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I like to bring this up, but 8,000 years ago half of North America was under ice. That means that every living creature in that region didn’t exist. Every creat

I like to bring this up, but 8,000 years ago half of North America was under ice. That means that every living creature in that region didn’t exist. Every creature unique to those regions came about in the last 8,000 years. 1. I think evolution happens much faster than people realize 2. Extinctions happen more quickly than people realize 3. Humans likely were the cause of many extinctions through pollution and cultivation. But other animals and plants are currently filling the niche and containing to expand. I would really like to understand the distribution of species over the last 10k, 100k, 250k, 1m years. We simply don’t have great data so it’s really hard to say. What I can say, is that there’s a ton of life. Life doesn’t appear to have diminished much on a whole. Which is comforting, at the very least.

Maursault 5y ago
> Life doesn’t appear to have diminished much on a whole. There are a lot more humans now, and a lot more cows, sheep and hogs. There's much less of everything else, from the bottom on up. I think where it is easy to see is in the drastic decline in small and large mammals, other than humans, cows, sheep and hogs. Once you see that, maybe you'll notice, just in your own lifetime, the massive decline in bird species and populations. Maybe you'll notice when you drive around at night in the Summer you no longer have a windshield covered in dead bugs. I haven't see a real frog in years. Unless you're satisfied with merely diverse species of bacteria and other simple life forms for the next X billons of years, you should be startled at how astoundingly quickly Earth's amazing diversity of life has declined from whatever it's most recent peak was before the development of civilization, or before the Babylonians, before the Greeks, before the Romans, before the Industrial Revolution, and before the Chemical Revolution. Don't you ever wonder just how many whales there were before the first whalers? Or how many tuna or salmon there once were? Reports from Colonial times on bird populations aren't very specific, but at certain times of years, the number of geese alone in Virginia used to darken the sky. They didn't just shoot down one goose at a time, they used giant guns that took hundreds at a time. Maybe we don't do it with big guns, but we are basically poisoning everything on the planet to death. So maybe the amount of biomass stays the same, but who wants a planet of poison goo?
kuhewa 5y ago
The last time half of North America was under ice was 20kya, 8kya was relatively warm with just a bit of ice that hadn't melted yet in the northeast of Canada. The species that entered those areas would have done so during climate-driven redistributions from the south as entire plant and animal communities moved north to fill new available habitat, and while there would have been some local adaptation, it isn't like they all evolved from vastly different ancestors in 20k years. > But other animals and plants are currently filling the niche and containing to expand. Sort of. For example, the main thing that has filled the niche of predator of grazers like deer across eastern North America is probably the automobile. In terms of biomass, yes there's a lot of domestic animals. But in terms of functional diversity, there has been a great decline. Just think of the difference between prarie and a crop monoculture. The fewer species in each guild that interact to form the ecosystem, the less resilience overall. Despite large amounts of biomass, the loss of biodiversity is undeniably an issue.
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Maursault 5y ago

> Life doesn’t appear to have diminished much on a whole. There are a lot more humans now, and a lot more cows, sheep and hogs. There's much less of everything else, from the bottom on up. I think where it is easy to see is in the drastic decline in small and large mammals, other than humans, cows, sheep and hogs. Once you see that, maybe you'll notice, just in your own lifetime, the massive decline in bird species and populations. Maybe you'll notice when you drive around at night in the Summer you no longer have a windshield covered in dead bugs. I haven't see a real frog in years. Unless you're satisfied with merely diverse species of bacteria and other simple life forms for the next X billons of years, you should be startled at how astoundingly quickly Earth's amazing diversity of life has declined from whatever it's most recent peak was before the development of civilization, or before the Babylonians, before the Greeks, before the Romans, before the Industrial Revolution, and before the Chemical Revolution. Don't you ever wonder just how many whales there were before the first whalers? Or how many tuna or salmon there once were? Reports from Colonial times on bird populations aren't very specific, but at certain times of years, the number of geese alone in Virginia used to darken the sky. They didn't just shoot down one goose at a time, they used giant guns that took hundreds at a time. Maybe we don't do it with big guns, but we are basically poisoning everything on the planet to death. So maybe the amount of biomass stays the same, but who wants a planet of poison goo?

kuhewa 5y ago

The last time half of North America was under ice was 20kya, 8kya was relatively warm with just a bit of ice that hadn't melted yet in the northeast of Canada. The species that entered those areas would have done so during climate-driven redistributions from the south as entire plant and animal communities moved north to fill new available habitat, and while there would have been some local adaptation, it isn't like they all evolved from vastly different ancestors in 20k years. > But other animals and plants are currently filling the niche and containing to expand. Sort of. For example, the main thing that has filled the niche of predator of grazers like deer across eastern North America is probably the automobile. In terms of biomass, yes there's a lot of domestic animals. But in terms of functional diversity, there has been a great decline. Just think of the difference between prarie and a crop monoculture. The fewer species in each guild that interact to form the ecosystem, the less resilience overall. Despite large amounts of biomass, the loss of biodiversity is undeniably an issue.

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