The strangest flower on Earth

Anyone know what the world's largest flower is?

Chances are, some of you know that honor goes to the bizarre Indonesian species Rafflesia arnoldi, which produces flowers that can get to be 120 centimeters across.  Not only are they huge, they are (1) really weird-looking, and (2) smell like rotting meat in order to attract the flies that pollinate them.

Rafflesia arnoldi  [Image licensed under the Creative Commons ma_suska, Rafflesia sumatra, CC BY 2.0]

The first time I saw a photograph of this plant, I was immediately reminded of the Lost in Space episode "Attack of the Monster Plants," which was a real favorite of mine when I was a kid, not only because who wouldn't love a show about monster plants, but because Judy Robinson was in peril during this episode and to say I was madly in love with Judy Robinson is rather an understatement.

Be that as it may, the reality of Rafflesia is almost as weird as Judy's spaceship-fuel-eating alien plants.  The flower is enormous but the rest of the plant is minuscule, only a thin ribbon of translucent tissue that punctures the roots of vines of the rainforest genus Tetrastigma, getting all its nutrients from the host plant rather than from photosynthesis.  The only time any part of the plant is above ground is when it's flowering.  After that, the flowers wither, the fruits containing thousands of nearly microscopic seeds that are thought to be dispersed when tree shrews eat the fruit and poop out the seeds somewhere else.  But the plant's rarity, and the fact that during most of its life cycle you could walk right by it (or more likely, over it) without knowing, not that much is known for sure.

Another thing that's surprising about the family (Rafflesiaceae) is that its nearest relatives are euphorbias -- which include a huge range of plants united by having tiny, insignificant flowers and milky toxic sap and looking absolutely nothing like Rafflesia.  A number of euphorbs look superficially like cacti, with reduced or absent leaves and sharp spines, but the milky sap and inconspicuous flowers would clue you in to the fact that the similarities are due to convergent evolution.  The most familiar euphorb is the poinsettia -- the bright red, pink, or cream-colored parts are not actually petals but modified leaves.  (The flowers themselves are the little b-b sized bits at the center.)

So what this shows is that to figure out evolutionary relationships, you can't rely on what things look like.  As odd as it is, the spiky candelabra spurge (Euphorbia ingens) is a cousin of the bizarre Rafflesia.

If all that isn't weird enough, consider a study that just came out a couple of weeks ago in Current Biology that looked at another member of Rafflesiaceae, the genus Sapria.  (They're very similar to Rafflesia, differing only in a few not-very-significant botanical details.)  This study did an extensive analysis of the genetics of Sapria, and found something bizarre; during its descent from its euphorbia-like ancestors, Sapria (and presumably the rest of the family Rafflesiaceae) has not only lost just about all of its physical structure, but half of its genome -- including the entire array of genes that produce chloroplasts.  Stranger still, in the process it has picked up genetic material from its host, something called horizontal transfer.

So this puts paid to the incorrect notion a lot of people have that evolution always makes things bigger, stronger, smarter, and more complex.  Evolution is the law of whatever works at the time, and if what works is to jettison half the DNA along with chloroplasts, leaves, and true roots, that can happen.  And if you think about it, it makes sense; if you're a plant that spends nearly its entire life underground, why waste resources making structures like leaves and chloroplasts, not to mention all the proteins and pigments that go into making them work?  The oddest thing about the genetics, though, is that a lot of the genes that Sapria has picked up from its hosts don't seem to do anything; they appear to be "non-coding regions" of DNA that don't have any obvious function.  "There's something weird and different going on in this species," said Tim Sackton of Harvard University, who co-authored the paper, in an interview with Science News.  "Maybe these organisms that stretch the boundaries of existence tell us something about how far the rules can be bent before they can be broken."

Rafflesia and its relatives are certainly some of the strangest members of the plant kingdom, so much so that you have to wonder what other peculiarities are going to be uncovered by further analysis.  I just hope we don't find out that it eats rocket fuel and creates evil duplicates of people, because Judy Robinson barely escaped with her life, and that is not okay.

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Science writer Elizabeth Kolbert established her reputation as a cutting-edge observer of the human global impact in her wonderful book The Sixth Extinction (which was a Skeptophilia Book of the Week a while back).  This week's book recommendation is her latest, which looks forward to where humanity might be going.

