We have been in competition with the animals on this planet since we arrived. Commercialization has certainly caused some avoidable consequences to animal populations, and I agree we ought to take care of the earth as well as we can, but I just can’t get worked up on the animals’ behalf over our ancient ancestors killing them and using basically every part of the carcass in an effort to survive.
Oh don't worry, no one is expecting you to get worked up about it. It's just that we all tend to have this attitude that we are the pinnacle of nature's great evolutionary process, when pretty much all evidence suggests we're a bunch of bastards to most life on Earth--and each other, incidentally. Go humans?
This is what I disagree with. Evolution is not a process that is maximizing anything. What survives just survives. We got stuck in a feedback loop that optimized brain size for evolutionary fitness, but we're stuck in a tiny fractal corner of a corner of a corner of the entire space of biological life. E.g. Tardigrades (https://en.wikipedia.org/wiki/Tardigrade) are extremely successful at survival in a huge variety of conditions, and very stable over millions of years without a lot of genetic drift. Similar for cockroaches. We don't consider these "pinnacles" of evolution just because of our arbitrary value system. Yet cockroaches (and all insects, really) serve extremely important jobs in ecosystems which would collapse without them.
I assume by "pinnacle of evulution" you mean the currently most successful species in terrestrial ecosystem on the planet Earth. Surely there is no "pinnacle" to all of evolution, whatever that would even mean.
You seem to be implying that evolution is a process with some ideal, perfect outcome that can be achieved, or you're just being sarcastic. I can't tell but both are silly.
I didn't introduce the word "pinnacle" to this debate, titzer did. I just thought it was ironic that he/she was using his/her moral judgement to criticize the human species in such a way.
I introduced it as a strawman, just trying to be terse. You embraced it to say that we must be at some kind of pinnacle to be able to make moral judgments. I started by pointing out facts; despite the perjorative term "bastards", it's pretty undeniable that humans have pretty much decimated every other form of life that is either a competitor or not a domesticated food source. As for "blind", that's not a moral judgment, whereas "immoral" clearly is. I admitted that both are my opinion, not fact.
Of all the species mentioned in this thread, only one can sit in front of a computer and type out their opinions about evolution. So, yeah, we're the pinnacle of evolution at least as far as Earth is concerned.
We could kill any animal on Earth effortlessly. We’re the fittest. From an evolutionary standpoint I’d say we won. I’m not saying we’re better, but arguing that humans aren’t the most advanced species really serves no purpose other than pedantically pointing out “many other ways” in which we can define pinnacle. You know what the parent meant.
My point, and I'm not just being pedantic, is that there is nothing to win.
Humans are the most advanced species? By which metric? Intelligence? Perhaps. Strength? No. Sheer numbers? No. Impact on the environment? Arguably (plants, though not a single species, would probably win that). You might as well say we're the most advanced species because we're the only one that cares enough to give ourselves a trophy for it.
Evolution is not a game to be won nor a process with an end or a goal. We weren't here before, we're here now, and we likely won't be here forever. We're ephemeral.
There is a lot of time for better chances to come along. Depending on the estimate, we're not yet halfway through the lifetime of the sun, that's plenty of time for a more successful successor to humans. And the Earth didn't even exist for much of the first half of the sun's lifetime.
The lack of alien contact suggests to me that technological civilizations don't appear very frequently. So I'm afraid that we're somewhat of an evolutionary aberration and if we'd go extinct a replacement wouldn't arise.
> All creatures try their hardest to out-compete everything else.
When we take a wider look at life, this just isn't universal. If you look at ecosystems in very stable environments (e.g. caves), the ecosystem as a whole tends to come into balance over time, where species are not aggressively try to outcompete their competitors, but instead fit into comfortable little niches so that the system as a whole keeps functioning well. In fact, evolution works on the ecosystem scale as well, and systems with aggressive species tend to be very unstable and prone to crashes. In environments with constant change, then ecosystems are constantly changing and competition becomes more fierce, benefiting aggressive species. This is not always the case, so I don't think it's useful to assume that everything is trying to move as aggressively as possible; otherwise evolution would select against species with long gestation periods and tend towards shorter generations and faster growth.
