Three questions about the largest (ever) living organism

Factual Questions
1

1 On a recent visit to New York’s Museum of Natural History I learned that some or all of the hugest dinosaurs lived some of their lives in water. This was necessary because the buoyancy of water was required for their great weight. (As for the blue whale).

Was this true of all of the largest dinosaurs?

If so, Is the elephant the largest animal that (ever) lived entirely on land?

  1. According to a number of sources, the largest living organism (ever) is a mushroom fungus in the American northwest.
    No doubt this is correct using the definition of largest organism used: “It’s one set of genetically identical cells that are in communication with one another that have a sort of common purpose or at least can coordinate themselves to do something,”.

However: Am I correct in thinking that, if you cut this mushroom in half (or cut off a piece of it) and replanted it, another mushroom would grow? If so, and you added to the definition of largest organism the preclusion of this characteristic (as I would), then the mushroom would not be the largest organism. (If you cut a dinosaur or a blue whale in half, you would not get another dinosaur or blue whale.)

  1. By my definition, would a sequoia be like the mushroom/blue whale?
2

A comment rather than an answer to your first point.

While there was a well-established belief last century that the largest dinosaurs [the sauropods] were too big to function on land, and so bobbed around in the water, a range of evidence now confirms that this was not the case. The biggest dinosaurs were land-based. Maybe they waded across a stream to get to the other side [in the absence of Cretaceous roads], but they were not temporarily aquatic or amphibian in the way you describe.

The bigger sauropods were all bigger than elephants, and were the largest animals to live entirely on land.

I’m intrigued as to what you saw and how you interpreted it as the current scientific position.

3

Just a further clarification, there is support for spinosaurus being at least partly aquatic, and the largest specimens peg out at similar in overall size to the biggest tyrannosaurs and carcharodonts, although these were much heftier. They were all dwarfed by bigger sauropods.

Spinosaurs and other dinosaurs graphic

Bit dated but the graphic is great

4

We get bogged down into an issue of semantics, as we often do here on the Straight Dope, when we try to to define biggest/mostest whatever. Life is so much easier, when all we had was books/nature programs: the producer said this was the biggest, and you could yell at the screen if you disagreed, but that had little effect.

For number 3, plants, animals and fungi are different “Kingdoms” of life, as we like to define them. You notice right away, fungi are colonial organisms, and animals are organized as cells, then tissues, then organs, then organ systems and finally into organisms. You can cut a colony of fungi, you can’t cut a blue whale into pieces that are functional subsets of the whole.

Plant cells, tissues and systems are little different from both. We can, in some cases, split a plant into two and have it repair the damage and grow as two. They do this on their own, its how some plants propagate.

But you can Wikpedia each term I’ve mentioned, until you learn all the botany and high school science you need to understand your question satisfactorily for your curiosity. But there won’t be a completely definitive answer – we made up all of these terms, we redefine them constantly, no gets it right all the time forever.

5

Was that exhibit sponsored by the Dodge DeSoto and the DuMont Television Network? I’m shocked that the museum would still be displaying such utterly outdated information. Not only did the hugest dinosaurs live on land, but there is evidence that they had migratory routes of walking hundreds or thousands of miles across that land every year.

6

The tree issue is interesting.

There’s a mammoth clonal group of aspen trees that might qualify as the world’s largest organism by weight.

Is that one organism or not? If not, where do you draw the line. What about a bush with many stalks coming out of the ground? Etc.

It’s not just in terms of size. The “age” of some ancient trees is questionable since the current living part sort of grows on the side of the oldest parts. Sometimes the living parts are … parts. Two or more relatively separate pieces. Is this the “same” tree or a sucker off the original?

People like nice neat definitions. That’s not always possible.

7

BTW, even discounting the sauropods, the indricothere was much bigger than any modern elephants (and around the same size as the largest extinct elephant.)

8

But there are animals that will do this, too. Sponges can reproduce through fragmentation, star fish will do it if you chop them up, nematodes (I think), and surely others.

9

And if you don’t accept an organism that can be split is a single organism, then what does count as a single organism of that species?

10

“And if you don’t accept an organism that can be split is a single organism, then what does count as a single organism of that species?”

In such a case, the smallest part that can be split and live as additional members of the species is the single organism of that species.

A dinosaur or an elephant or a whale can not be split in two to make two organisms and are therefore much larger than a single organism of the huge mushroom.

11

The concept that the entire earth (or all the life it sustains) can be viewed as a sort of organism - is that PURE metaphor, or is there a grain of truth in it?

12

All of the life on Earth is presumed to be descended from the same first organism so you could define things in such a way that all life is just an extension of that organism’s life cycle…it’s not a definition that is of any use though.

13

[Not a biologist, please take this with a 50 lbs sack of salt …]

<nitpick> The mushroom is the fruiting body of the fungus … like the flower of plants … take an old dried up marigold flower and bury it in the ground, new marigold plants will grow … so we’re not just cutting a blue whale in half, we’re cutting out her fertilized eggs and incubating them so they can continue to develop …</nitpick>

Marigolds, whales and wolves are all higher forms of life, and individuals within these species have unique DNA … so that’s a simple way to define what an individual is … lower plants, fungi; it’s not always as this clear … a one celled algae plant simply divides in half, the daughter cells are genetically identical … do we have a larger algae plant or do we have two algae plants? …

I believe the fungus in the Pacific Northwest is thought to have started with a single spore, and has spread out from there … and this is considered a single individual fungus as every part of it is connected to every other part … but as noted above, this is also true for Aspen trees … the difference being only the definition of “individual” between mycologists and botanists …

We also have the New Age Gaia Hypothesis* which gives the whole of Earth as a living being … then we need to be looking at some of the galactic super-clusters as the largest living thing … shoot, or the universe in total … why not, it’s New Age-ism, anything goes …

Let’s throw a jelly fish in the mix … is this a single organism, or is it a colony of individual zooids? … the line is blurry here, if we regard the jelly fish as a single organism, then why not ant colonies some of which can get insanely large … what about humans, are y’all individuals or just zooids yourselves? …

I’m afraid that with the amazing diversity of life, we can’t use hard and fast definitions … we still have trouble defining what is alive and what is not, viruses do not have their own DNA/RNA but hack another organism’s code for their filthy purposes … I know viruses reproduce but then again take a hammer to a rock and, see, now you have ten rocks … that doesn’t make rocks living things now does it? …

  • = There is something I like calling the Sound Scientific Gaia Hypothesis, although it’s more of a theory from which hypothesium may be derived … “geology effects biology and biology effects geology” …
14

Viruses do have their own DNA or RNA (though never, to my knowledge, both). What they lack is all of the infrastructure to do anything with that DNA or RNA.

15

My first encyclopedia as a kid that was published in the 40s or earlier showed the large dinosaurs living in water. The long necks were an indication they had to raise their heads above the water to breathe. This concept was used in the original King Kong movie. I am surprised it would be presented at all now as anything but to demonstrate the lack of understanding of dinosaurs from a much earlier time.

16

Well, the proponents of the Gaia Hypothesis see it sort of that way, and take it to the next level.

17

How is the age of a tree determined? Sure, there are tree rings, but isn’t the wood of a tree considered dead, while the bark, leaves, stems, roots, etc. are considered alive? Are we counting only the age of the “live” part of the tree?

18

Well retroviruses have RNA and a reverse transcriptase to turn it into DNA so while they’re replicating you’ll find both. Not both in the capsid though

19

That’s just the kind of thing I love to check out on road trips. Next time I’m in the area I will definitely go see it. Looks like there’s a campground right on the edge of the grove.

20

Nope, all the rings are counted, dead or alive.