High Above Sea Level, Evolutionary Hot Spots

9

In 1799 the great naturalist Alexander von Humboldt and his companions set out from Caracas, Venezuela, to climb the Andes. They struggled up a mountainside, enveloped in mist so thick they had to clamber over rocks by hand. When the fog cleared, von Humboldt was left astonished by the view. Vast grasslands stretched all around him, home to an astonishing number of different trees, shrubs, and flowers.

“Nowhere, perhaps, can be found collected together, in so small a space, productions so beautiful and so remarkable in regard to the geography of plants,” von Humboldt later wrote.

Von Humboldt had stumbled into a remarkable ecosystem, known as a Páramo. Páramos blanket the Andes in Venezuela, Ecuador and Colombia, growing at altitudes between 9,200 and 14,800 feet above sea level.

“They’re like islands in a sea of forest,” said Santiago Madriñán, an expert on Páramos at the University of the Andes in Colombia. All told, Páramos cover about 13,500 square miles — an area the size of Maryland. In that small space, Dr. Madriñán and other researchers have found 3,431 species of vascular plants, most of them found nowhere else on Earth. The Páramos are home to strange variations on familiar forms, such as a daisy known as Espeletia uribei that grows as tall as trees.

Written By: Carl Zimmer
continue to source article at nytimes.com

9 COMMENTS

    • In reply to #2 by Mr DArcy:

      And the slowest place for evolution is probably in the rocks some 5 miles down.An interesting article though. The real world is just so fascinating !

      No, there’s a much slower place apropos of evolution; between some people’s ears.

      S G

  1. High-altitude life is fascinating to me, including the adaptations of humans. I grew up in Leadville, Colorado, North America’s highest established town at 10,152 feet above sea level. My father was a mining engineer at a huge molybdenum mine in the mountains and spent his workdays at well over 12,000 feet. We spent our winters at nearby ski resorts (back when skiing was way more affordable than it is now) that had base elevations of 9,000 feet or more and went up from there. Driving in almost any direction out of town required crawling over mountain passes that exceeded 11,000 feet and in one memorable case, a terrifying gravel road in the Mosquito range that topped out at nearly 14,000 feet.
    Summers were short and plant life limited to aspens, lodgepole pines, alpine firs, and some of the farthest-south tundra found in the northern hemisphere. What is interesting is how quickly humans can adapt physiologically to such conditions, having lived at these altitudes for such short times from an evolutionary perspective. Bolivian and Peruvian tribes in the altiplano live at over 12,000 feet, as do Tibetans. These people have a body habitus that conserves heat and have fascinating abilities to control their body temperatures and perform hard physical exercise in a low-oxygen environment and at atmospheric pressures that would cause most humans to pass out. Many people who had lived in Leadville for only a few generations (since it was founded in the late 1800s as a silver and lead-mining town) had blood thick with red cells, almost to polycythemia levels, to enable them to function up where the air is rare. When we moved to a town in Montana that was only at 5,000 feet, we suffered for months from headaches, high blood pressure and other ailments doctors attributed to our “thick” blood. I knew many people who became sick when they left the “hill” – and many tourists who became deathly ill with pulmonary and cerebral edema when they came there to ski or just drive over the Rockies. It always fascinated me. To this day, even though I now live at sea level, I never get altitude sickness when I go up high. When I look at people (and animals and plants) living at high altitude, it’s fascinating how quickly selection works to bring about such dramatic adaptations over such a short time on an evolutionary scale.

    • Thanks for that sue, I have seen other examples of accelerated adaptation. Millions of years did not pass. Only a few generations. Evolution is amazing I think! Cat Stevens wrote a song about it, “Looking for a thick blooded woman.”In reply to #3 by Sue Blue:

      High-altitude life is fascinating to me, including the adaptations of humans. I grew up in Leadville, Colorado, North America’s highest established town at 10,152 feet above sea level. My father was a mining engineer at a huge molybdenum mine in the mountains and spent his workdays at well over 12…

  2. They struggled up a mountainside, enveloped in mist so thick they had to clamber over rocks by hand.

    There are many extremophyle niches in the high Andes. There is also huge potential for line species to develop right up the fijord west coast where strips of altitude specific habits run along valleys, round headlands and up the next valley for thousands of miles.

    At sea-level the Atacama desert is the driest place on Earth, with many high altitude habitats being similarly totally dependent on sea-fogs for moisture. Given the dry and frosty conditions at altitude, plus tropical sun, wind, and high UV radiation, there are extreme environmental pressures on all life. Evaporation is also high because the low air pressure lowers the boiling point of water.

    @OP- Páramo plants also evolved a wide range of defenses against the elements. Espeletia uribei, the daisy tree, grows white hairs on its flowers to protect them from damaging ultraviolet rays, while covering its stem with a thick layer of dead leaves to keep it warm.

    In these sorts of conditions plants develop defences such as thick coverings of hairs or spines, waxy coatings on photosythetic surfaces, retained dead leaves, bulbs, growth in tight clumps, or tap-roots which retract the short stems below soil level during droughts.

    Crown of Venezuelan Paramos: A New Species from the Daisy Family, Coespeletia Palustris http://www.sciencenewsline.com/articles/2013110719140026.html

    http://www.lonelyplanet.com/ecuador/wildlife/plants#280337
    Some 25, 000 species of vascular plants reside in Ecuador, and new species are being discovered every year. Compare this number to the 17, 000 species found on the North American continent! Plants in Ecuador are generally unique to their habitat, and the following are Ecuador’s primary habitats.

    Páramo

    Above the cloud forests lie the Andes’ high-altitude grasslands and scrublands, known as the páramo. The páramo is characterized by a harsh climate, high levels of ultraviolet light and wet, peaty soils. It is an extremely specialized habitat unique to the neotropics (tropical America) and is found only in the area starting from the highlands of Costa Rica to northern Peru.

    The páramo is dominated by cushion plants, hard grasses and small herbaceous plants that have adapted well to the harsh highland environment, and often look strange and interesting. Most plants up here are small and compact and grow close to the ground. An exception is the giant Espeletia, one of the páramo’s strangest sights.

  3. On we go. It just keeps getting more and more interesting.

    The ocean deeps await, and I await their secrets.

    I often wonder of what my grandfather, who died before I was born, would make of it all. Not just the discoveries themselves but the fact that we can sit in front of a screen in the comfort of our own homes and see and ear it all unfolding, in the depths and the heights and within ourselves.

  4. One of the features of the Americas, is the high altitude habitats which run from the Rockies, through Mexico, all the way to Patagonia. This provides some long linear climates/habitats, high in the equatorial regions, but which move to lower altitudes along the hillsides as they progress towards the poles. This can give rise to many “line species” where the “end species” at opposite ends of a connected line of inter breeding individuals are quite different in size, form, or genetics.

    http://en.wikipedia.org/wiki/Species-complex

    Such groups of species with a complex-type relationship between species may occur in a line – undergoing rapid speciation – or where such speciaton has recently occurred, meaning species separation mechanisms or traits which distinguish species have yet to develop in full. Such cases may leave some species paraphyletic at the species level and lead to hybrid species, making phylogeny/phylogenetic analysis difficult.

  5. Tectonic forces and Volcanic regions especially super volcanic ‘hot spots’ around Earth are likely to be the main generators of life and so may also function as evolutionary starting places…….Like the rift valley in Africa and Lake Toba in Indonesia etc

    Its amazing that Hot spots stay where they are deep in the Earth and the tectonic landmasses continually move over them, changing the position of the volcanos that will burst through the surface of land….piercing the continents as they pass

Leave a Reply