kottke.org posts about biology
Microorganisms are so small compared to humans that you might be tempted to think that they’re all about the same size. As this video shows, that is not at all the case. The rinovirus and polio virus are 0.03 micrometers (μm) wide, a red blood cell is 8 μm, a neuron 100 μm, and a frog’s egg 1 mm. That’s a span of 5 orders of magnitude, about the same difference as the height of a human to the thickness of the Earth’s atmosphere.
Watching the animation, you might have noticed the T4 bacteriophage, which looks like a cross between the aliens in Arrival and a lunar lander. Can’t be real, right? Bacteriophages are really real and terrifying…if you happen to be a bacteria. Bacteriophages attack by attaching themselves to bacteria, piercing their outer membranes, and then pumping them full of bacteriophage DNA. The phage replicates inside of the bacteria until the bacteria bursts and little baby bacteriophages are exploded out all over the place, ready to attack their own bacteria.
This is a fascinating thread by Milena Popova about the differing performances of male and female athletes at the Winter Olympics. As they point out, humans are sexually dimorphic but the story doesn’t end there. Bodies are also socially constructed.
Physiology is a thing, but physiology is shaped and mediated by our social context.
Look back at those pictures of “women”. Those petite, delicate bodies, those faces we process as “beautiful”. Those are the qualities that globally dominant Western cultures associate with “femininity”.
And sport is one of the institutions that fiercely guards and reproduces dominant ideas about gender, masculinity and femininity. This plays out differently in different sports.
Generally, men and women compete separately. And for the purposes of sport “men” and “women” are defined as people whose bodies were assigned male or female at birth and whose gender matches that assignment.
The obvious example here is South African runner Caster Semenya. But Popova continues with a more subtle (and admittedly speculative) situation:
Now, what really gets me is snowboarding. Because on the face of it that’s not a sport that’s judged on the same gendered criteria of artistry and aesthetics as figure skating or gymnastics.
You’d think under all the skiing gear, helmets, scarves and goggles, it would be quite hard to perform femininity.
And still, as my friend whom I made watch slope style and half pipe for the first time in her life last night pointed out, the body types of the men and women riders are really rather different. You can tell even under all the gear.
And that translates to performance. Women get an amplitude of about 3m above the half pipe, men about 4-5m. The best women do 1080s (three revolutions), the best men 1440s (four revolutions).
…
But much like any other subculture snowboarding reproduces hierarchical structures. Moves are named after people, some people find it easier to access than others (hint: it’s a massively expensive sport), some people set trends.
One of the structures it reproduces is a gendered hierarchy. It’s a very masculine culture. Women find it harder to access the sport, find it harder to be taken seriously as athletes in their own right rather than “just hangers-on”.
And I have the sneaky suspicion that because the people with the most subcultural capital tend to be men and they decide whom they will admit and accept to the community, there are certain looks and body types of women who find it less hard (not easy!) to gain access.
And those happen to be the body types that may find it harder to do 1440s and to get 5m amplitude above the half pipe.
Another example from figure skating is Surya Bonaly, a French figure skater who landed a backflip on one skate in a performance at the 1998 Olympics. While backflips weren’t banned because of Bonaly’s relative ease in performing them (as claimed here), her athletic style was outside the norm in women’s figure skating, in which traditional femininity is baked right into the rules & judging. This was also a factor in Tonya Harding’s career (as depicted in I, Tonya).
Anyway, super interesting to think about.
Nature has amassed 3.8 billion years of R&D on how to engineer and design things and systems. So when designers are looking at how to solve problems, they should pay closer attention to how the evolutionary process dealt with similar situations. For example, an engineer working on a redesign of the Japanese bullet train used his birdwatching knowledge to borrow design elements from birds like a kingfisher, an owl, and a penguin.
Japan’s Shinkansen doesn’t look like your typical train. With its long and pointed nose, it can reach top speeds up to 150-200 miles per hour.
