Monday, January 24, 2011

A new ancestry for elephants

Changes in names and taxonomical classification are a common occurrence as our knowledge of species living and extinct expands. In fact, around 10% of all taxonomic names are changed every year (Nimis, 2001). The changes are mainly in the realm of microbiology where morphology is difficult to apply, but rarely in the realm of charismatic megafauna, e.g. elephants.

However, there has been a long ranging dispute on whether the African savannah elephant and the African forest elephant are merely subspecies of the African elephant (Loxodonta Africana), or whether the genus Loxodonta needs to be re-organised.

Recent work by Rohland et al. (2010) compared genetic markers of the genomes of the iconic woolly mammoth (Mammuthus primigenius) and the American mastodon (Mammut americanum) with the modern African savanna elephant, African forest elephant, and Asian elephant.

A surprising finding from our study is that the divergence of African savanna and forest elephants—which some have argued to be two populations of the same species—is about as ancient as the divergence of Asian elephants and mammoths. Given their ancient divergence, we conclude that African savanna and forest elephants should be classified as two distinct species.
As we see, there is no certainty in taxonomy. And there goes my favourite example of a stable taxonomic name.


Nimis, P. L. (2001), A tale from Bioutopia - Could a change of nomenclature bring peace
to biology's warring tribes?, Nature, 413(6851), 21, doi:10.1038/35092637.

Rohland N, Reich D, Mallick S, Meyer M, Green RE, et al. (2010) Genomic DNA Sequences from Mastodon and Woolly Mammoth Reveal Deep Speciation of Forest and Savanna Elephants. PLoS Biol 8(12): e1000564. doi:10.1371/journal.pbio.1000564

Tuesday, January 11, 2011

EarthObserver as iPhone App

Columbia University recently published yet another earth science application for Apple's iPhone. The app is called EarthObserver and is available from Apple's iTunes store. EarthObserver provides

  • Basemap (computer-generated color-shaded relief of land and ocean floor)
  • US Coastal Bathymetry (with color palette appropriate to provide details of bays, sounds, estuaries, harbors and rivers)
  • US Nautical Charts (paper raster and digital electronic at all scales for Atlantic, Pacific, Gulf of Mexico, Bering Sea, Arctic and Great Lakes)
  • US Topographic Sheets (entire USGS collection for US mainland, Alaska, Hawaii and Puerto Rico)
  • Geologic Maps (entire world, by continent, by country and by US state showing formation ages, names and rock types)
  • Geophysical Maps (global earthquakes, tectonic plates and boundaries, gravity anomalies, geoid height, magnetic anomalies and the configuration of world stress)
  • Land Surface (temperatures day and night, primary productivity, vegetation index, land cover classifications and diversity, forest cover types and fragmentation)
  • NASA Visible Earth (global earth scenes for each month)
And many more. See EarthObserver's homepage for more information.