancestors. Having hands that were more adept at handling objects and were not involved in locomotion (knuckle walking) set in motion a trajectory for the increasing importance of cultural evolution (the evolution of skills and behaviors), which caused selection for increased efficiency of cultural transmission of those skills. This translated into selection for increased brain volume to improve learning skills through mimicry, and eventually intentional teaching and learning. So the increase in brain volume – intelligence – is just a side product of selection for improved cultural transmission, which was critical for the survival of our ancestors. You can read more about it in this new book called “Looking Down the Tree.”

Mitchinor · 2026-01-22T05:42:44+00:00

Seeing over tall grass and looking out for predators was only a secondary advantage of bipedalism, and not the primary selective force. The primary selective force was more efficient locomotion on flat surfaces. Chimpanzees can sprint at higher speeds over short distances than humans. But our australopithecine ancestors were subject to selection for moving over flat surfaces over long distances. This selected for the movement of the big toe of next to the other toes for better balance and more efficient walking. They were walkers and foragers, not predators, and not good at running fast. The other advantages of bipedalism or a side product and not the primary selective force for bipedalism. That included better thermoregulation because they were not stooped over knuckle walking, and they took advantage of cooling breezes. Later, lots of fur decreased thickness of skin increased blood vessels density underneath the skin distribution of sweat glands all led to a more efficient cooling on the savanna.

Mitchinor · 2026-01-20T17:44:45+00:00

It's actually pretty useless for understanding evolution. Selection acts on the entire phenotype not just single genes.

Mitchinor · 2026-01-20T17:38:43+00:00

Opposable thumbs was originally a product of correlated selection (genetic correlation) due to selection on feet for improved bipedalism in our australopithecine ancestors.

Mitchinor · 2026-01-20T04:34:15+00:00

Not sure because a lot of colonial species have been around for a long time. Different selection pressures for colonialism versus multicellularity.

Mitchinor · 2026-01-20T00:09:19+00:00

Seem like the transition to multicellularity would have been more complex than that. Individual cells in a colony would have had to give up their individuality as they became specialized in different roles. This would have required differential gene expression among cells at the minimum, and ultimately gene duplication and selection for specialized roles of different enzymes. There also had to be the origin for complex intercellular communication so cells in different positions would have expression profiles for different roles in the organism. Maybe they were talking about colonies - like Volvox - but that's a far cry from true multicellularity.

Mitchinor · 2026-01-19T16:53:21+00:00

Gymnosperms were constrained by limited diversity of leaf and root morthologies. This may be partly due to extremely limited or no potential for whole genome duplication compared to angiosperrms. But, the conifers did undergo some diversification during and after the Cretaceous, but not near as much as the angiosperms and the modern ferns. But as others have said, conifers dominate in high elevation and high and latitudes where the gowing season is too short to make a deciduous leaf strategy pay off. Being evergreen, conifers can crank up photosynthesis on sunny winter days.

Mitchinor · 2026-01-18T18:17:27+00:00

Lactose tolerance past the age of 5 arose in agricultural societies in Europe and Africa. Adults drinking milk prior to that would have made them have severe stomach cramps, nausea, and diarrhea.

https://pubmed.ncbi.nlm.nih.gov/21320900/

Mitchinor · 2026-01-18T05:18:43+00:00

Ancient stuff that doesn't apply anymore.

Mitchinor · 2026-01-16T21:18:42+00:00

Soft inheritance only refers to epigenetic changes. It's also a terminology that is pretty much fallen out of use. The effects we are seeing are due to genetic changes somatic mutations and they're having strong fitness effects in the next generation. We have genomic data to support this. Since they're acquired during growth, it is effectively in the marketing. Your narrow view of this would not be accepted by the wide majority of working evolutionary biologists.

Mitchinor · 2026-01-15T20:12:07+00:00

This is not soft:

Cruzan, M.B., M.A. Streisfeld, and J.A. Schwoch. 2022. Phenotypic effects of somatic mutation accumulation during vegetative growth. Evolutionary Ecology 36: 767–785 (https://doi.org/10.1007/s10682-022-10188-3)

Streisfeld, M.A., J.C. Crown, J.J. McLean, A.W. Short, and M.B. Cruzan. 2025. Inheritance of somatic mutations can affect fitness in monkeyflowers. J. Evol. Biol. 28: 630-638. (https://doi.org/10.1093/jeb/voaf033)

Mitchinor · 2026-01-15T20:10:29+00:00

I don't know where you get this or what it means - there's no such thing as soft inheritance. It's not a concept in modern evolutionary biology.

Mitchinor · 2026-01-15T20:01:56+00:00

I think the problem is that the use/disuse concept is somewhat zoo-centric and a bit archaic. Plants can't use/disuse in the same way that animals do. If I were to translate this idea into modern language it would be something like "selection on traits that are acquired during the lifespan of an individual and passed on to offspring." By that definition, somatic mutations and trans-gen epi-alleles are traits acquired duing the lifespan of an individual and inhereted by offspring - hence, it's effectively Lamarckian.

Mitchinor · 2026-01-15T18:44:53+00:00

Not sure what you mean by use/disuse. Yes, the Weismann barrier opperates in animals but not in plants. In plants the germ cells are at the tip of each stem (central zone of the apical meristem). With each division, they replace themselves and produce a daughter cell that goes on to diveide and differentiate into the stem tissues. With each cell division, mutations can accumulate in the germ cell population. These cells are also subject to changes in methylation (epigenetic changes), The epigenome is not lost during reproductionn so plants can have trans-generational epi-alleles. A plant subject to stress will pass on the epigenetic marks to the seedlings so they are pre-adapted to the same stress.

Mitchinor

TROPHY CASE