There isn't any particular reason to privilege caves or other "stable" habitats. This is an incomplete understanding of them, anyway. Because caves are nutrient-poor, it is common that all animals there are extremely lethargic. That is not the same as lacking aggression or competition. Cave animals strive to survive as fiercely as anything in the jungle, just at a much slower pace. If a more active predator were to be stranded in a cave, it might eat everything it can find in a week, and then starve. Within months, other animals from more remote corners of the cave would scavenge its carcass and repopulate.
To visualize this, watch one of those speeded-up videos of starfish and sea urchins. At our pace, they are sedentary. At their pace, it's Thunderdome all day every day.
Caves were just an example, and pretty much the rest of your comment actually proves my point. If a "more active predator" enters a cave and subsequently eats everything and dies, then evolution has selected against it. Evolution selects species that best fit the environment, and that generally means species that find a sustainable balance through both internal and external regulation mechanisms.
Your example doesn't require an invasive species. Aggressive species (ones with their consumption and reproduction clocks set "too high") can arise through mutation, too. In either case they spread like cancer and usually take down parts of the ecosystem with them before they are finally selected against. Eventually, ecosystems find mechanisms to limit the damage of cancer-like species and adjust everyone's "clocks" to appropriate levels. Ecosystems that cannot bring their species into stasis experience repeated shocks, are less stable than ones that do find stasis, and often disappear. This is exactly why the long arc of evolution is best understood as a punctuated equilibrium (https://en.wikipedia.org/wiki/Punctuated_equilibrium) rather than a constant drift. Systems that find stasis are more successful than ones that don't. Unfortunately these systems are repeatedly interrupted by drastic environmental changes like geological events. So, the systems that survive are the ones that tend toward balance but are able to adapt to occasional disruptive events. That requires biodiversity that is generally reduced by aggressive species.
> To visualize this, watch one of those speeded-up videos of starfish and sea urchins. At our pace, they are sedentary. At their pace, it's Thunderdome all day every day.
Or look at hardwood forests that develop extremely slowly over thousands of years, despite the availability of plenty of energy from the sun. The slower the system, the better it actually proves my point. Clearly, evolution does not select for the fastest growing, most aggressive species out there. Otherwise starfish and sea urchins would move faster, or be displaced by something that moved faster.
Properly understood, ecosystems are super organisms that require many many moving parts to bootstrap, grow and function. Human bodies are analogous. Your cells aren't trying to "outcompete" every other cell in a Thunderdome situation every day. They are carefully regulated both internally and externally. When those regulatory mechanisms fail, you end up with cancer and you die. Clearly, cell replication rate is a key regulator internal to a cell that prevents us all from experiencing runaway cancer and dying. Clearly ecosystems have species with internal regulation mechanisms as well.
As a human, I want humans to have great lives. Part of that means taking care of your things. People like to say, "The Earth doesn't belong to us, we belong to the Earth," but I would contend we are best equipped to take care of it, and it's for our own benefit. Taking ownership of the little piece of it we interact with on the daily isn't all that daunting of a task.
Big animals that evolved alongside us (elephants, lions, hippos, etc) have not been wiped out. Most of the North American big mammals got wiped out because they were suddenly exposed to human big-game hunters who had been hardened by thousands of years of living in the Siberian wastelands. Those North American animals didn't have the benefit of a long genetic memory telling them that the soft hairless ones are actually the most deadly predators on the planet...
Hunger will make you do some crazy things. I can only imagine the feeling in a Paleolithic society when your group succeeded in taking down something like a mammoth - it’s like completing a major contract which will have your whole family living well for months. A prey animal is naturally as important a resource for humans as it is for a tiger.
Of course, like many ancient traditions this looks completely different in modern times.
But, when did Sloths lose their energy? I have seen videos[1] of Sloths crawling/slithering slowly across a road, and cannot imagine they were ever a formidable or challenging target for (pre-)humans.
I don't know the answer to your question but I wouldn't compare modern sloths to ancient ones. They're each adapted for completely different environments.
