/sci/ - Science & Math

>>9455661
The theory changes because we can't really turn back time and look for ourselves. Scientists are only able to work off of what has been discovered thus far- with the media overhyping every change to the current model of understanding because it's a hot button topic that gets a lot of viewership.

Your question is kind of lost in the second half. I'm going to run off of the assumption that you're asking at what point can we say that homo sapiens became a continuous 'species' separate from another, correct me if I'm wrong. The answer to that is that it is incredibly arbitrary- we define a species now typically by taking a population of them and comparing the genetic variation within that population and comparing it to another population of an organism- if by the quantitative nature of their genomes there is a significant amount of difference between the populations that is larger than within, we call it a separate species- or if it's a lower amount, we call is a subspecies or a variant or whatever.

So the answer on that level is "whenever the population that gave rise to homo sapiens became more genetically distinct, holistically, than the populations of their predecessor species". But I'd probably argue for humans there's the exceptional case of higher intelligence, or even language- those traits, I think would be the ones to argue of when "humans" really began. Given that you can't really check for those in the fossil record, we can only go off of what we are able to date in terms of tools and the like that were obviously made intelligently, and even that will have a degree of uncertainty so high that the model will exist in flux for some time.

>>9455661
>what is the collinearity of HOX genes

>>9455677
No, my main question was how do we proceed that the theory of evolution is a concrete fact.
Because I just saw a couple of people going
>Hurr Durr this politician doesn't believe in evolution, he's such a retard, we're so intelligent

I might not agree with the politician, but argumentatively how do we proceed we actually evolved from an aquatic species

>>9455682
I really don't know what it is, care to explain it in a simple way

>>9455685
We use quantitative genomics for the most part now to determine the order of how evolution occurred.

https://genome.ucsc.edu/ is a good tool to be able to browse the genome in an interactive sort of way, and one of the functions that's turned on from the start is it shows you all of the overlap between humans and other species in terms of the exact sequences of DNA that are identical.

Since we know how genes can mutate, how genes encode for proteins, and how those proteins make structures, evolution is more of a phenomenological process that is observable than it is a theory.

https://www.youtube.com/watch?v=plVk4NVIUh8 is a fantastic 2 minute video which displays some of how natural selection itself works to differentiate an organism in real-time.

>>9455685
first fish developed legs then lungs and yeah

>>9455661
>The theory of where we originated in always changing.
No, the hypothesis of where we originated is changing. The theory is not changed.

>>9455685
>how do we proceed that the theory of evolution is a concrete fact.

>>9455688
fly and human had a common ancestor that already had a hox gene cluster that determined front and back of the body
today, humans and flies have a unique genetic setup that is still derived from that of the common acestor

>>9455711
So the theory still is we originated from one common ancestor
>>9455718
Which we share with flies and many other species?

>>9455661
>counter arguments against evolution

>>9455661
toaster oven repair mechanics is a science.

>>9455895
and with many others we dont. and it's even gradual. can you imagine that?

>>9455906
and then he even said
>We're always discovering older fossils that push back the age we thought humans existed or existed intelligently.
which is so generalizing it's simply wrong.

>>9455895
It's called homeotic genes. They are greatly conserved through species and are implicated in the body plan.

>>9455929
It's not, Spears were found in Germany, which pushed back the date we thought humans existed as tribes by 400,000 years

Its accepted as fact because theres not another evidence based theory to challenge it.

>>9455962
200,000 years ago: first appearance of Homo sapiens in Africa

>>9455661
> I'm not talking about mutations, I'm talking about evolution
feels good knowing I will never be this retarded

>>9455974
God created humans

>>9456005
>Being this retarded
Having an extra finger on your hand is a mutation, not evolution. Go kys

>>9456020
Even as a Christian, I admit that we have no observable evidence to support this as a scientific theory. I think there are still plenty of explanations for how God created humans and evolution can coexist, but I wouldnt call them any more than speculation.

>>9456024
Mutations are one of the tools of the evolution

>>9456024
But if, for example, a person gained an extra finger, and it was a dominant gene, then they could move onto an island with 3 other people, and a lineage of people who have 6 fingers would exist on said island- assuming it doesn't hinder fitness much, it'll be neutral and be carried forth primarily due to it being a dominant gene, and so you'll see a population of people who are entirely 6-fingered. If you have a population that has a different allele ratio than before, then you can say that evolution has occurred. Mutations are the source of new alleles, "evolution" is the change in allele frequency within a population. Technically adding a new allele does change the frequency- but in individuals it's usually dismissed unless there's a founding event where a small selection of the population (sometimes even as low as 2- a male and a female) end up genetically isolated from the original population.

Usually mutations aren't big things like that. Often times they're small changes in protein structure that might affect how efficient certain biochemical processes are, for example.

>>9456045
That might be true but mutation=! Evolution

>>9456053

There is no evolution without mutation.

>>9455661
>Reading up arguments and counter arguments against evolution.

