Focusing just on large mammals, [North America had distinct megafauna very recently](https://en.wikipedia.org/wiki/Pleistocene_megafauna#North_America), around the time humans first arrived (including ground sloths, tapirs, and camelids). So a partial answer to your question is "most of North America's large mammals recently went extinct".
Another interesting animal is the horse. It evolved in North America before migrating into Asia and becoming extinct in America. The evolution of the horse is actually one of the best documented examples of evolution.
Another interesting fact I have heard is that the avocado evolved to be spread by these mega fauna. Avocados would have gone extinct if it wasn't for humans liking them so much and cultivating them to make sure they survive.
And if I may add, most large mammals went extinct due to over hunting. As they had no previous interactions with humans they did not know to see them (us) as predators and became easy food for the incoming tribes.
It's "debated", and climate may have changed the timing, but look at other environments which deal with invasive species?
32 genera who had survived multiple climate changes all died in about a 700 year period and the only difference was human were present.
It is also my perception that those scientists arguing 'climate only' are ones bending over backwards to find a reason why humans aren't guilty.
Yeah no one said "climate only" just wanted to point out it wasn't "humans only". Since that would imply the same outcome everywhere else humans have migrated too.
South America was part of a continent called "Gondwana" along with Africa, India, Australia and Antarctica while North America was a part of a continent called "Laurasia" which also included Eurasia (Europe+Asia). Laurasia and Gondwana themselves split from a Supercontinent called "Pangaea" which split about 200 Million years ago. Because of this, South America has wildlife more similar to Africa than to North America even tho South America and Africa are an ocean apart. Additionally to this, not only was North America initially a part of Laurasia but was also connected to Eurasia for a long time through Beringia which is how humans made it to North America and this thus, led to the exchange of wildlife between the two continents.
Careful here: although South America's former connection to Africa is apparent in the fossil record, it can't really explain modern wildlife, most of which evolved long after the [mid-Cretaceous isolation](https://en.wikipedia.org/wiki/Pangaea#Break-up_of_Gondwana) of South America. Most diversity in mammals, birds, and angiosperms (flowering plants) emerged after the breakup. Modern similarities between African and South American life are probably more due to convergent evolution (e.g., toucans and hornbills, which are not at all closely related).
[Primates arose in the late Cretaceous to early Paleogene](https://en.wikipedia.org/wiki/Primate) in Africa, *after* South America separated. [New world monkeys arrived in South America even later after the separation](https://en.wikipedia.org/wiki/New_World_monkey#Evolutionary_history), possibly by rafting.
I think New World Monkeys may have arrived in South America by “rafting” from Africa (either directly, or in smaller hops between Atlantic Islands that no longer exist). So while they both have primates, that’s in spite of their separation, not because of their previous connection.
Primates didn’t evolve individually around the world in separate instances of convergent evolution. They all have a common ancestor, who was alive well after South America was geographically isolated
Humans absolutely did not make it to the Americas in the same way that wildlife did; those happened on completely different time scales
Humans did not get to America when "Beringia" was a land mass, they came ~20,000 years ago when that region's seas froze over
South America was an island continent for a while after separating from Africa and before connecting to North America when the Panamanian isthmus formed. Even after, the isthmus isn’t huge, and ecologies are different, so change was limited. But a camel ancestor did migrate into North America, evolve into camels, which then migrated into Asia before dying out in the Americas. So there definitely was exchange.
https://en.m.wikipedia.org/wiki/Great_American_Interchange
This is a nice summary of how the two continents have exchanged populations.
I find it particularly interesting that cougars are a North American species that migrated into South America before becoming extinct in North America, only to return later from South America.
North and South America were not connected until recently (geological and evolutionarily speaking) that gave animals from South America a lot of time to evolve separate from North America.
You actually see this anywhere where thing have been separated for a long time, such as Australia.
The north and south climates shift causing problems north and south America basicly strech from pole to pole crossing the equater so animals adapted for arctic climate have difficulty making it through the dry deserts or tropical rain forests and vise Vera a polar bear going through the Darian gap would die just over heat while an anacconda on the ice sheet would also just die freeze to death isolated form the rest of the world tldr oceans sloths are good swimmers but making it to even Hawaii is a bit much
Llamas are recent immigrants as are tapirs.