It didn’t always look like this. Earlier models were rounder and louder, often suffering from the phenomenon of “tunnel boom,” where deafening compressed air would rush out of a tunnel after a train rushed in. But a moment of inspiration from engineer and birdwatcher Eiji Nakatsu led the system to be redesigned based on the aerodynamics of three species of birds.
I love the idea of the Shinkansen as a chimerical creature constructed from the bodies of three very different types of birds. (via the kid should see this)
In her book The Sixth Extinction, Elizabeth Kolbert warns that we are in the midst of the Earth’s sixth mass extinction of life, this time caused by humans.
Over the last half a billion years, there have been five mass extinctions, when the diversity of life on earth suddenly and dramatically contracted. Scientists around the world are currently monitoring the sixth extinction, predicted to be the most devastating extinction event since the asteroid impact that wiped out the dinosaurs. This time around, the cataclysm is us.
This is a mainstream view of humanity’s effect on the Earth flora and fauna…for evidence, you don’t need to look any further than all of the large mammal species that have gone extinct or are endangered because of human activity.
A more controversial take is offered by Chris Thomas in his recent book, Inheritors of the Earth: How Nature Is Thriving in an Age of Extinction. Thomas allows that there’s a “mini mass extinction” happening, but he also argues that the extreme evolutionary pressure brought by our increasing dominance of our planet’s ecosystems will result in a “sixth mass genesis”, a dramatic increase in the Earth’s biodiversity.
Human cities and mass agriculture have created new places for enterprising animals and plants to live, and our activities have stimulated evolutionary change in virtually every population of living species. Most remarkably, Thomas shows, humans may well have raised the rate at which new species are formed to the highest level in the history of our planet.
Drawing on the success stories of diverse species, from the ochre-colored comma butterfly to the New Zealand pukeko, Thomas overturns the accepted story of declining biodiversity on Earth. In so doing, he questions why we resist new forms of life, and why we see ourselves as unnatural. Ultimately, he suggests that if life on Earth can recover from the asteroid that killed off the dinosaurs, it can survive the onslaughts of the technological age.
Vox’s Ferris Jabr recently interviewed Thomas about his views. When asked about the “sixth mass genesis”, Thomas answered:
The history of life on Earth is a history of extinctions and ecological failures, but it is also a story of formation of new forms and spread of those new forms around the world. The net result has been a gain in diversity. In the human era we are seeing great losses, but we are also seeing all these biological gains of new animals and plants spreading around the world, new hybrids coming into existence. I am not saying there is yet a balance between the two. I accept the losses, but it is also scientifically, and in terms of our human attitudes to nature, extremely interesting to contemplate the gains simultaneously.
If the processes that are going on at the moment continue for a very long time, it is my expectation that the number of species on Earth will grow enormously. We are moving species of existing animals and plants back and forth across the world, so that they are all arriving in new geographic regions. We know when species have done this in the ancient past, they have turned into new species in those different regions. If you fast-forward a million years or a few million years, all of these introduced species that leave surviving descendants will have turned into new species. And that is going to generate many more species. We have effectively created a massive species generator.
That certainly does put an interesting spin on extinction and invasive species.
In the first in a series of videos, Kurzgesagt tackles one of my favorite scientific subjects: how the sizes of animals governs their behaviors, appearance, and abilities. For instance, because the volume (and therefore mass) of an organism increases according to the cube of the increase in length (e.g. if you double the length/height of a dog, its mass roughly increases by 8 times), when you drop differently sized animals from high up, the outcomes are vastly different (a mouse lands safely, an elephant splatters everywhere).
The bit in the video about how insects can breathe underwater because of the interplay between the surface tension of water and their water-repellant outer layers is fascinating. The effect of scale also comes into play when considering the longevity of NBA big men, how fast animals move, how much animals’ hearts beat, the question of fighting 100 duck-sized horses or 1 horse-sized duck, and shrinking people down to conserve resources.
