| > that's fair, but they'd just kinda sit at a half step between herbivore and predator no it doesn't. We are not predators and are not herbivores. swines are not herbivore but not predators. But in fairness it's not very common, the real point is that if we look at the data, mammals are mostly carnivores, 63% of them is, but that doesn't imply being a predator. The other point is that the cycle is not predator eats herbivore which eats plants. That is a mammal-centric view that completely removes from the equation the majority of lifeforms on Earth, 'cause mammals are a minority of the species in nature. Many predators also feed from other lesser predators, example: snakes. Snakes don't eat herbivores, they eat small rodents that usually eat other smaller animals. Truth is the cycle is a lot more about bacteria that eats a substance (that probably comes from the putrefaction of some dead animal) that creates some other substance that other bacteria live on and they too produce something that simple life forms use to produce energy and after many of these steps, maybe there's some plant or fungi that consumes those nutrients in the soil and then "do you have time to talk about our lords and saviors the insects, the 900 thousands species of them?" Oceans are not absolutely more complex than terrestrial life and why should they be? Life on Earth evolved over hundreds of millions of years, it makes sense that it adapted to every ecosystem the Earth has to offer. > marine food chains are longer a bit longer doesn't mean what the original comments was about. The study also says that the chain is longer in the lowest segment of the chain where the size is microscopic. So when you arrive at the zooplankton level, you are already at very large animal eats helpless food (plants or soup of proteins) and then get eaten by a predator or it's too big to be annoyed by anybody (elephants and whales, for example) |
> We are not predators and are not herbivores.
> swines are not herbivore but not predators.
Yet.. both of those examples are exactly that, omnivores, and both are also sometimes functionally predators.
And it absolutely follows that you can put an omnivore at half trophic step between a primary consumer (i.e. a predator of herbivores) and an herbivore. The way trophic levels are described are in fractional numbers of the mean trophic level of what you eat. Predator is a functional group rather than a descriptor trophic level, but when it comes down to it very few animals are pure functional specialists and very rarely does one sit perfectly at a given trophic level - to use your snakes example, they absolutely eat herbivores sometimes even if they are usually eating things that eat animals. Cows consume the occasional insect, I've seen algae-specialist green sea turtles opportunistically eat dead fish, and some shark species eat a non-negligible amount of grass. But I'm going to continue calling sea turtles grazing herbivores and sharks consumers and predators, because that is true to a first approximation.
Regarding ecosystem complexity, I don't believe I mentioned it other than length of trophic chains. However I'll point out that this
> Oceans are not absolutely more complex than terrestrial life and why should they be? Life on Earth evolved over hundreds of millions of years, it makes sense that it adapted to every ecosystem the Earth has to offer.
Doesn't follow. Sure, life evolved everywhere, speciation occured and niches have been pretty well filled. That doesn't mean ecosystem complexity is the same everywhere, there are a number of identified drivers of species richness and functional diversity (e.g. latitude) and decades of theory to try to explain why, because a rainforest is more complex than a sweetgrass prarie, and a coral reef is too. A rainforest probably beats a lot of marine ecosystems, say a soft sediment continental shelf in terms of complexity due to greater species richness, simply more connections between species at many levels and lots of niche partitioning.
Can't say I understand your point about food chains being longer due to microscopic primary producers. That is still the energetic pathway that feeds into the rest of the ecosystem.
> a bit longer doesn't mean what the original comments was about.
My reading of that comment was exactly that, that marine food chains are longer. That commenter exaggerated a bit the degree to which that is true. That study I linked provides some plausible mechanisms of why that may be.