Under a White Sky: The Nature of the Future is an analysis of what Kolbert calls "our ten-thousand-year-long exercise in defying nature," something that immediately made me think of another book I've recommended -- the amazing The Control of Nature by John McPhee, the message of which was generally "when humans pit themselves against nature, nature always wins."  Kolbert takes a more nuanced view, and considers some of the efforts scientists are making to reverse the damage we've done, from conservation of severely endangered species to dealing with anthropogenic climate change.

It's a book that's always engaging and occasionally alarming, but overall, deeply optimistic about humanity's potential for making good choices.  Whether we turn that potential into reality is largely a function of educating ourselves regarding the precarious position into which we've placed ourselves -- and Kolbert's latest book is an excellent place to start.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

A botanical messiah

Given all the horrible and discouraging news we're bombarded with on a daily basis, sometimes it's nice to focus on some of the positive things humans are doing.

Today we'll look at Carlos Magdalena, the Spanish-born botanical horticulturist who works with saving severely endangered plant species in his lab at Kew Gardens, near London.  As a brief aside, Kew is one of those places I think everyone should visit at some point in their lives.  Besides simply being gorgeous, it has one of the most extensive collections of rare plants in the world, and a half-day's walk through their greenhouses (or "glasshouses" as they call them in the UK) will open your eyes to the astonishing diversity gifted to us by the process of evolution.

The darker side of this, however, is the extent to which the world's plant species are threatened.  It's a general rule in evolutionary biology that when conditions are stable, natural selection favors specialization (witness the hundreds of species of hummingbirds in the Andes, many of which specialize in living at a narrow range of altitudes and feeding on only one or two species of flowers).  Changing conditions, however, favor generalists -- such as the preponderance of rats and pigeons in most of the world's cities.

The problem is that human actions have caused formerly stable ecosystems to start changing quickly, and the specialists are being hit hard.  Nowhere is this more obvious than the Amazonian rain forest, where a policy of turning over tracts of woodland on what honestly is marginal soil to agricultural and mining interests, something that has only accelerated with the reckless and ignorant policies of Brazilian president Jair Bolsonaro.  (Encouraged, it must be added, by Donald Trump, whose attitude toward the environment seems to be "use it up and who gives a shit what happens afterward.")

The result has been devastating.  Magdalena estimates that one in five plant species worldwide is on the way to extinction, and that species go extinct every day -- some without ever being catalogued and studied.

But I said this was going to be an upbeat post, so I want to look at what Magdalena is doing to fight against this -- and how his efforts may be saving dozens of species from disappearing forever.

Magdalena's specialty is figuring out how to germinate seeds.  It's trickier than it sounds; if you're a gardener you probably buy packets of seeds at your local home and garden store, but what you may not realize is that the reason those varieties are sold is because they've got the unusual feature of being easy to germinate.  Where I live, here in upstate New York, seeds of most native species need to be stratified in order to germinate -- they need to be exposed to a period of cold, simulating passage through the winter.

Explaining why my attempts as a kid to grow an apple tree from a seed in an apple I'd eaten all resulted in failure.

Other plants, though, have additional complications.  Despite my background in evolutionary biology, one thing I've never quite understood is why some plants have seeds that are ridiculously difficult to germinate (many types of orchids come to mind).  The only reason I've come up with goes back to specialization; if a plant lives in a very stable ecosystem with an extremely narrow range of conditions, evolving to require those conditions and no others isn't a significant disadvantage.  It only becomes a problem if you take the seeds and try to sprout them elsewhere -- because then you have to somehow emulate all of those factors in your greenhouse.

But Magdalena might be the world's expert on solving this problem.  He single-handedly saved the world's smallest water lily, Nymphaea thermarum, when the only known population of the plant (in Rwanda) was destroyed in 2008.  His work with this and other species of severely endangered plants led to his being dubbed in a Spanish newspaper as el mesias de las plantas -- "the messiah of plants."

It's an apt moniker.

