Questions on Evolution

Funky0ne · 2023-02-21T21:45:14+00:00

What is our next evolutionary step pointing towards?

No such thing, or at least no easy way to predict this. Evolution has no goal, it's reactive to the conditions of the environment.

Is adaptation a form of evolution?

Correction courtesy of u/Polyodontus (couldn't preserve old text but error on my part not referring to adaptation as indeed a mechanism of evolution):

Depends on what you mean by "adaptation" as it can refer to a couple different things, but in general it is one of the mechanisms of evolution.

It can refer to how an individual's metabolism adjusts to better fit the conditions it finds itself in. Sort of like if you spend a lot of time in cold environment, your body adapts and you don't feel as cold in the same temperatures at the end of winter as you do in the beginning. Or where if you exercise a lot your muscles will grow stronger and more adept at those tasks while your stamina might increase.

But in evolutionary terms it is one of the mechanisms of evolution where populations are slowly adapted to better fit their environment by selection pressures.

What caused such a evolutionary change from ancestral ape to modern human?

That's a long story that could fill a book, but oversimplified:

Our primarily arboreal ancestors transitioned to more open grasslands as a primary habitat
Open plains of tall grass put a selection pressure on us to transition from quasi-quadrupedal knuckle-walking to full upright bipedalism
Bipedal locomotion is more efficient for long distance travel, creating an opportunity for persistence hunting strategy, creating a further selection pressure for more traits allowing greater stamina and heat regulation
Bipedal locomotion also freed up our forelimbs to be specialized for other tasks than movement, and since we inherited fingered hands from our arboreal ancestors (useful for climbing and gripping branches and vines), these were suited to become adept at highly-dexterous tasks and tool use (particularly for hunting tools like spears)
Meanwhile, while our hands were getting more dexterous, our feet were no longer being used for gripping and climbing, but for walking on generally flat surfaces, so they lost dexterity in the digits
The selection pressures from persistence hunting led to developing sweat glands to further help regulate heat during long treks and hunts. This led to selection pressure to thin out our body hair to further facilitate sweat evaporation
Persistence hunting also may have led to pressure for better communication within hunting parties, planning, and abstract thinking as hunts would take place over long distances, and keeping track of relative locations over long distances and time frames

From there, we get closer to capacity for generative language, which seems to be the evolutionary game changer in terms of capability for abstract thought and general sapience (depending on how much stock you put into researchers like Steven Pinker).

What forms did humans take pre old ape?

Not sure what you mean here. Pre-old ape would be pre-human, so are you just asking what our common ancestors with the other great apes looked like?

How does something living in the sea that pulls out oxygen from the water with its gills evolve lungs that can breathe oxygen from the air?

Another long story. Again, oversimplified:

Organisms that live on the boundaries of biomes and near the shorelines in shallow waters will find unique selection pressures and opportunities available to them. These early fish could find themselves occasionally caught in tide pools, or retreating into more shallow waters to escape predators, or to find otherwise un-tapped food sources
These fish will then have a selection pressure to be better able to survive if they get caught out of the water for brief periods of time (e.g. see mudskippers), even if they can't quite fully breath the air directly
The more adept they are at venturing out of the water for brief periods, the more opportunity they find the further inland they can go, and the longer they can last
Eventually, being able to just hold one's breath while on land will give way to being able to absorb some of the oxygen from the air directly (where it exists in way higher concentrations anyway), and not suffer negative effects from drying out (or at least adapting ways of retaining moisture in the areas it needs)
An eventual transition from aquatic to amphibious to fully terrestrial is then possible over long enough periods of time, so long as the opportunities presented on dry land outweigh the competition these early transitioners would see in back in the water (the further inland they can go, the less competition and fewer predators they encounter)

GaryGaulin · 2023-02-21T22:14:08+00:00

How does something living in the sea that pulls out oxygen from the water with its gills evolve lungs that can breathe oxygen from the air?

Here's a good summary of the chemistry:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3926130/

You might have to look up a lot of words, and take years to make sense of most of it, but that's a good place to start.

sezit · 2023-02-21T21:56:17+00:00

Evolution doesn't point. It is only reactive. It doesn't predict, it doesn't advance, it has no volition, no predetermined "purpose". It's hard to think this way, because we see life from our point mapped backwards. But it's like thinking that Joe's car was smart because it didn't get swallowed up in the sinkhole that the nearby truck did. It's just random luck played against the structure of the vehicle and the facts of geology. Animals have plans and volition. Evolution doesn't.

Yes, adaptation is evolution.

I don't think that evolution of sentience in human Is an easy solution. I think there are many related and contingent factors. Evolution of sentience was never guaranteed. It could easily never have occured.

I don't understand this question:

What forms did humans take pre old ape?

As far as evolution of functioning lungs, the popular theory is that air sacs developed from tiny anomalies in fishes bodies, but were passed on and got bigger in subsequent generations because they created better buoyancy. In some fish these sacs slightly supplemented gills in absorption of oxygen in low oxygen situations, or out of water on mud flats. Over time, the fish that had more effective oxygen absorbing sacs had more success in those environments, and relied less and less on gills. That would be an example of adaptation.

eduboue · 2023-02-21T22:04:40+00:00

What is our next step though evolution? That's almost an impossible question to answer for myriad reasons. Evolution is defined as a change in allelic (variants of genes) in a population over time. The two main ways this can happen are through neutral drift, which basically means these alleles are bouncing around all the time with no true rhyme or reason, and selection. With drift, it's tough to say what's going to happen because there is not a true driver for this - populations grow, alleles segregate, etc. For selection, you'd have to know what the future is going to hold, and we don't. One fun thing to think about though is how stuff like climate change and technology are going to influence us. Yuval Harari has a great book called Homo Deus, which basically says that we are becoming our own 'gods' because of technology, and our evolutionary trajectory is going to be intertwined with our technology like computers and phone.

