We're lucky to be living in amazing times where the largest creatures that have ever lived on this planet are alive...and their explosion is size is just 3 million years old.
> Another hypothesis known as the Brownian motion model of evolution posits that animals get big and small at random. In this scenario, the descendants of an animal would be both larger and smaller than their ancestor, but this didn’t fit with the data either, since whales got only bigger.
The hypothesis only applies to large numbers of species. Of course the largest animals only got larger; otherwise they wouldn't be the largest. If every species only got larger, then the model would be false, but some species get larger and some get smaller.
In this case, the article does posits an interesting climactic and fossil-record history of a recent growth spurt that's not purely random Brownian motion. But in general, you cannot look at an outlier and infer whether a general rule is true or false.
Animals do tend to get big and smaller at random. Whales appear to have been selected to be bigger. Why is always an interesting question when it comes to evolution. The answer is of course giant undiscovered subaquatic predators.
Which must obviously raise the question: Is the coincidence a coincidence? Which it might well be, but how infinitely more exciting if the giants and we were somehow molded from the same set of circumstances. I am not really qualified to judge whether the article implies such a thing.
I imagine we would have a giant fin along our spine and would be required to sleep in the sun for 10 hours per day and 8 hours per night to be able to function in the rest 6 hours. But on the other hand we would be much smarter with bigger brain in those 6 hours.
The article does not imply such a thing. It might be related, it might not be, but there's been no studies about that, and the paper referenced in the article was published this week.
For comparison the largest blue whales are up to ~180 tons and 30 meters long, and the largest elephants are ~12 tons and 6 meters long (some prehistoric elephants may have gotten up to 22 tons).
Probably not. Some marine invertebrates are much longer and being colonial a coral born from a single egg has unlimited growth, so could be theoretically larger than a whale and more massive.
All macroscopic life on Earth has existed for only about 600 million years, since the Cambrian Explosion.
Significant land life, about 350 million years.
Over 4.5 billion years, less than 15% of the total duration of the planet.
For most of Earth's existance, if you'd come searching for signs of life, you'd have found little but slime and bacterial stew in oceans and ponds. If that.
>"You have the privilege of sharing the planet with the largest animal that ever lived on Earth."
We've returned the favor by killing 90% of them.
>The IUCN estimates that there are probably between 10,000 and 25,000 blue whales worldwide today. Before whaling, the largest population was in the Antarctic, numbering approximately 239,000 (range 202,000 to 311,000).
At first this was going to be one of those tedious meta-pedantry posts. But then I realized I was about to post one, and remembered meta-pedantry is a thing, so now it's going to be a meta-meta-pedantry post.
Basically, it's surprisingly common to point out, in a fun-loving-meant-to-be-helpful way, someone's minor error of style or grammar, and in the process make a different error of style or grammar yourself.
That, in turn, spawns a slew of "na, na, stones in glass houses, you're not perfect either" posts. Which are tedious, and often dramatically less principal-of-charity laden then the first instance of pedantry.
I'm not sure where this comes from, precisely, it may just be that people reading a pedantic post are less charitable in their reading than than they would be on an on-point substantial post.
Anyway. All that is just preamble to "perhaps you meant 'who'? 'Whom' is functioning as a subject, not direct object in your sentence (the reverse of what's grammatically required)"
> Pre-exploitation population estimate of 239,000 (95% interval 202,000–311,000).
> Estimated 1996 population size, 1,700 (860–2,900)
Don't use three significant figures when your confidence interval spans 50% of your estimate. "200,000 to 300,000" would more clearly express the data.
And be honest about accuracy: if modern satellite, aircraft, and naval technology can't pin the 1996 value down more tightly than "half this number to double it", you can hardly say with a straight face that your confidence interval on the 1800s data is "minus 15% to plus 25%".
Humankind has transformed in the last century-and-a-half: a good chunk of our species is now taller than it's ever been.
Over the last 150 years the average human height has gone up in industrialized countries by up to 10 centimetres. And gains of up to 19 centimetres for Dutch men and woman.