Nymphaea thermarum [Image courtesy of Carlos Magdalena and the Royal Botanical Gardens at Kew]

What Magdalena is trying to accomplish, however, sometimes must seem an uphill battle.  "There are seventy species of plants that we know of that have less than ten individuals left," he said in the interview linked above.  "In some cases, there is just the last individual plant left, or there are the last three individuals left.  Those will probably be more of a priority because the clock is ticking, and these specimens might have only few minutes left.  These last individuals could disappear by the end of this week.  Maybe the individuals could disappear with the next cyclone, or when the next pest gets introduced."

He's currently working on plant species from the island of Mauritius, best known to biologists as the former home of the dodo.  He was successful at germinating the seeds of a species in the genus Elaeocarpus for which only two individuals were left alive, but has been unsuccessful thus far at propagating the palm Hyophorbe amaricaulus -- which is down to a population of one.

However difficult his job can be, Magdalena is impelled to keep at it because of its critical importance.  "We cannot stabilize the planet’s climate if there is no tropical forest," he said.  "We cannot ensure that we will have resources to support humankind in terms of medicines, food, water and more without protecting these forests...  Plants are going extinct every single day, probably every single hour.  It’s like killing all your golden-egg hens systematically.  It is so nonsensical.

"We really need to realize that protecting the forests is not optional," he added.  "This is not something that’s just idealistic.  This is at the very core of our survival."

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Long-time readers of Skeptophilia have probably read enough of my rants about creationism and the other flavors of evolution-denial that they're sick unto death of the subject, but if you're up for one more excursion into this, I have a book that is a must-read.

British evolutionary biologist Richard Dawkins has made a name for himself both as an outspoken atheist and as a champion for the evolutionary model, and it is in this latter capacity that he wrote the brilliant The Greatest Show on Earth.  Here, he presents the evidence for evolution in lucid prose easily accessible to the layperson, and one by one demolishes the "arguments" (if you can dignify them by that name) that you find in places like the infamous Answers in Genesis.

If you're someone who wants more ammunition for your own defense of the topic, or you want to find out why the scientists believe all that stuff about natural selection, or you're a creationist yourself and (to your credit) want to find out what the other side is saying, this book is about the best introduction to the logic of the evolutionary model I've ever read.  My focus in biology was evolution and population genetics, so you'd think all this stuff would be old hat to me, but I found something new to savor on virtually every page.  I cannot recommend this book highly enough!

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

The tipping point

There's a common comment from climate change deniers that I'm sick unto death of, and it usually takes the form of something like "the Earth's climate has had ups and downs in the past, and life has gone along just fine."

First, it's the pure ignorance of this attitude that gets me.  If you did ten minutes' worth of research online, you'd find that a number of these "ups and downs" coincided with mass extinctions.  Life survived, yes, but dramatic losses in biodiversity and overall population numbers hardly constitutes "getting along just fine."  (In fact, the largest mass extinction ever -- the Permian-Triassic Extinction, which wiped out an estimated 96% of marine species and 65% of terrestrial species -- was coincident with a huge spike in temperature and atmospheric carbon dioxide, thought to have been triggered by a colossal volcanic eruption.)

But second, and honestly worse, is the blithe attitude that we can continue doing whatever we want to the environment and face no consequences whatsoever.  This raises entitlement to the level of an art form; apparently, we humans occupy such an exalted niche that no matter what we do, the rest of nature is magically going to make sure we not only survive, but thrive.

Even the most diehard deniers, however, are getting some serious hints that their determination to ignore science is not working out so well.  First of all, we have the fires in the Amazon, which have reached unprecedented levels in Brazil, with 74,000 acres burned to the ground already.  The cause is twofold -- the natural dry season, and the incomprehensible policy by Brazilian president Jair Bolsonaro of recommending large-scale slash-and-burn to "encourage agriculture."  The problem is larger in scale than just South America, however.  Environmental scientist Jonathan Foley explained why in an interview with Science News:

Some computer models... show a hypothetical scenario that when we clear rainforest, it starts to almost immediately warm up and dry out the atmosphere nearby.  When we stand in a forest, it feels cool and moist.  But when you clear-cut large areas of the forest, the air right around you gets hotter and drier, and it affects even rainfall patterns.  The worry is if you start clear-cutting more of the Amazon, in theory, a tipping point could be reached where the rest of the forest dries out, too. 