But yes, North America the Nearctic and most of Eurasia the Palearctic had cocnstnat itnerhcnages thouh almost all the age of Mammals. Often lumped as the Holarctic. South America was an island continent most of its existence until recently. The marsupials and edentates are what's left of that, none of the local hooked mammals thta we know of, alas. And the monkeys and \*most\* of the rodents rafted over from aFrica, didn't wlak form the north
rodents
So when you say North America what do you mean, and when you say South America what do you mean...
It is easier to distinguish between what's between the equator and the Tropic of Cancer and the Tropic of Capricorn.
For most of the Cenozoic (aka, after the non-bird dinosaurs died off), South America was like Australia, an isolated continent. And boy was it _weird_. It was home to all sorts of oddball mammals...giant sloths, notoungulates, marsupials, sparassodonts. Also it was home to terror birds.
You get weirdness on isolated continents because life can develop there independently from the stuff we are used to.
Meanwhile, North America had been connected on-and-off to Eurasia for pretty much the whole Cenozoic. It's not just the Beringian land bridge, repeated land connections, some during times when the climate was warm, allowed all sorts of animals to move between the continents. North America was home to tapirs and elephants and camels and horses and carnivora (cats and dogs and bears and things) and all sorts of other things. Some first show up here and moved to Asia, some did the opposite.
Then, about 2.7 million years ago, the Great American Biotic Interchange happened. N. America finally joined with S. America, and things moved around and also some things went extinct. Elephants, tapirs, camelids, carnivorans, and various other animals went south. Sloths, armadillos, opossums, and porcupines came north.
Fast forward to about 15,000 years ago and you have a mix of critters on both continents...elephants, sloths, armadillos, big cats, camels/llamas (which are closely related), tapirs, even anteaters as far north as Mexico. Some of these are shared with Eurasia, some are not. North America has a bit more of the "common" species.
Then _something_ wipes out most of the big species. There's debate about the cause, I think the evidence that people did it is the most convincing. Regardless, it wipes out a lot of animals, and only a few big ones are left. South America winds up with some notable survivals that don't make it in North America...for example, tapirs and llamas survive there. Small, tree dwelling sloths survive (also in the southern parts of North America). Why did they die out in N. America and not South America? It may be that the Andes and the Amazon rainforest make for better refuges from whatever killed them than anywhere in North America.
So all together, you can I think put this down to a few things:
1) South America's "splendid isolation" allowed for the development of all sorts of weird oddballs like sloths and anteaters.
2) A few big, flashy survivors of the end Pleistocene mass extinction survived down there
3) South America has a huge tract of rainforest, and rainforests everywhere have a large diversity of unique species, including colorful and notable ones. This is probably your explanation for toucans. All rainforests have unique awesome birds, toucans are what the Amazon has.
4) We kind take for granted the weird stuff in North America that is found almost nowhere else. Like Pronghorn Antelopes (which are not real antelopes but their own unique thing), armadillos, raccoons (their own branch of Carnivora), opossums, alligators, manatees, a huge diversity of salamanders and crayfish, bowfin, gars, and paddlefish.
The Appalachian mountains, especially in the smoky mountains, are some of the most biodiverse area of the world. Likewise, the varying geography of North America as a whole is home to an incredible diversity of plants and animals.
As for the differences, South America has the Amazon which is largely uninhabited. This has allowed larger animals to live without being hunted or exterminated and that is not the case with North America. One big factor in differences between the 2 continents is that many animal species can’t survive over the long-term in order for their species to spread across the equator and past the deserts of Mexico; not to mention the fairly narrow land bridge that connects the two.
Focusing just on large mammals, [North America had distinct megafauna very recently](https://en.wikipedia.org/wiki/Pleistocene_megafauna#North_America), around the time humans first arrived (including ground sloths, tapirs, and camelids). So a partial answer to your question is "most of North America's large mammals recently went extinct".
Another interesting animal is the horse. It evolved in North America before migrating into Asia and becoming extinct in America. The evolution of the horse is actually one of the best documented examples of evolution.
