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5

How is convergent evolution distinguished from homologies in anatomy?

I know that in many cases, convergent evolution commonly occurs in anatomical traits, making phylogenies based off of morphology less reliable than molecular ones. Why then are phylogenies from fossil organisms often constructed using anatomical traits if they are really that unreliable and how would they distinguish between homologies and convergence given this? Are some traits just more likely to be convergent than others?

9 Comments
2023/09/25
04:37 UTC

4

tetrapod evolution?

did land vertebrates evolve from tiktaalik, acanthostega or ichtyostega? if the answer is tiktaalik, then what are the descendants of the latter two? im very confused about the evolution of tetrapods from lobe finned fish and then from tetrapods to all the land vertebrates :(

3 Comments
2023/09/24
22:21 UTC

9

How does game theory apply to animal behaviour, without the assumption of rational agency?

Classical game theory rests upon the assumption that agents are rational, meaning they are capable of understanding the consequences of their actions, and that they respond to the incentives in their environment.

But non-human animals don’t have anywhere near the level of reasoning abilities as humans do.

Even if a chimpanzee were to rape a young woman, they’re not going to be thrown in prison, as we understand that the ape can’t grasp human social rules or understand the long-term consequences of their behaviour.

When we have an environment of irrational agents, or agents with limited rationality, that definitely changes the outcomes compared to an environment of highly rational agents.

12 Comments
2023/09/24
04:02 UTC

0

Can you force evolution on a single human being . Read the description

Ok this might be a really dumb question , but I read this in a fiction story , they had some kind of death match among several groups , winner of each group were grouped again and were thrown into a death match , and the same process was repeated each time the winner of the group being grouped again with other winners to fight to the death . Now in that story the last man standing had evolved into a person who had inhuman strength . Could this be done in real life to an extent , like would this actually work ?

Edit - also if not evolution, what would be the result of this experiment, would the last person standing really have gained any extra strength?

17 Comments
2023/09/24
00:17 UTC

32

An "intellectual" Twitter user tweeted a claim about the DNA ancestry of Sub-Saharan Africans, can someone debunk this?

While browsing Twitter this morning I ran into a post about a dark skinned woman having a public freakout. Scrolling the comments, a Twitter "Intellectual" posted a picture that read the following:

"Present-day sub-Saharan Africans trace up to 19% of their genetic ancestry to an extinct archaic hominid species (Homo erectus or Homo habilis) that is NOT found in the DNA of present-day Asians or Caucasians".

My guess was this guy was using the fact that she had African ancestry to suggest she was "animalistic" in her behavior (even though she was clearly mentally ill) and used this claim as "evidence".

I never once heard of this claim until today and I couldn't find anything about it. I've heard of some humans from Europe having a small percentage of Neanderthal DNA, but 19%? This claim looks like total B.S and I'm 99% sure it is.

Can anyone debunk this for me or tell me more information about this so I can see the validity of what this "intellectual" is saying and I can use it as an argument against him.

Edit: I just need some kind of scientific evidence that proves that he isn't as smart as he thinks he is and that his claim that Africans are somewhat less human than other races is completely fraudulent information. I want an argument that shows that this isn't the "gotcha moment" he thinks it is.

60 Comments
2023/09/23
16:13 UTC

0

Human evolution

Considering evolution, what do you think humans kind will become or turn into next?

6 Comments
2023/09/23
13:25 UTC

9

What's the origin of sexual dimorphism among animal species?

a

11 Comments
2023/09/23
01:08 UTC

4

Help with identifying a term or concept within evolution

A few years ago I watched a nature documentary, I believe it might’ve been from BBC. The part that stuck out to me was when the narrator said something along the lines of “when there is lots of competition/all the roles have been filled in the food chain. There is a little Evolution, taking place. When there is a little competition and plenty of open spaces in the food chain, then you will see a lot of evolution.”

Has anyone heard a saying similar to this, or know the term/concept this is called?

8 Comments
2023/09/22
22:54 UTC

77

At what age were you first exposed to the idea of "evolution"?

This is a question from a previous post about someone asking if they have the prerequisites to learn about evolution or if it is just for bio/chem geniuses.

And I started remembering that I was reading books (aimed at younger ages) about evolution from elementary or early middle school.

Is it more normal for people to be thinking about changes in species (without necessarily getting into the hardcore genetics) at a younger age, or do most people learn about the broad concepts in college or older?

167 Comments
2023/09/22
19:14 UTC

9

Can I learn about evolution as a law student with NO biology/chemistry background? Are you required to be a biology/chemistry genius in order to learn more about the theory of evolution?

Can I learn about evolution as a law student with NO biology/chemistry background? Are you required to be a biology/chemistry genius in order to learn more about the theory of evolution?

37 Comments
2023/09/22
18:04 UTC

2

NK Model

Hi, is anyone familiar with the NK evolution model? In the 3D image on that wikipedia page, what do the two horizontal axes represent?