Sure, but that's not evolution at work, that's just chronic malnutrition finally being solved.
Pre-agriculture humans were about the same size (apparently, we can tell by measurements of the pelvic bone of ancient skeletons). We shrunk after we switched to agriculture, which basically started out as a steady supply of nutritionally inferior food (which could be indirect evidence that we mainly switched because we ran out of easy-to-forage healthier food). So a typical example of a 'good enough' solution, really.
> And gains of up to 19 centimetres for Dutch men and women.
I am a 6' Netherlander (among the shortest men in my family). I just traveled to Shanghai and met a lot of very short Chinese people - but I was surprised to see that there seemed to be a small population of some young men who were as tall or taller than me.
When I asked about these tall Chinese of a native, she explained that they were from northern China, and that they have a harsher climate and eat more fish and protein than locals. Many of the locals grew up subsistence farming under Mao, mostly eating rice, and she explained that the weak nutrition of the resulting diet resulted in less growth.
This is, of course, anecdotal. But in comparison to Dutch height gain, I haven't heard of a similar change in Dutch nutrition or health, at least not relative to peer countries.
For a large part of history human height has been limited by nutrition. This is why the United States was the tallest country in the world at the beginning of the 20th century.
Once everyone is everyone is fed the genetic differences become apparent.
There are plenty examples of this. For instance, the Normans who invaded England were nearly six feet tall. However, by the mid-17th century the average man in Europe was something like 5'3-5'6.
My great-grandfather was 5'3, and my great-grandmother was 4'11. They grew up during a famine in Hungary. My grandmother was 5'8, my dad was 5'11", and I'm 6'3".
Of course my mom is half dutch, and her mom was 100% dutch and was 6'1", which is huge considering she was born in 1913. So I definitely get some of my height from that side of my family.
There could very well have been something bigger but never left fossils. I mean fossil creation itself is sort of a miracle. Combined with such an animal really bound to living in the ocean, it would be very difficult for a whale the size of a blue whale to
1: meet the conditions to be fossillized
2: survive millions of years
3: discovered at the bottom of the ocean
An astronomer, a physicist and a mathematician are on a train in Scotland. The astronomer looks out of the window, sees a black sheep standing in a field, and remarks, "How odd. Scottish sheep are black." "No, no, no!" says the physicist. "Only some Scottish sheep are black." The mathematician rolls his eyes at his companions' muddled thinking and says, "In Scotland, there is at least one field, containing at least one sheep, at least one side of which appears black from here."
On top of that, oceanic crust is all quite new, geologically speaking. Even if something large and oceanic did manage to fossilize, unless it was also in a shallow interior sea, whatever rock it fossilized in has been subducted and destroyed past a few hundred million years.
it's not unfounded. there's direct supporting evidence. and they're not really absolute. it's blatantly obvious that the "that we know about" is implicit.
It seems like humans could also cause them to be bigger. Food distribution became more concentrated over time. If humans impact the world in a way that magnifies this power law distribution of food, we could end up with even bigger whales, right?
The reciprocal of this is that here in Oklahoma we've got animal breeders turning saltwater runoff from reinjection wells into mini seas so as they claim... to breed tiny pet whales. The goal is to have teacup size whales that fit into purses in a hundred years or so. Idk internet cuteness combined with the desire to eat them in a sustained way or something, I guess. I think the whole thing is crazy and unethical.
Or so you claim. There’s enough family business in Europe or Japan that existed for centuries or even a thousand years that for them a hundred year business plan can make sense.
longevity has nothIng to do with havinv hundred years plans. Most businesses hardly a vision beyond 20 years from now, because the longer you try to project the more preposterous your assumptions are.
According to climate models, much arable farmland will be destroyed by climate change. There will be increasing pressure for protein and calories from all sources. Perhaps whales could be domesticated. If not, rapid changes in ocean energy absorption and chemistry threaten the entire food chain.
