Accelerating Evolution, Part 3: Burgeoning Biosphere
Part 2was: How New Species Come toBe
Another related factor is the fuller use of ecological niches that are now only sparsely occupied. Nitrogen, an essential nutrient the shortage of which often is abottleneck in soil fertility, is already “fixed” or extracted from the atmosphere, achallenging biochemical procedure, by plants in the legume family. This very successful family includes not only edible beans but many other plants, including massive trees, and enables an increase in occupancy of low nitrogen habitats.
Where drought is the limiting factor, future plants may figure out how to extract water molecules from the air, or form communal root conduits extending long distances to far away water sources. In the ocean, long, descending root threads could help floating seaweeds extract more of the iron, phosphorous, and other nutrients they need from alarger volume of water when nutrient scarcity is abottleneck to surface water fertility.
Cold environments could be more densely populated when organisms there evolve sap and blood that contain better anti-freeze chemicals. Watermelon snow (colored red or pink by snow algae) is well known, and ice worms that live by eating such algae can burrow through ice, but disintegrate by essentially liquefying at just afew degrees above freezing. But the potential is much greater. The frozen wastelands of Antarctica and elsewhere could become covered with vegetation, probably not as tall as arain forest only because of insufficient nutrients in the icy substrate.
Rock surfaces often have lichens growing on them, but those rocks could become densely covered with avibrant, fast-growing mat of multiple competing lichen species which efficiently erode the rocky surface as they extract the minerals they need directly from the solidrock.
Even the sky can be ahabitat for life. Birds are nice but the potential goes way beyond our feathered friends. Moisture in clouds, nutrient-containing dust suspended in the atmosphere, and sunlight provide the basis for sustaining little photosynthetic algae cells, whose spores could continue to float high above even when the clouds that produced them dry out. These spores could contain essential minerals that agrowing algae cell needs, recycled from the parent cell that dried out earlier. Athriving ecosystem in the skies could develop. In fact, biomass living in clouds this day has the “potential to increase by as much as 20% per day” and is estimated to metabolize in the neighborhood of “1 million tons of organic carbon per year.” The bacteria Erwinia caratovora is just one species that spends part of its life cycle in the clouds. It has been discovered that some bacterial protein coats are built to encourage ice crystals in the sky to form around them. Some strains of Pseudomonas syringae, for example, are coated with proteins containing a “magic” 8amino acid sequence AGYGSTET which, unlike typical proteins, catalyzes ice crystal formation by aligning water molecules in an ice-like configuration. Such bacteria are called ice nucleators (INs) and are thought to seed clouds to encourage precipitation. This washes down seed bacteria far from where they started, helping them disperse across the Earth’s surface. The significance of this to weather and climate is unknown but potentially great, as clouds typically hold ten thousand microbes per cubic meter. In fact asurprising one third of ice crystals in clouds were found to be nucleated biologically in atest of skies over Wyoming. Sky-dwelling algae could be useful to humans of the distant future, who might transport them to the high clouds of Venus to play acritical role in terraforming an entire planet. Closer to home, we now know that asky teeming with different species of life is not as unprecedented aconcept as one might have guessed.
Tune in next time for Part 4: Doing it in Decades Instead of Hundreds of Millions ofYears
“Darwin himself observed, ‘offspring of each species will try…to seize…diverse places in the economy of Nature.… Each new variety or species, when formed, will generally take the place of…its less well-fitted parent.’” S. J. Gould,The Structure of Evolutionary Theory.
“Darwin said the natural end point of this process: ‘The same spot will support more life if occupied by very diverse forms.’” P. H. Barrett, P. J. Gautey, S. Herbert, D. Kohn, and S. Smith, eds., Charles Darwin’s Notebooks, 1836 – 1844, Cambridge University Press, 1987. Numerous other citations may be found by querying aweb search engine with Darwin’s quote.
“Thus this language varies somewhat among species.”: D. Berleant, M. White, E. Pierce, E. Tudoreanu, A. Boeszoermenyi, Y. Shtridelman and J. C. Macosko, The genetic code – more than just atable, Cell Biochemistry and Biophysics, 2009, vol. 55, no. 2, pp. 107 –116.
“…biomass living in clouds this day has the ‘potential to increase by as much as 20% per day’”: B. Christner, Cloudy with achance of microbes, Microbe Magazine, Feb. 2012, vol. 7, no. 2, pp. 70 – 75, http://www.microbemagazine.org/index.php/issue-archive/2.….s/february.
“…biomass living in clouds today…is estimated to metabolize in the neighborhood of ‘1 million tons of organic carbon per year’.” P. Amato, Clouds provide atmospheric oases for microbes, Microbe Magazine, Mar. 2012, vol. 7, no. 3, pp. 119 – 123, http://www.microbemagazine.org/index.php/issue-archive/2012-issues/march.
“The bacteria Erwinia caratovora is just one species that spends part of its life cycle in the clouds.” E. Newman, University of Wyoming scientist looks for bacteria in clouds, trib.com, May 4, 2012, http://trib.com/news/state-and-regional/university&#.….b0be7.html.
“Some strains of Pseudomonas syringae, for example, are coated with proteins containing the 8amino acid sequence AGYGSTET, which catalyzes ice crystal formation.” B. Christner, 2012.
“The significance of this to weather and climate is unknown but potentially great…”: C. Dell’Amore, 2009.
“…clouds typically hold ten thousand microbes per cubic meter. In fact asurprising one third of ice crystals in clouds were found to be nucleated biologically…”: B. Christner, 2012.
Related News:
Details :
Submited at Friday, August 10th, 2012 at 1:00 pm on Uncategorized by hilman
Comment RSS 2.0 - leave a comment - trackback