Scientists uncover the ancient origins of baobab trees | Hacker News Reader

Scientists uncover the ancient origins of baobab trees

smithsonianmag.com

67 pointsNoRagrets20 comments

TLDR: They originated in Madagascar and two species traveled along ocean currents to reach mainland Africa and NW Australia. This differs from the prevailing thought that they originated on mainland Africa.

What I found surprising was that baobab fruit exhibited adaptations that could allow them to travel long distances on the ocean and still be viable. I thought such feats were only possible by highly specialized plants like coconut and mangroves

> two species traveled along ocean currents

Oh interesting! I just started reading The Monkey's Voyage: How Improbable Journeys Shaped the History of Life by Alan de Queiroz and I think I'm going to enjoy it as much as The Song of the Dodo many years prior. Historical biogeography is very fascinating!

Anything placed in the same realm as Song of the Dodo is a recommendation I take to heart. Thanks!

>I thought such feats were only possible by highly specialized plants like coconut and mangroves

How are those more specialized than baobabs or other fruit/seeds in general?

Oceanic transport is a viable dispersal mechanic for lots of plants. Another family you might not know that uses it are the squashes/gourds.

Whole pumpkins floating over the sea, or just the seeds? What makes them suitable for or likely to be transported across the ocean?

Bottle gourds in particular are known to have been dispersed across the ocean, probably by simply floating.

It seems like the main evidence supporting this is genetic research. That doesn't necessarily mean it's evolved to disperse in this way. It could have just been a freak accident.

In fact, if the bottle gourd did specifically evolve to disperse in this way, wouldn't we expect to see more examples of populations in the new world rather than just the one?

Coconuts on the other hand are found all along coasts from Indonesia to Africa to the New World. It's clear that they're reproductive strategy is geared towards dispersing in this way.

I think it's a stretch to say gourds also have this strategy just because it happened once

It's always more than a stretch to say that evolution has any strategy.

All of evolution is merely freak accidents. Some advantageous, some not. But never any intent.

> Coconuts on the other hand are found all along coasts from Indonesia to Africa to the New World. It's clear that they're reproductive strategy is geared towards dispersing in this way.

It never occurred to me to wonder how palm trees came to be found on remote islands, but something about the idea of coconuts bobbing on ocean currents is unexpectedly satisfying.

Hmm you'll have to be more specific. The gourd family has nearly 11k described species which contain everything from zucchini to watermelon to many desert-adapted plants. Surely ocean dispersal is not widespread among the family

The Nature article is here https://www.nature.com/articles/s41586-024-07447-4

Somebody (I don't remember who) suggested that Australian Boabab trees were potential evidence of the direct population of Australia from Africa by a pre-Aboriginal people, based on the idea that the fruit of the Boabab tree would be an excellent food source for a long cross-ocean crossing, as well as supposed "African" characteristics in the Kimberley petrographs found in the same area as the trees. The theory is fringe-science at best (and I believe slightly offensive to Aboriginals) but I've been curious about the origin of the trees since coming across the theory. I skimmed through the paper but didn't see any estimate for a date for the genetic diversion of the Australian Boababs.

Out of curiousity, why would that be considered offensive to Australian aboriginals?

It's generally the case that indigenous peoples have their own origin stories, which tend to not easily align with scientific explanations. Which is tricky because they have often experienced colonial exploitation and rejection of their cultures, and the science can come off as more of the same (even if it's true).

>It's generally the case that indigenous peoples have their own origin stories, which tend to not easily align with scientific explanations.

This, indigenous people everywhere always claim to be the first peoples and that they originated in whatever area they are indigenous to, even if it's obviously not true. It causes a lot of problems for science because they want to claim ownership of bones or artifacts from cultures that predate their own and prevent those items from being studied.

Fun fact: The Navajo speak of the Anasazi ("ancient enemies"/"ancient ones") as the tribe that used to occupy the land they later lived on, and explicitly consider them to be "those who are different from our people", not their own tribe.

That's awesome. Here a group of nomadic plains Indians shut down research into ancient mounds built by totally different prehistoric people. I get that some of these issues need to have some sensitivity around them, and research in the past wasn't always done with the appropriate level of reverence, but the pendulum has swung the other way now where we give too much credence towards avoiding hurt feelings that have no basis in reality.

Wouldn't you want informed consent if a scientist wanted to dig up your relatives' graves for research? It's just a scientific ethics question, combined with sovereignty issues. You want to do research on someone else's land in a different jurisdiction, it makes sense to know their laws and ask them for permission first.

Without safeguards like that you end up with HeLa and such.

Sure if it was my actual relatives, I'm not worried about people I'm definitely not descended from that lives several thousands of years ago though. The pendulum has swung too far in favor of people claiming ownership to graves that have no relationship to them.

The Kimberly rock drawings are some of the oldest in Australia, and an intrinsic part of Aboriginal culture in the region which they are found. Assigning their origin to a non-aboriginal source was considered disrespectful by some.

There was a massive one back in South Africa that must have been a thousand years old. Naturally someone put a pub in it. Must have been tree-cky.

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