When humans get smaller, the world and its resources get bigger. We’d live in smaller houses, drive smaller cars that use less gas, eat less food, etc. It wouldn’t even take much to realize gains from a Honey, I Shrunk Humanity scheme: because of scaling laws, a height/weight proportional human maxing out at 3 feet tall would not use half the resources of a 6-foot human but would use somewhere between 1/4 and 1/8 of the resources, depending on whether the resource varied with volume or surface area. Six-inch-tall humans would potentially use 1728 times fewer resources.
See also The Biology of B-Movie Monsters, which is perhaps the most-linked article in the history of kottke.org.
At the height of his power and wealth in the 1980s, Colombian drug lord Pablo Escobar was one of the richest men in the world. On one of his many properties, Escobar built a private zoo, complete with animals from around the world, including zebras, rhinos, ostriches, and hippos.
As Escobar’s power waned and he was eventually killed, the animals in his zoo were transferred to proper zoos…except for four hippos that escaped into the wilderness. Nature did its thing and now the Colombian wild hippo population stands at nearly 40 and could rise to 100 in the next decade.
For the second part of an ongoing series, Wired asked biologist Neville Sanjana to explain CRISPR to five people with different levels of knowledge: a 7-year-old, a high school student, a college student, a grad student, and an expert on CRISPR. As I began to watch, I thought he’d gone off the rails right away with the little kid, but as soon as they connected on a personal issue (allergies), you can see the bridge of understanding being constructed.
The first installment in the series featured a neuroscientist explaining connectomes to five people.
The Biodiversity Heritage Library maintains a huge trove of plant and animal drawings that they’ve put up on Flickr for free.
The Biodiversity Heritage Library (BHL) is a consortium of natural history and botanical libraries that cooperate to digitize the legacy literature of biodiversity held in their collections and to make that literature available for open access and responsible use as a part of a global “biodiversity commons.”
Over 110,000 images are available, organized into hundreds of albums. You could easily lose an entire afternoon in there.
P.S. While the Biodiversity Heritage Library doesn’t appear to be an official participant, Flickr’s The Commons project remains one of the under-appreciated gems of the Web.
Since life first formed on Earth billions of years ago, the ability of organisms to use more powerful and efficient energy sources has been key in driving the diversity and complexity of life. According to this provocative piece in Nature by Olivia Judson, the history of life on Earth can be divided into five energetic epochs characterized by the following energy sources: geochemical energy, sunlight, oxygen, flesh and fire.
The first two were present at the start, but oxygen, flesh and fire are all consequences of evolutionary events. Since no category of energy source has disappeared, this has, over time, resulted in an expanding realm of the sources of energy available to living organisms and a concomitant increase in the diversity and complexity of ecosystems. These energy expansions have also mediated the transformation of key aspects of the planetary environment, which have in turn mediated the future course of evolutionary change. Using energy as a lens thus illuminates patterns in the entwined histories of life and Earth, and may also provide a framework for considering the potential trajectories of life-planet systems elsewhere.
Organisms formed on Earth and changed the planet, which led to the formation of new organisms more suited to the new environment. For instance, when a type of bacteria evolved to turn sunshine into oxygen, it completely changed the planet.
In the absence of a biotic source of oxygen, trace quantities of the gas can be generated abiotically: water molecules can be split by sunlight or radioactive decay. However, these abiotic processes are much less efficient than their biotic equivalent. Had cyanobacteria, or something like them, never evolved, oxygen would never have built up in the atmosphere of the Earth.
But build up it did. Between 2.45 and 2.32 Ga, significant quantities of oxygen began to accumulate in the air, an episode known as the Great Oxidation Event. Before the Great Oxidation, atmospheric oxygen levels were less than 10^-5 of the present atmospheric level of ~21%. By ~2 Ga, they had risen to perhaps 0.1-1% of the present atmospheric level. Although the subsequent history of oxygen is complex and many details are uncertain, Earth’s atmosphere has contained an appreciable level of the gas ever since. (Full oxygenation of the oceans, however, would not happen until around 1.8 billion years after the Great Oxidation.)
The original piece in Nature is fairly readable for a science journal, but this summary in The Atlantic is worth a look if you’re short on time or attention. (via @CharlesCMann)
This is a stunning time lapse video of the cells in a tadpole egg dividing over a period of 33 hours. The filmmaker, Francis Chee, built a custom microscope and lighting system to capture the action.