If that happens, the idea is that the Amazon could flip suddenly from being a rainforest to being a dry savanna-like ecosystem.  We’re not absolutely certain about it, but even that theoretical possibility is kind of terrifying...  Globally, about 10 to 15 percent of our CO2 emissions comes from deforestation.  If this is going back up again in Brazil, that’s going to make climate change even worse.

The only amendment that needs to be made to Foley's statement is his use of the word "if" in the last sentence.

Smoke from the 2019 Amazonian wildfires [Image is in the Public Domain, courtesy of NASA]

The other piece of alarming information this week comes from some research done at Stockholm University that firmed up a link between the salinity of the North Atlantic and climate throughout the world.  The team, made up of David K. Hutchinson, Helen K. Coxall, Matt OʹRegan, Johan Nilsson, Rodrigo Caballero, and Agatha M. de Boer, were studying the Eocene-Oligocene Transition (EOT), which occurred 34 million years ago and involved a shift from a "hothouse" to "icehouse" climate.  

The authors write:

The Eocene–Oligocene transition (EOT), ~34 Ma ago, marked a major shift in global climate towards colder and drier conditions and the formation of the first Antarctic ice sheets.  A gradual decrease in CO2 is thought to be the primary driver of the transition, causing long-term cooling and increasing seasonality through the Eocene, culminating in the glaciation of Antarctica.  Deep water circulation proxies suggest that the EOT, including the preceding 1 Myr, also marked either the onset or strengthening of an Atlantic meridional overturning circulation (AMOC).

Catch that?  An event occurring the North Atlantic is the probable trigger for the formation of the Antarctic Ice Sheet, and a radical change in Earth's climate -- and, unsurprisingly, a massive extinction that wiped out 20% of the Earth's species (large mammals were the hardest hit).

What Hutchinson and his team showed is that the likely cause of this transition was the closing of a oceanic channel between the Arctic Ocean and the North Atlantic.  The Arctic Ocean at that time had very low salinity (something the team demonstrated using the species of algae that show up in the fossil record from that time and place).  As long as the channel was open, fresh water flooded into the North Atlantic, keeping the salinity of the surface water low.  When the channel closed due to tectonic movement, the salinity of the surface of the North Atlantic spiked.  Saline water is more dense than fresh water, so this surface water began to sink, kicking off the "North Atlantic Thermohaline Circulation" and (more germane to our discussion here) drawing down dissolved carbon dioxide by the metric ton.

The result: a drastic drop in temperature, Antarctica becoming an ice-covered wasteland, and a mass extinction worldwide.

How anyone can read this and not be freaking out over the spike in carbon dioxide we've seen in the last hundred years -- that appears to be the fastest carbon dioxide concentration change anywhere in the geological record -- is beyond me.  There's no doubt that there's a tipping point, as the Eocene-Oligocene Transition shows.  The only question is where that tipping point is -- and whether we've already passed it.

What's driving it all is money.  Altering our lifestyle, protecting the rain forests, and divesting ourselves from fossil fuels all require that we make sacrifices ourselves, but more importantly, that we end the chokehold the fossil fuels industry has on our elected officials.  Of course the politicians don't want anyone to understand and accept climate science, because that would mean cutting off one of their biggest sources of donations -- the petrochemical industry.

It is fitting to end with a quote from Upton Sinclair: "It is difficult to get a man to understand something, when his salary depends upon his not understanding it."  The problem is, here what we're jeopardizing is not simply someone's salary, but the long-term habitability of the Earth.

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This week's Skeptophilia book recommendation is about a subject near and dear to my heart; the possibility of intelligent extraterrestrial life.  In The Three-Body Problem, Chinese science fiction writer Cixin Liu takes an interesting angle on this question; if intelligent life were discovered in the universe -- maybe if it even gave us a visit -- how would humans react?

Liu examines the impact of finding we're not alone in the cosmos from political, social, and religious perspectives, and doesn't engage in any pollyanna-ish assumptions that we'll all be hunky-dory and ascend to the next plane of existence.  What he does think might happen, though, makes for fascinating reading, and leaves you pondering our place in the universe for days after you turn over the last page.

[Note: if you purchase this book from the image/link below, part of the proceeds goes to support Skeptophilia!]