That's exactly the point of the question, though: when/how did sloths transition from "ancient" to "modern"? If ancient sloths were massive and formidable prey, as per the article, what happened? Were there always smaller and/or slower sloth varieties, and we just killed all the giant ones?
EDIT: As always, Wikipedia comes through [1]. There were species of different sizes, with tree sloths always being smaller than ground sloths [2], the giant of the article
Alternatively it could be argued that increasing temperatures and abundance of food favored smaller animals (including our very low-tech ancestors), which pushed the proverbial mammoths out of their ecological niche and into the oblivion.
The smaller the animal, the larger skin_surface:body_mass ratio, thus higher heat loss. The smaller the animal, the shorter the intervals between feedings it can tolerate. A large-bodied animal can go for longer period of time without food, especially if equipped with slow metabolism. In contrast, smaller body and faster metabolism requires frequent feeding, but also allows an animal to out-compete slower, larger ones both in food search, and by out-breeding them.
For any given body plan, an animal can only cover distance roughly relative to its body size; the smaller animal, the harder time it will have to find sufficient food on sparse, hardy cold-climate vegetation. On the other hand, once denser, warm climate vegetation takes hold, it allows smaller herbivores to live in higher density, and with higher breeding rate.
If I remember my biology right, the more an animal has specializations for particular environment or niche, the slower it will adapt to changed circumstances, both in body build, and in behavior & seasonal migration patterns.
Last but not least, a predator population requires certain density of prey to be sustainable. Once plant food becomes abundant due to warming up, and herbivore population grows, the population of predators can be established, and cull the large bodied animals unadapted to heavy predation.
Well, sure, I'm sure climate changes helped push North American megafauna populations over the edge -- except the TFA speaks specifically about archaeological evidence of specific hunting events, including human foot prints following giant sloth foot prints in a pattern which implies stalking and hunting and even the sloth rearing up to defend itself.
The reason we believe that humans wiped out the mega-fauna is because the megafauna of North America all disappeared within a millennia of humans arriving from the land-bridge. It's possible they all coincidentally disappeared but unlikely.
I don't consider it unlikely at all considering that the human entrance into N. America coincides with huge climate change events - the Younger Dryas cold snap followed by the abrupt and quick Holocene warming event. It's even possible that the human migration was a result of looking for favorable conditions as climate change made their traditional hunting and foraging areas untenable.
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[ 4.6 ms ] story [ 84.5 ms ] threadhttps://www.theatlantic.com/science/archive/2018/04/in-a-few...
> bunch of bastards to most life on Earth
seem almost synonymous, unfortunately.
This is what I disagree with. Evolution is not a process that is maximizing anything. What survives just survives. We got stuck in a feedback loop that optimized brain size for evolutionary fitness, but we're stuck in a tiny fractal corner of a corner of a corner of the entire space of biological life. E.g. Tardigrades (https://en.wikipedia.org/wiki/Tardigrade) are extremely successful at survival in a huge variety of conditions, and very stable over millions of years without a lot of genetic drift. Similar for cockroaches. We don't consider these "pinnacles" of evolution just because of our arbitrary value system. Yet cockroaches (and all insects, really) serve extremely important jobs in ecosystems which would collapse without them.
Humanism is blind and immoral, IMO.
That's a judgement that a human can make only because our species reached the pinnacle of evolution.
You seem to be implying that evolution is a process with some ideal, perfect outcome that can be achieved, or you're just being sarcastic. I can't tell but both are silly.
Whales are the largest animals alive today, so perhaps they're the pinnacle of evolution.
Implying there's a "pinnacle" of evolution implies evolution has a goal or intended outcome, which it does not.
Humans are the most advanced species? By which metric? Intelligence? Perhaps. Strength? No. Sheer numbers? No. Impact on the environment? Arguably (plants, though not a single species, would probably win that). You might as well say we're the most advanced species because we're the only one that cares enough to give ourselves a trophy for it.
Evolution is not a game to be won nor a process with an end or a goal. We weren't here before, we're here now, and we likely won't be here forever. We're ephemeral.
On the other hand, we're also pretty much the only chance for terrestic life to survive the end of our solar system.