I can say that it was done with a custom designed microscope based on the “infinity optical design” It is not available by any manufacturer. I built it. I used LEDs and relevant optics to light the egg. They too were custom designed by me. The whole microscope sits on anti-vibration table. I have to say that it doesn’t matter too much what microscope people use to perform this. There are countless other variables involved in performing this tricky shot, such as for example: the ambient temperature during shooting; the time at which the eggs were collected; the handling skills of the operator; the type of water used; lenses; quality of camera etc etc.
Chee says in the comments that he’s perfecting his technique and hopes to capture a complete egg-to-tadpole video in the near future. His other videos are worth a look too, like this mushroom time lapse and this gruesome video of a praying mantis eating a fly alive. (via colossal)
Rove beetles have evolved the ability to look and smell enough like army ants that they can live amongst them. Until it’s dinner time.
The impostors look and smell like army ants, march with the ants, and even groom the ants. But far from being altruistic nest-mates, these creatures are parasitic beetles, engaged in a game of deception. Through dramatic changes in body shape, behavior, and pheromone chemistry, the beetles gain their hostile hosts’ acceptance, duping the ants so they can feast on the colony brood.
As you can see in the photo above, the resemblance is strong…the beetle is in the foreground with the larger headed ant behind.
But that’s not even the most amazing part. A recent discovery has shown that rove beetles have evolved this capability at least a dozen separate times, suggesting that certain evolutionary possibilities are more likely than other in the presence of strong environmental factors and traits.
The ant-mimicking beetles all belong to the Staphylinidae, or rove beetles, but don’t mistake them for close relatives: the last common ancestor of the beetles in the study lived 105 million years ago, at about the time that humans split from mice. “What’s exceptional is that this convergent system is evolutionarily ancient,” says Parker. Although most other convergent systems, such as Darwin’s finches, three-spined stickleback, and African lake cichlid fish, are a few million years old at most, this newly discovered example extends back into the Early Cretaceous.
Given this great age, Parker and his co-author Munetoshi Maruyama of the Kyushu University Museum argue that their finding challenges Stephen J. Gould’s hypothesis that if time could be rewound and evolution allowed to replay again, very different forms of life would emerge. “The tape of life has been extremely predictable whenever rove beetles and army ants have come together,” says Parker. “It begs the question: why has evolution followed this path so many times?”
(via @stewartbrand)
Over a period of thirteen years beginning in the 1820s, John James Audubon painted 435 different species of American birds.1 When he was finished, the illustrations were compiled into The Birds of America, one of the most celebrated books in American naturalism. Curiously however, five of the birds Audubon painted have never been identified: Townsend’s Finch, Cuvier’s Kinglet, Carbonated Swamp Warbler, Small-headed Flycatcher and Blue Mountain Warbler.
These birds have never been positively identified, and no identical specimens have been confirmed since Audubon painted them. Ornithologists have suggested that they might be color mutations, surviving members of species that soon became extinct, or interspecies hybrids that occurred only once.
The specimen that Audubon used to paint Townsend’s Bunting is now in the Smithsonian Museum of Natural History, identified as Townsend’s Dickcissel, but no bird exactly like it has been reported, Dr. Olson, an authority on Audubon’s work, noted in an email. Ornithologists suggest that it is either a mutation of the Dickcissel or a hybrid of Dickcissel and Blue Grosbeak, she said.
And that’s not counting the ones he got wrong for other reasons:
And indeed, there are several birds painted and explained in Birds of America that are not, in fact, actual species. Some are immature birds mistaken for adults of a new species (the mighty “Washington’s Eagle” was, in all likelihood, an immature Bald Eagle). Some were female birds that didn’t look anything like their male partners (“Selby’s Flycatcher” was a female Hooded Warbler).