Why? We've documented it in action now.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2830240/

Also,
>"The Beak of the Finch: A Story of Evolution in Our Time" By Jonathan Weiner

The weirdest thing is that thier beaks are changing yet again to adapt to the presence of food trash left by residents and tourists of modern day Galapagos. This stuff is just one of many such modern day recordings of evolution in action.

So really, who gives a shit about this "debate" since it is completely a moot point now? Hell, you can do it yourself with fruit flies if you have the time.

>>9455962
>>9455978
>always

>>9456058
>>9456053
I think he means that it is only evolution if that specific mutation is carried through genes to the offspring. Like how mutation due to disease, radiation, etc normally won't be passed along.

>>9456058
>>9456053
>>9456045
>>9456024
mutation + selection = evolution

>>9456069
I can see where that can be the point, but usually mutation is only talked about in the germ cells, or just generally in what is heritable. But I can see that argument, and it's important when explaining to people how biological systems works to mention the premise that mutation must be heritable. It's the same line of reasoning for as to why people confuse what gene therapy is capable of in an individual vs. what the same techniques are able to do in sperm/eggs.

>>9456072
Not to be one of those "Aktchshually" faggots, but mutation + selection + genetic drift = evolution, where selection is a broad term that encompasses natural, artificial, and sexual selection pressures.

The genetic drift part is far too often underestimated, and is the primary point that the layman who knows a bit of biology won't understand about evolution.

>>9456077
>mutation + selection + genetic drift = evolution
A+B+(A+B)=C

>>9455661
>We're always discovering older fossils that push back the age we thought humans
>As time passes things get older,
Brainlets everybody

>>9456271
>As 15 year passes things get 40,000 years older
Go ask your mom to buy you a blade, and then shit right down on your wrist

>>9455694
Actually, that brings another point to mind that I've been wondering; how would this end up occurring? You're not only going to need to be able to breathe air, one would also require some form of leg or at least flipper to be able to move around, and it seems that fins are generally better for pure undersea life, given what those types of animals typically present as; how would one just happen to have both land-compatible lungs as well as a proper form of propulsion in order to move effectively on land?

>>9456828
The evolution of land-based life from fish is probably the most well-understood of the major evolutionary choke points. Wikipedia has a good article about it: https://en.wikipedia.org/wiki/Evolution_of_tetrapods#Origin

tl;dr:
>heavy species of fish (heavy enough that no sinking is a substantial challenge) started carrying air balloons for better buoyancy
>these fish were also fairly active, and that carried air was also a convenient source of extra oxygen; lungs developed as an addition to gills, then more sophisticated breathing mechanisms
>the luxury of a secondary oxygen supply allowed these animals to start living in the shallows, where gill-only fish cannot survive because of unreliable oxygen supply, which makes it a safe niche
>living in shallows and swamps makes a change from fins to legs practical; early forms probably looked much like modern mudskippers
>all the basic components are now in place, and the path is free for amphibians to arise. The further inland you go, the more ability you have to be the only player in town, so there is pressure for steady development in this direction
>eventually you have modern-ish amphibians, which rely much more on water than mammals and reptiles do but still live most of their time on land
>from here on, getting rid of the last ties to water-based life is a long but straightforward process; google Amniotes

>>9456977
>the transition is extremely well understood
>they just magically grew lungs

sure thing buddy

>>9456993
>There are fish living right now that have lungs in addition to gills
>M-m-magic!
You are retarded. I'm sorry your wacko parents brainwashed you into denying basic scientific facts, but that doesn't mean you can come here and shitpost.
https://en.wikipedia.org/wiki/Coelacanth

>>9456993
>be fish
>have air sac for buoyancy, gulp air to fill it
>live in low-oxygen environment
>mutation arises that causes lining of air sac to have denser capillary coverage
>gas exchange happens through diffusion, so more blood vessels exposed to air = more oxygen entering bloodstream
>mutation allows carriers to be more active due to increased oxygen supply
>mutation goes to fixation
>later, another mutation arises causing lining of air sac to be wrinkly
>wrinkles = increased surface area = more oxygen gained
>and so on
it's like you're terminally unimaginative or something. it's like the people who can't understand how the vertebrate eye could have evolved.

>>9456144
Correct me if I'm wrong, but I don't think genetic drift is mutation + selection. Selection is inherently directional relative to a pressure, whereas genetic drift is the notion of randomness applied. Yeah mutation creates allellic variants that genetic drift acts on, but it doesn't create the phenomenon itself I thought.

I was taught there's five mechanisms of evolution

>>9457050
There sort of is. I just count all selection together in thinking about how you can model it- since they're just different forms of the same mechanistic kind of pressure towards a certain allele. I also tend to omit migration when talking about allele changes, since it's so difficult to meaningfully analyze how populations converge together- it's a lot easier to model and deal with discussing founding events and populations splitting up.

That isn't to say that migration isn't an important mechanism- it is, it's just something that becomes a little more difficult to talk about on the level of laymen.

>>9456020
God created Adam from clay, which contains plenty of microorganisms that would supply the genetic makeup of man and aligns man into our glorious clay heritage that became living things thanks to the miracles of God. It all fits perfectly.