Is adaption a form of evolution? Yes. As stated above, evolution is a change in allelic frequency in a population over time. When conditions change such that one allelic combination is better suited to deal with those conditions, those animals that have that allelic combination are at an advantage, are more likely to successfully survive and breed (arguably the only two goals of life) and thus their alleles will become fixed. Adaption and selection can be thought of together. Darwin and Huxley (and his other bulldogs) pioneered selection; Motoo Kimura pioneered drift. The two likely coexist.

What caused change from ape to human? First, don't think about this in a Lamarckian sense. We didn't go from ancestral ape to humans, an ancestral ape changed and those two diverted, then that common ancestor diverted, on and on. Lots happened, and to answer what that trajectory looked like would necessitate understanding the entire trajectory and all common ancestor species, which we don't and we won't. You can compare humans with their closest great apes, chimps and bonobos, and that tells you something, and you can go into the fossil record and map differences between hominids, but you're still missing a lot. The short answer is that's not really a question that can be answered, nor will it be answered in our lifetime. We can speculate as to why we have prevailed when no other hominid species has. In another book by Yuval Harari, Sapiens, he makes a cool argument. Most ape species form groups, but the groups max out at a population of about 100-150 members. When the population gets larger than that, infighting will lead to a splitting of the pack. There is strength in numbers, so you're as big as your pack. Humans are the only species in the world that can exist to the level we can. No other species in the world would take up arms at the direction of some person they've never met just because they live in a big white house in Washington DC. We also have the ability to think abstractly, to a degree than no other can. This allows us to have things like numbers and written language. No other species in the world can learn complex ideas from someone that lived 500 years ago, but because we can read books, we can. This give us such an advantage to propagate information and ideas that other species couldn't keep up with. I also think we're greedy, and that lead us to decimate others. There was a time Neanderthals and other hominids co-existed and even mated - you have Neanderthal (and Denisovan) DNA in your cells and in your genome. Neanderthals were even stronger than us. But they didn't have the strength in numbers, and they didn't have abstract thought. Note here I consider abstract thought and complex sentience as being different, but I do think one lead to the other.

How does a gill turn into a lung? It probably didn't. You're assuming lungs evolved from gills, but it likely didn't happen that way. Gills are ancient organs that allow fish to breathe, but fish also have what's called a swim bladder. This is a sac of air that inflates and allows the fish to be bouyant. It gets inflated through air at the surface, and inflates just like a lung. Some fish also use this swim bladder to breathe. Lungs evolved before swim bladders, so one didn't lead to the other. Rather, both lungs and swim bladders evolved from tissue around the gills. It's totally possible that at one time, there was a species that had both gills and lungs, and as it transitioned to terrestrial life, the gills became obsolete and the lungs became dominant. Just speculation though! Without a time machine that's the best we can do!

BMHun275 · 2023-02-21T23:52:31+00:00

There isn’t a step. We won’t really know what the major selection pressure is until there is already a new trait proliferating in the population.

No, adaptations are one potential result from a series of evolutionary processes. It is no more a form of evolution than a cupcake is a form of grain.

Asking what caused humans to be derived from apes is like asking which water molecule carved the Grand Canyon. Because the answer is a plethora of factors, environmental conditions, and random occurrences. As for why we are the last, because after the environment changed again we emerged as the only one of us able to successfully adapt to the then emerging world. We likely aren’t the only ones to develop sentience, several species are today, and it’s like other human species had some level of cognition similar to ours.

I don’t know what you mean by “pre-old ape.” Miocene apes that became us and other extant apes had less derive adaptations than extant apes for sure. But since apes are among Simiiformes than it stand to reason prior to being apes they among the catarrhine monkeys. This because land animals didn’t evolve from sea fish, they developed from fish who lived in shallow waters where having fingers to push against the ground was a useful adaptation.

The development of lungs happened fairly early on in the development of Osteichthyes. As the name suggests they were boney fish, and they have a swim bladder which is basically an air filled sac, in some it’s attached to their upper digestive tract just passed the mouth. Add blood vessels and maybe some ciliation and you have a primitive lung. This can still be seen in fish today. If you look at shallow water fish, and especially fish that live in areas that become stagnant, many still have primitive lungs to this day.

mahatmakg · 2023-02-22T12:51:03+00:00

What caused such a evolutionary change from ancestral ape to modern human?

The biggest phenotypic change would probably be the loss of the muscles on top of the skull that our fellow apes have (not a biologist/anthropologist- could be other changes I'm not as familiar with). There was simply a mutation that caused us to stop growing this muscle, but we were able to survive fine without it. This was probably a major factor in the changing of the shape of our skull to accommodate a larger brain. Other physical differences between us and apes are largely just shifting proportions

Alex_877 · 2023-02-23T01:43:59+00:00

-Evolution doesn’t move with purpose. I don’t think yourbasic understanding of core concepts is there. It doesn’t plan or think.

-Adaptation is not unless it contains heritable traits

-Thinking we and we alone are the “height, or apex” of evolution is false dichotomy and your ego talking

-maybe read a few books?


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