Another long-term consideration is industrial protein manufacturing to skip the risks and mess of CAFOs in Brazil and Texas, and fish feeding operations like the horrible fish farms throughout the world from Thailand to Norway. It maybe possible to greatly reduce the risk of a global pandemic if animals and people aren't kept in excesssively close proximity.
Megafauna doesn't have much hope in the Holocene extinction event. One only need to look at the odd survival of avocados which were likely to have died out as humans likely killed their primary seed distribution omni or herbivores. There is little causal data, but it's a contributing factor.
Holocene extinction will likely continue until the entire planet collapses, humans die out or kill everything that isn't or cannot be domesticated. There is simply too much energy already absorbed forcing climate change to be reversed even by redirecting all GDP into geoengineering... Greenland and Antarctica will melt over a thousand years, sea levels will rise 100 m (~300 ft).
I watched a program once that said that one of the reasons they are so big is to allow them to communicate over large distances. Is there any truth in that? It was a kids program though - probably octonauts
Gp's claim does not imply teleology of any kind; it's entirely plausible in terms of increasingly larger animals being selected for their hability to communicate over increasingly larger distances. Finding mates in a larger volume of ocean comes to mind.
So the blue whale got big to eat more krill- does that mean that there's no other animal than the blue whale that can eat as much krill as a blue whale?
In that case, what would happen to the krill if the blue whale went extinct? Would its numbers grow uncontrolled until it took over the oceans? Or is other predation enough to keep its numbers down?
What is not mentioned in the article is the reason big animals exist: efficiency. The physics are simple: assume animals are ball-shaped (true to within a factor 2 for mammals). That means the amount of filling grows with the third power of the radius. The "skin", or outer boundary only grows with the second power.
"Skin" is how an animal loses power (by far the biggest power draw inside mammals is keeping the body warm. Obviously in water this is an even bigger problem). "Filling" is how an animal generates power.
That means that smaller animals cannot hope to match the whales in efficiency: for sustaining the same biomass, they need to keep a bigger "skin" warm (add all the skin of all individuals together).
Now when does this matter ? Obviously this would matter a lot in terms of scarcity, at which point it would be much easier for whales to survive than smaller fish. When there is richness of food, smaller is better, as you can move faster and "eat" the available energy faster. However if smaller animals do this to the point that food becomes scarce, they've just screwed themselves.
So you see what happens : the longer the biosphere goes without a major disaster, the bigger animals get (and plants, for that matter). The advantage of being the first mover, where you can be small and still win, disappears, and the advantage of efficiency grows and grows. So when food became scarce, whales, the biggest animals that had the easiest time surviving at that point, became even bigger. That made the difference between different whale species.
This framework allows answering your question: no, if whales went extinct fish would increase in numbers (slightly, in the sense that it'd be less than the biomass of the whales that disappeared). There isn't enough predation to replace the whales at the moment, but that would be very quickly rectified if something happened to them.
The real reason krill is increasing is the slight increase of co2 caused by humans (krill eat plankton, as do most whales). It's tiny when measured compared to total volume, but if you look at it in relative terms co2 has increased quite a bit (amount now vs amount 100 years ago). In reality the plant growth in the world is hampered significantly by the amount of available co2, and the fact that plants use it to store energy, a part of which gets buried and is lost to the depths (literally in the case of krill).
The critical part is not more food, but very unequal distribution of food. Quoting: "..from the time of the dinosaurs to about 3 million years ago, nutrients were evenly distributed across the ocean. But then there was a transition, in which dense aggregations of nutrients could be found along certain coastlines, while vast parts of the open ocean became virtual marine deserts."
maybe it does, too, but maybe that leads to higher selection preassure where being huge is the deciding advantage - there are different lineages evolving different traits, so the population just doesn't appear increased because it's highly heterogenous.
> Hungry whales accelerate into this swarm with their enormous mouths open, eventually filtering out the water and swallowing the krill. Using this technique, the biggest whales can ingest half a million calories in a single bite.
How many of y'all know that Crocodiles can grow really big because they get bigger throughout their life? And that crocodiles will not die "unless" they are deprived of food or get sick? Both true facts.