3 Comments
2023/09/22
16:13 UTC

9

The Golden ratio

The golden ratio, also called the fibonacci sequence is almost everywhere in nature. It is in galaxies, weather patterns, sea shells, and animals. As this article states, it's also featured in a bee's family line.

https://www.mathnasium.com/blog/14-interesting-examples-of-the-golden-ratio-in-nature#:~:text=Today%2C%20its%20emergent%20patterns%20and,it's%20certainly%20a%20major%20player.

Why did everything develop like this? correction (almost everything)

20 Comments
2023/09/22
11:26 UTC

7

Does narrowing environmental variation increase heritability?

Hi everyone!

I have a question regarding the notion of heritability. I've heard the point made that , when measuring a trait in a population, if the range of environmental variation is narrowed, heritability will increase.

I have tried to reaserch that question but came up with conflicting information.

https://www.sciencedirect.com/topics/medicine-and-dentistry/environmental-factor :

"The total variance in phenotypes (VP) in a population can be decomposed to a genetic component (VG) and an environmental component (VE): that is, VP = VG + VE. Thus, the heritability is the proportion of the total variance represented by the genetic variance: (VG/VP)"

"Furthermore, heritability depends entirely on the set of environments in which it is measured. If one changes the environment, heritability may change in unpredictable ways, both because the phenotypic variance depends on the variance in environmental effects and because genotypic effects may depend on the environment (GxE). One cannot say on the basis of heritability whether or not a trait will change in response to an environmental manipulation."

To me it makes sense according the formula Heritability = Vg/Vp with Vp = Vg + Ve , that if you reduce variation due to environnement (Ve), two things have follow: -> Total variance Vp will decrease -> Heritability will increase

Is that not equivalent to say that reducing environmental variation increase heritability? For what it's worth, ChatGPT agrees with my logic.

Thanks for you're attention !

10 Comments
2023/09/21
14:37 UTC

2

Important mediators in cell-cell communication and paternal epigenetic inheritance: Extracellular Vesicles are taken up by somatic cells and germ cells, including the sperm. Carry various cargos, including genomic DNA, mRNA, miRNA, and proteins.

In an earlier topic for how Darwinism is changing medicine following the clues led to Extracellular Vesicles as in the following 2022 research paper, from which three key sentences of text were used to form the above topic title:

The repertoire of testicular extracellular vesicle cargoes and their involvement in inter-compartmental communication associated with spermatogenesis

References this 2016 paper:

Epigenetic inheritance of acquired traits through sperm RNAs and sperm RNA modifications

After reaching this I knew I went from devo to evo:

We suggest that an integrative molecular approach, including a comparative phylogenetic analysis of the molecules (e.g., proteins and nucleic acids) derived from the EVs of interacting organisms (and their closely-related species) in the malaria system will prove useful for understanding interkingdom communication. Such analyses will also shed light on the evolution and persistence of host, parasite and vector interactions, with implications for the control of vector borne infectious diseases.

Extracellular Vesicles Could Carry an Evolutionary Footprint in Interkingdom Communication

Earlier studies like this below found little DNA change and mostly epigenetic, in Darwin's finches:

The Galápagos Islands only recently underwent urbanization, leading the researchers to wonder how organisms there are coping with speedy environmental change. By examining populations of two species of Darwin's finches, researchers from Washington State University and the University of Utah uncovered morphological differences between urban and rural populations of Geospiza fortis as well as epigenetic differences between urban and rural populations of G. fortis and G. fuliginosa. However, as they reported in BMC Evolutionary Biology last night, they found little genetic variation.

https://www.genomeweb.com/sequencing/epigenetic-differences-found-between-urban-rural-populations-darwins-finches

Extracellular vesicles and epigenetics are going to be an extreme modeling challenge, but now more than ever it goes with the territory of evolutionary biology.

For how epigenetics influences morphology the best I know of is from cognitive biology. This 15.5 minute video covers the basics:

Where is Anatomy Encoded in Living Systems? | Michael Levin

Question now is what all the above looks like systematically, in a complete as possible model of even a simple as possible one strand or plasmid cell.

There may already be a research paper, or even experimental model with Python code, but I know of none.

Where it's close enough in suitable environment it should be able to sustain itself then (hardware speed willing) evolve chromosomes and multicellularity on its own. Environmentally coaxing would speed up change. Extracellular vesicles like ours possibly emergent from simplest cell to cell exchange/communication. Maybe you know of a possible precursor?

Even though the software can become mind boggling to imagine I picture RNA and/or DNA bases stored at (when uncoiled) 3D locations in a molecular dynamics generated environment where all DNA products are considered thermal energy powered units interacting with each other to self-assemble and self-disassemble on their own, in a given molecular condition. Nearby molecular forces sum to apply forward or reverse thrust to each in a given direction as in a motor. Behavior of its smallest parts and decay products would be one unit, not have to compute atom by atom and be too incredibly slow to be useful with even a supercomputer.