When we take a wider look at life, this just isn't universal. If you look at ecosystems in very stable environments (e.g. caves), the ecosystem as a whole tends to come into balance over time, where species are not aggressively try to outcompete their competitors, but instead fit into comfortable little niches so that the system as a whole keeps functioning well. In fact, evolution works on the ecosystem scale as well, and systems with aggressive species tend to be very unstable and prone to crashes. In environments with constant change, then ecosystems are constantly changing and competition becomes more fierce, benefiting aggressive species. This is not always the case, so I don't think it's useful to assume that everything is trying to move as aggressively as possible; otherwise evolution would select against species with long gestation periods and tend towards shorter generations and faster growth.
To visualize this, watch one of those speeded-up videos of starfish and sea urchins. At our pace, they are sedentary. At their pace, it's Thunderdome all day every day.
Your example doesn't require an invasive species. Aggressive species (ones with their consumption and reproduction clocks set "too high") can arise through mutation, too. In either case they spread like cancer and usually take down parts of the ecosystem with them before they are finally selected against. Eventually, ecosystems find mechanisms to limit the damage of cancer-like species and adjust everyone's "clocks" to appropriate levels. Ecosystems that cannot bring their species into stasis experience repeated shocks, are less stable than ones that do find stasis, and often disappear. This is exactly why the long arc of evolution is best understood as a punctuated equilibrium (https://en.wikipedia.org/wiki/Punctuated_equilibrium) rather than a constant drift. Systems that find stasis are more successful than ones that don't. Unfortunately these systems are repeatedly interrupted by drastic environmental changes like geological events. So, the systems that survive are the ones that tend toward balance but are able to adapt to occasional disruptive events. That requires biodiversity that is generally reduced by aggressive species.
> To visualize this, watch one of those speeded-up videos of starfish and sea urchins. At our pace, they are sedentary. At their pace, it's Thunderdome all day every day.
Or look at hardwood forests that develop extremely slowly over thousands of years, despite the availability of plenty of energy from the sun. The slower the system, the better it actually proves my point. Clearly, evolution does not select for the fastest growing, most aggressive species out there. Otherwise starfish and sea urchins would move faster, or be displaced by something that moved faster.
Properly understood, ecosystems are super organisms that require many many moving parts to bootstrap, grow and function. Human bodies are analogous. Your cells aren't trying to "outcompete" every other cell in a Thunderdome situation every day. They are carefully regulated both internally and externally. When those regulatory mechanisms fail, you end up with cancer and you die. Clearly, cell replication rate is a key regulator internal to a cell that prevents us all from experiencing runaway cancer and dying. Clearly ecosystems have species with internal regulation mechanisms as well.
Of course, like many ancient traditions this looks completely different in modern times.
[1] https://www.youtube.com/watch?v=ES32UFlPOUA
EDIT: As always, Wikipedia comes through [1]. There were species of different sizes, with tree sloths always being smaller than ground sloths [2], the giant of the article
[1] https://en.wikipedia.org/wiki/Sloth#Evolution [2] https://en.wikipedia.org/wiki/Ground_sloth
The smaller the animal, the larger skin_surface:body_mass ratio, thus higher heat loss. The smaller the animal, the shorter the intervals between feedings it can tolerate. A large-bodied animal can go for longer period of time without food, especially if equipped with slow metabolism. In contrast, smaller body and faster metabolism requires frequent feeding, but also allows an animal to out-compete slower, larger ones both in food search, and by out-breeding them.
For any given body plan, an animal can only cover distance roughly relative to its body size; the smaller animal, the harder time it will have to find sufficient food on sparse, hardy cold-climate vegetation. On the other hand, once denser, warm climate vegetation takes hold, it allows smaller herbivores to live in higher density, and with higher breeding rate.
If I remember my biology right, the more an animal has specializations for particular environment or niche, the slower it will adapt to changed circumstances, both in body build, and in behavior & seasonal migration patterns.
Last but not least, a predator population requires certain density of prey to be sustainable. Once plant food becomes abundant due to warming up, and herbivore population grows, the population of predators can be established, and cull the large bodied animals unadapted to heavy predation.
https://youtu.be/TrsaXzmqShM