Audubon also painted six species of bird that have since become extinct: Carolina parakeet, passenger pigeon, Labrador duck, great auk, Eskimo curlew, and pinnated grouse. Here’s his portrait of the passenger pigeon:
There were an estimated 3 billion passenger pigeons in the world in the early 1800s — about one in every three birds in North America was a passenger pigeon at the time. Their flocks were so large, it took hours and even days for them to pass. Audubon himself observed in 1813:
I dismounted, seated myself on an eminence, and began to mark with my pencil, making a dot for every flock that passed. In a short time finding the task which I had undertaken impracticable, as the birds poured in in countless multitudes, I rose and, counting the dots then put down, found that 163 had been made in twenty-one minutes. I traveled on, and still met more the farther I proceeded. The air was literally filled with Pigeons; the light of noon-day was obscured as by an eclipse; the dung fell in spots, not unlike melting flakes of snow, and the continued buzz of wings had a tendency to lull my senses to repose… I cannot describe to you the extreme beauty of their aerial evolutions, when a hawk chanced to press upon the rear of the flock. At once, like a torrent, and with a noise like thunder, they rushed into a compact mass, pressing upon each other towards the center. In these almost solid masses, they darted forward in undulating and angular lines, descended and swept close over the earth with inconceivable velocity, mounted perpendicularly so as to resemble a vast column, and, when high, were seen wheeling and twisting within their continued lines, which then resembled the coils of a gigantic serpent… Before sunset I reached Louisville, distant from Hardensburgh fifty-five miles. The Pigeons were still passing in undiminished numbers and continued to do so for three days in succession.
100 years later, they were all dead. Which may have had at least one interesting consequence:
But the sad echo of the loss of passenger pigeons still reverberates today because its extinction probably exacerbated the proliferation of Lyme disease. When the passenger pigeons existed in large numbers, they subsisted primarily on acorns. However, since there are no pigeons to eat acorns, the populations of Eastern deer mice — the main reservoir of Lyme disease — exploded far beyond historic levels as they exploited this unexpected food bonanza.
For his new book, Evolution: A Visual Record, photographer Robert Clark has collected dozens of images that show the varying ways in which plants and animals have adapted to their changing surroundings.
Evidence of evolution is everywhere. Through 200 revelatory images, award-winning photographer Robert Clark makes one of the most important foundations of science clear and exciting to everyone. Evolution: A Visual Record transports readers from the near-mystical (human ancestors) to the historic (the famous ‘finches’ Darwin collected on the Galapagos Islands that spurred his theory); the recently understood (the link between dinosaurs and modern birds) to the simply astonishing.
The photo above is of a southern cassowary, a flightless bird that is particularly dinosaur-esque in stature and appearance.
French visual effects artist Maxime Causeret took a track from Max Cooper’s album Emergence and created these wonderful biologically inspired patterns and interactions.
Maxime also shows us a section of animated reaction-diffusion patterns, where simple chemical feedback mechanisms can yield complex flowing bands of colour — these forms of system were originally thought up by Alan Turing, and were part of the early seeds of the field of systems biology, which seeks to simulate life with computers, in order to better understand the systems producing the complexity we see in the living world. They were also the starting point of my main research area many years ago before I got lost in music! (where I began with the question of what patterns could be produced via reaction-diffusion forms of system as opposed to gene-regulatory network controlled patterning).
There’s a blue brain coral pattern at the 1:30 mark and a neuron-ish pattern at 2:30 that I wish would go on forever. Headphones recommended, psychoactive drugs optional. (via colossal)
Poachers in Africa in search of the biggest ivory tusks have altered the gene pool of African elephants in the process.
In Gorongosa National Park in Mozambique, 90 per cent of elephants were slaughtered between 1977 and 1992, during the country’s civil war. Dr Poole said that because poachers disproportionately targeted tusked animals, almost half the females over 35 years of age have no tusks, and although poaching is now under control and the population is recovering well, they are passing the tuskless gene down to their daughters: 30 per cent of female elephants born since the end of the war also do not have tusks.
“Females who are tuskless are more likely to produce tuskless offspring,” she said.
(via mr)
Update: Vox has an interesting look at the growing trend of tuskless elephants.
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