There are tricks from machine intelligence that allow the epigenetic control level to be represented as confidence level in the DNA being useful at the time, which is modulated up or down by homeostasis, and when modulated down enough should enter a hypermutation state or otherwise DNA region easily changed, a guess. It's then trial and error self-learning, and in at least cognitive biology would qualify as "intelligent" while homeostasis alone would not. For unknown details it's one of the clues I'm going on where it's what the system needs, to at the molecular level on up go from unintelligent as an old-fashioned heat thermostat, to the entity controlling its setting to stay warm who used trial and error learning to invent them.

It can at first maybe seem like a complication but with the requirements of a homeostasis/confidence system controlling an addressable/changeable memory it's only what happens when a DNA region fails. In robotics an error, or unsuccessful as when a motor stall when it hits a wall. For immune cells hypermutation would be in response to sensing the failure to destroy an invader. Sensory controls what the memory does, otherwise it's unused or out of control region. Error conditions like these are where it helps to assume there will more likely be DNA level change, of one kind or another including the region being removed, moved, inverted, etc.. Morphological control of cells, in turn emergent multicellularity, is then a trial and error fast learner.

Where the cells are close enough in morphological capabilities multicellular trial and error learning to navigate the cell colony around in search of what they via blood stream want delivered for nutrients, is expected to happen on its own, by being an emergent property caused by (surrounding nucleus) cells having a level/layer for cell migration trial and error learning. Connecting together in a useful way becomes more like intuitive, as though they sense they connected into their version of an internet.

An epigenetic layer is absolutely needed to "address" and control the DNA memory system. A prediction not surprise. In turn this new information makes it easier to explain how epigenetics relates to a most basic machine intelligence and evolutionary biology. Can start with most simple genetic system possible, and should only have to accurately model the (inside a nucleus) genetics for all the rest including morphology to emerge on its own. Or at least that's what I predict.

I'm not sure whether everyone into evolutionary biology already assumed most of this, but after following the evidence to wherever it leads led me there. Your ideas where to go from here are welcomed.

And thanks for reading this far! I was hoping to make this the only thing you need, to maybe make the thinking work in your evolutionary algorithm models. Please let me know if it does.

2 Comments
2023/09/21
02:53 UTC

4

Why are human instincts so ineffective reactions in real world dangerous situations?

Prey will run fast. Predators may go on offensive. Some will utilize defenses like shells, quills, or venom. Some will fly, run up a tree, or dive into water. Even stealthier animals will utilize their environment to hide or rely on camouflage. Though not perfect all these strategies are all effective.

Why are humans so much more prone to ineffective survival strategies in dangerous situations. A young male may escalate the situation when he feels his ego is threatened. A mother might shield her child from an attacker and very likely get them both killed anyway. Some people freeze up or get mentally "tilted," causing them to make irrational decisions. All these being based on ineffective instincts for the situation. The best actions to survive are learned from cultures that have specifically had to develop strategies to cope with dangerous situations Military, LE, Pilots, etc. Everyone has to go out of their way to learn how to deal with survival scenarios. A lion can learn everything it needs to know from direct experience like observing older lions, playing, and relying on its' instinct. An average person in modern society put in a life or death situation would not be effective at all. Perhaps a hunter gatherer would fair far better.

Is it a matter that human life has much more complex and novel dangers compared to the rest of the animal kingdom?

Am I missing something about animals being killed by cars, traps, or hunting strategies not being equivalent due to the intelligence gap (even though a lot of humans have been killed by these same things.)

Why do we seem so ineffective by default in high risk scenarios?

63 Comments
2023/09/20
18:52 UTC

2

Rodents.

It is said that we may have evolved from rodent like creatures before the primates. If the 6th mass extinction wipes us out and some rats survive. What are the chances they will evolve back to humans? Just some shower thoughts.

23 Comments
2023/09/20
16:11 UTC

22

What's the degree of sociality in humans compared to the rest of the animal kingdom? Is it really a lot more complex?

I know that, for example, in the times of the hunter-gatherers it was more akin to that of other primates, but since the advent of agriculture, a lot has changed.

14 Comments
2023/09/20
13:03 UTC

8

Kin Selection

I understand that there are genes that promote altruistic behavior for their own survival (selfish) through the selection of genetic relatedness, but how does that work on a practical level? I've been reading about it but haven't really grasped the meaning of it entirely.

The closer family members are to our inner circle the more we tend to feel a sense of protection even at the cost of our life. Now, that happens because we grow up with them and they make us feel safe, we know we can count on them, and in turn, they surely can count on us. That isn't linked to actual genetic relatedness because if we were to have brothers or sisters that we didn't know about and randomly encountered in the street, we would have to "feel" a connection just by crossing our eyes.