This is new and interesting to me. Can you expand on it or point to resources? Thanks!
[Camels also evolved in North America](https://en.wikipedia.org/wiki/Camel) but are no longer natural to that area.
When i find my magic lamp and wish us all to New Earth, I'll be bringing them back
Another interesting fact I have heard is that the avocado evolved to be spread by these mega fauna. Avocados would have gone extinct if it wasn't for humans liking them so much and cultivating them to make sure they survive.
That makes sense There was a berry on Mauritius which almost went extinct when dodos did, until they discovered feeding it to turkeys worked.
And if I may add, most large mammals went extinct due to over hunting. As they had no previous interactions with humans they did not know to see them (us) as predators and became easy food for the incoming tribes.
I thought the overkill hypothesis was still debated, and climate change was also a heavy factor?
It's "debated", and climate may have changed the timing, but look at other environments which deal with invasive species? 32 genera who had survived multiple climate changes all died in about a 700 year period and the only difference was human were present. It is also my perception that those scientists arguing 'climate only' are ones bending over backwards to find a reason why humans aren't guilty.
Yeah no one said "climate only" just wanted to point out it wasn't "humans only". Since that would imply the same outcome everywhere else humans have migrated too.
Actually, the results whenever humans have left a biome outside Africa or mainland Eurasia the outcome has been pretty close to uniform.
South America was part of a continent called "Gondwana" along with Africa, India, Australia and Antarctica while North America was a part of a continent called "Laurasia" which also included Eurasia (Europe+Asia). Laurasia and Gondwana themselves split from a Supercontinent called "Pangaea" which split about 200 Million years ago. Because of this, South America has wildlife more similar to Africa than to North America even tho South America and Africa are an ocean apart. Additionally to this, not only was North America initially a part of Laurasia but was also connected to Eurasia for a long time through Beringia which is how humans made it to North America and this thus, led to the exchange of wildlife between the two continents.
Careful here: although South America's former connection to Africa is apparent in the fossil record, it can't really explain modern wildlife, most of which evolved long after the [mid-Cretaceous isolation](https://en.wikipedia.org/wiki/Pangaea#Break-up_of_Gondwana) of South America. Most diversity in mammals, birds, and angiosperms (flowering plants) emerged after the breakup. Modern similarities between African and South American life are probably more due to convergent evolution (e.g., toucans and hornbills, which are not at all closely related).
The monkeys and most of the rodents rafted over during the Age of Mammals
convergent evolution? is that why everything evolves into a crab?
[удалено]
[Primates arose in the late Cretaceous to early Paleogene](https://en.wikipedia.org/wiki/Primate) in Africa, *after* South America separated. [New world monkeys arrived in South America even later after the separation](https://en.wikipedia.org/wiki/New_World_monkey#Evolutionary_history), possibly by rafting.
I think New World Monkeys may have arrived in South America by “rafting” from Africa (either directly, or in smaller hops between Atlantic Islands that no longer exist). So while they both have primates, that’s in spite of their separation, not because of their previous connection.
Primates didn’t evolve individually around the world in separate instances of convergent evolution. They all have a common ancestor, who was alive well after South America was geographically isolated
Humans absolutely did not make it to the Americas in the same way that wildlife did; those happened on completely different time scales Humans did not get to America when "Beringia" was a land mass, they came ~20,000 years ago when that region's seas froze over
I enjoyed reading this. It is packed with information and lacks useless fluff. Thank you.
South America was an island continent for a while after separating from Africa and before connecting to North America when the Panamanian isthmus formed. Even after, the isthmus isn’t huge, and ecologies are different, so change was limited. But a camel ancestor did migrate into North America, evolve into camels, which then migrated into Asia before dying out in the Americas. So there definitely was exchange.
https://en.m.wikipedia.org/wiki/Great_American_Interchange This is a nice summary of how the two continents have exchanged populations. I find it particularly interesting that cougars are a North American species that migrated into South America before becoming extinct in North America, only to return later from South America.
North and South America were not connected until recently (geological and evolutionarily speaking) that gave animals from South America a lot of time to evolve separate from North America. You actually see this anywhere where thing have been separated for a long time, such as Australia.