>>9456024
And if having an extra finger helps me survive it is selected for and you have evolution, the only other factor is genetic drift.

I reassert my original point that it feels good to know I will never be this retarded.

>>9457025
>have air sac for buoyancy, gulp air to fill it
Or even simpler: just take a mouthful.

I dont understand why people dont understand evolution.

>>9457025
muh nigga that fossil is one of the earliest known birds

>>9457025
>it's like you're terminally unimaginative or something
Thats honestly exactly what it is, MUH GOD MUH INTELLIGENT DESIGN, THERe IS NO WAY THIS IS FROM CHANCE

>>9457025
So, basically, you believe magic is real.

>>9455661
Evolution is false since it would follow that humans could have diverged genetically and something like "race" could have been developed.

That is false.

>>9457507
Cathy Newman pls go

>>9457037
Genetic drift is simply the fact that some organisms may produce more offspring based on chance, not because they have a gene that increases their fitness (selection). Genetic drift is somewhat random, but we do know it tends to decrease genetic diversity (loss of heterozygozity).

>>9457037
>>9459112
Also, genetic drift can occur with or without selection and is also not reliant on mutation, but mutation does add new alleles that may undergo drift.

>>9455661
A good point, related to something I discovered recently related to evolution: The main story people want us to believe is that 4-6 million years ago, humans didn't exist, and that we had a common ancestor with a chimpanzee. They say that this "wan't a chimp" but that it also "wasn't a human." So that means it would have to have features of both. The problem is, chimpanzees don't have features of both, and humans don't have features of both. If humans and chimps don't have features of both, then how could the common ancestor have features of both? That means either humans evoluved from chimps, or chimps evolved from humans. Obviously since humans are more advanced than chimps, the humans must have "evolved" from chimps. However, if chimps evolted into humans, then how are there still chimps? According to evolution, birds evolved from dinosaurs, therefore there are no dinosaurs left. If humans evolved from chimps, then IT MAKES NOT SENSE FOR THERE TO BE ANY CHIMPS

>>9459152
Humans and chimps share lots of features. Youre just a cunny.

>>9457450
>imagine being this retarded
Your mom must be a brave lady not to abort you

>>9459112
>>9459121
Yeah, that's what I'm saying. The other anon said that genetic drift was selection + mutation, which seems a bit sketchy to me since genetic drift is a phenomenon that occurs separately from those mechanisms alone. Genetic drift is always something to keep in mind when talking about evolution and evolutionary pathways- just that most people don't deal with it unless they've learned real biology.

>>9459152
The state of the American education system, everybody.

>>9459152
chimps could pretty well have evolved from humans. Environment and a chance to reproduce here dictates to what traits will be developed more. Most chimplike bros had genes which equipped them with traits mostly favorable for reproduction there and theese genes won there you could say.
>advanced
remember, in what sense? evolution is not about an objective advancement. Check out what human traits are naturally selected the most right now and discover that is certainly not iq

>>9459185
Watch out, baby whos that, dont look down theres a monkey on your back.

>>9459185
Yeah, drift is so fundamental to evolution, yet is brushed aside or not even taught in high school biology. I think population genetics should be a required part of a biology class, but I guess the math scares people away.

>>9459201
Why..

>>9459208
Why should is drift not taught? Why should population genetics be required or why does math scare people away?

Divine creation is scientific fact, Dr. Hovind has been BTFO'ing evolutionists for decades now.

>>9459233
At least try with your bait.

>>9459201
At my uni, the biology program's intro course is evolution and systematics, then the next two courses go over molecular/cellular/developmental, and plant/animal physiology. The way it was structured was leagues better than the shit I remembered in highschool where it was a grab bag of facts about taxonomy and physiology with a sprinkle of ecology.

While I did my major in molecular bio, I have a soft spot in my heart for population biology, evolutionary biology, and systematics.

>>9459233
this is your daily reminder to read """""Dr.""""" Hovind's """"""""""dissertation""""""""""
https://file.wikileaks.org/file/kent-hovind-doctoral-dissertation.pdf

>>9459286

It's perfect.

>>9459152
>The problem is, chimpanzees don't have features of both, and humans don't have features of both
Humans and Chimps share more than 90% of their features.

>>9455712
>how do we proceed that the theory of evolution is a concrete fact
>lmao luk at this brony shit ponies are rats lmfao xDD

>>9459599
you can kys now

>>9456063
Evolution as a biological process being true does not generate the theory that humans have evolved from apes being automatically true.

>>9459604
Not an argument

>>9459183
>haha I have no argument because ive never taken a biology class in my life
Thinking mutation isnt involved in evolution means you either a) dont think that evolution is real or b) you have a better model than evolution. Im waiting with baited breath for you 2000 IQ answer.

>>9459634
Highly advanced retort considering you didn't either.

Would you be pounding your fists against your booster seat if the example wasn't horse related? Your pony shitting is not welcome here.

>>9459286
I hope he was fired from being a high school science teacher like wtf.

>>9459940
I wasn't even the pony poster, just calling you out on your bullshit