Is it an old instinct that was applicable when we lived in small villages where certainly most people living there would be relatives? Does it misfire now? Is that why we feel empathy for people we don't know? Is it irrelevant to our current evolution?

12 Comments
2023/09/20
00:37 UTC

36

Why Bats?

its been exactly a decade since i was told that bats are the only flying mammal so now i am asking you all, why? why is it that bats are the only flying mammalian and how the hell did it happen?

43 Comments
2023/09/19
23:32 UTC

15

Perry?! the platypus

What did platypuses evolve from, When did it evolve, and are there any animals similarly weird and out of place?

22 Comments
2023/09/19
17:29 UTC

3

cichlids

tell me somethings you know about the fascinating evolution of cichlids 😎 wpuld love to hear

6 Comments
2023/09/19
02:15 UTC

10

Recommendations for books on bird evolution?

Would love to learn more about how birds diverged from non-avian dinosaurs and diversified. Would be great if it talked about both modern and extinct species :)

6 Comments
2023/09/18
20:33 UTC

8

Are there other candidates for the base of life other than carbon and silicon?

I mean complicated life, not just blobs or single celled organisms

11 Comments
2023/09/18
20:25 UTC

10

Gene loss

Is gene loss more prevalent than gene gain throughout the spectrum of multicellular evolution? For volvocine algae, this seems to be the trend. How do other model organisms fare in terms of both co-option and gene loss?

6 Comments
2023/09/18
03:39 UTC

0

Do phenotypical traits evolve faster than genotypical's?

Hello everyone. Human evolution junkie here.

I have this question, I know evolution is a long process of millions years of small changes, specifically referring to human evolution, we know our brains evolved over the course of millions of years and obviously it wasn't an overnight change, same with the loss of a high amount of body hair and bippedalism. So it seems evolutionary changes of "organs" happen at a slower scale, like to this date we haven't get rid of apendix of wisdoom teeth, or that it'd take millions of years for us to naturally develop an organ that allows us to..I don't know, help the lungs to filter the air's pollution.

But our phenotypes seem to change faster to adapt to the environment, blue eyes, for example, appeared 6,000 - 10,000 years ago, which is relatively "recent" in terms of evolution, same with white skin as it appeared around 40.000 years ago when early humans moved to the Middle East/Europe, and the same goes with blonde hair and other skin tones, hair texture also changes to adapt to the environment, even our noses, it seems.

Do our physical traits evolve faster to adapt and guarantee a better adaptation to the environment than our genotypes?

Thank you!

23 Comments
2023/09/17
18:26 UTC

5

What is the name of the branch of knowledge for…?

I remember reading about little biology facts that animals use for homeostasis and biological functions. Some examples are endothermia from blood cell friction, osmosis, goosebumps, teeth chattering to produce heat, melanin absorbing light, and fever immune response to an infection.

3 Comments
2023/09/17
02:03 UTC

14

Homology of differentiated sex

So, here's a question I've wondered about for a while, but haven't quite known how to get an answer.

As a preface, I'm aware that sex is a complicated matter in biology and even in cases where it's conventionally thought of as a binary, it can be closer to reality to think of it as a bimodal distribution of various traits. And of course many species are naturally hermaphroditic, change sex during their life cycle, and all sorts of other weird and wonderful things. This question is keeping that all in mind.

So, basically to what extent is biological sex homologous across life, and what is convergent evolution? Plants are said to be "male and female" are those the same "male and female" conditions that us mammals have, or are they merely convergent and named the same? I know even among tatrapods the mechanism of sexual differentiation (chromosomes, etc) can vary wildly. Is it still homologous?

Basically at what point or points did "male and female" sexes form, and are there multiple or one single lineage of organisms with that trait?

Relatedly, I'm curious of the homology of sex organs across taxa. I presume there's not much if any taxonomy between the "penises" of mammals and insects, though admittedly I know nothing of what the genitals of our last common ancestor would be like, but I do wonder if the hemipenes of reptiles are homologous or convergent to the mammalian penis.Beyond of course stemming ultimately from the cloacae common acrross tetrapoda (and likely further, but admittedly I'm just a lot more familiar with tetrapods.

6 Comments
2023/09/16
12:10 UTC

1

It seems all depictions of early humans show them with Caucasian-colored skin. Do we know that?

Or is their actual skin color unknown and merely imagined as white? (Edited.)

35 Comments
2023/09/16
02:32 UTC

2

Could humans and Cats be considered to have evolved as symbiotic species? Why or why not? Why would Cats and humans have chosen to become symbiotic?

Could humans and Cats be considered to have evolved as symbiotic species? Why or why not? Why would Cats and humans have chosen to become symbiotic?

3 Comments
2023/09/16
01:55 UTC

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