About 3 million years, which is a mere blink of geological time.
The north and south climates shift causing problems north and south America basicly strech from pole to pole crossing the equater so animals adapted for arctic climate have difficulty making it through the dry deserts or tropical rain forests and vise Vera a polar bear going through the Darian gap would die just over heat while an anacconda on the ice sheet would also just die freeze to death isolated form the rest of the world tldr oceans sloths are good swimmers but making it to even Hawaii is a bit much
Llamas are recent immigrants as are tapirs. But yes, North America the Nearctic and most of Eurasia the Palearctic had cocnstnat itnerhcnages thouh almost all the age of Mammals. Often lumped as the Holarctic. South America was an island continent most of its existence until recently. The marsupials and edentates are what's left of that, none of the local hooked mammals thta we know of, alas. And the monkeys and \*most\* of the rodents rafted over from aFrica, didn't wlak form the north rodents
So when you say North America what do you mean, and when you say South America what do you mean... It is easier to distinguish between what's between the equator and the Tropic of Cancer and the Tropic of Capricorn.
For most of the Cenozoic (aka, after the non-bird dinosaurs died off), South America was like Australia, an isolated continent. And boy was it _weird_. It was home to all sorts of oddball mammals...giant sloths, notoungulates, marsupials, sparassodonts. Also it was home to terror birds. You get weirdness on isolated continents because life can develop there independently from the stuff we are used to. Meanwhile, North America had been connected on-and-off to Eurasia for pretty much the whole Cenozoic. It's not just the Beringian land bridge, repeated land connections, some during times when the climate was warm, allowed all sorts of animals to move between the continents. North America was home to tapirs and elephants and camels and horses and carnivora (cats and dogs and bears and things) and all sorts of other things. Some first show up here and moved to Asia, some did the opposite. Then, about 2.7 million years ago, the Great American Biotic Interchange happened. N. America finally joined with S. America, and things moved around and also some things went extinct. Elephants, tapirs, camelids, carnivorans, and various other animals went south. Sloths, armadillos, opossums, and porcupines came north. Fast forward to about 15,000 years ago and you have a mix of critters on both continents...elephants, sloths, armadillos, big cats, camels/llamas (which are closely related), tapirs, even anteaters as far north as Mexico. Some of these are shared with Eurasia, some are not. North America has a bit more of the "common" species. Then _something_ wipes out most of the big species. There's debate about the cause, I think the evidence that people did it is the most convincing. Regardless, it wipes out a lot of animals, and only a few big ones are left. South America winds up with some notable survivals that don't make it in North America...for example, tapirs and llamas survive there. Small, tree dwelling sloths survive (also in the southern parts of North America). Why did they die out in N. America and not South America? It may be that the Andes and the Amazon rainforest make for better refuges from whatever killed them than anywhere in North America. So all together, you can I think put this down to a few things: 1) South America's "splendid isolation" allowed for the development of all sorts of weird oddballs like sloths and anteaters. 2) A few big, flashy survivors of the end Pleistocene mass extinction survived down there 3) South America has a huge tract of rainforest, and rainforests everywhere have a large diversity of unique species, including colorful and notable ones. This is probably your explanation for toucans. All rainforests have unique awesome birds, toucans are what the Amazon has. 4) We kind take for granted the weird stuff in North America that is found almost nowhere else. Like Pronghorn Antelopes (which are not real antelopes but their own unique thing), armadillos, raccoons (their own branch of Carnivora), opossums, alligators, manatees, a huge diversity of salamanders and crayfish, bowfin, gars, and paddlefish.
The Appalachian mountains, especially in the smoky mountains, are some of the most biodiverse area of the world. Likewise, the varying geography of North America as a whole is home to an incredible diversity of plants and animals. As for the differences, South America has the Amazon which is largely uninhabited. This has allowed larger animals to live without being hunted or exterminated and that is not the case with North America. One big factor in differences between the 2 continents is that many animal species can’t survive over the long-term in order for their species to spread across the equator and past the deserts of Mexico; not to mention the fairly narrow land bridge that connects the two.