27 August, 2011

How many complex species are there on Earth?

About 8.7 million.

And how many have we found to date?

About 1.2 million.

That is according to a recent study in PLoS Biology:

Knowing the number of species on Earth is one of the most basic yet elusive questions in science. Unfortunately, obtaining an accurate number is constrained by the fact that most species remain to be described and because indirect attempts to answer this question have been highly controversial. Here, we document that the taxonomic classification of species into higher taxonomic groups (from genera to phyla) follows a consistent pattern from which the total number of species in any taxonomic group can be predicted. Assessment of this pattern for all kingdoms of life on Earth predicts ~8.7 million (±1.3 million SE) species globally, of which ~2.2 million (±0.18 million SE) are marine. Our results suggest that some 86% of the species on Earth, and 91% in the ocean, still await description. Closing this knowledge gap will require a renewed interest in exploration and taxonomy, and a continuing effort to catalogue existing biodiversity data in publicly available databases.

Here is a table from the paper (click to enlarge) showing the vast difference in the numbers of catalogued and predicted species, which really highlights how little we know about life on our planet (particularly in the ocean).

An interesting calculation made in the study was the approximate cost and man power it would take to catalogue all of the species that are currently unaccounted for:

Considering current rates of description of eukaryote species in the last 20 years (i.e., 6,200 species per year; ±811 SD; Figure 3F–3J), the average number of new species described per taxonomist's career (i.e., 24.8 species, [30]) and the estimated average cost to describe animal species (i.e., US$48,500 per species [30]) and assuming that these values remain constant and are general among taxonomic groups, describing Earth's remaining species may take as long as 1,200 years and would require 303,000 taxonomists at an approximated cost of US$364 billion.

On the subject of species diversity, here is a nice 'tangled bush' image (click to enlarge then zoom in):


23 August, 2011

Skeptical Twitter community brings down internet spammer

See here for an excellent summary of the history behind the recent arrest of internet spammer and sender of death threats, Dennis Markuze (aka David Mabus).

The kook pictured below has spammed the inbox of hundreds of skeptical bloggers for years, starting off with relatively harmless verbal diarrhea, but becoming more and more sinister in recent times. His downfall came when he moved his tirade of abuse to Twitter, following which he (presumably unknowingly) began to harass the Montreal police department. The skeptical Twitter community then launched a petition to get the Montreal police to investigate Markuze. It worked. He was arrested and now faces 16 separate charges, and is currently undergoing a 30-day psychological evaluation.

What a moron.


22 August, 2011

Still no Higgs

Apparently the Higgs boson has not been found in the energy range predicted to be most amenable to its detection, casting doubt on its existence. The search now moves to lower and higher energy ranges, in which Higgs is less likely to be found.

According to James Gilles, the director of communication for Cern, it is now that the real work starts.

"In some mass areas, the Higgs is much easier to see than in others so in some mass areas it was always going to be easier to find it or exclude it quite quickly," he told BBC News.

"And now what we're being left with is the harder part; the regions where it's harder for us to see and harder to pick out the signal from the background."

The ranges left after these results suggest that the Higgs is either quite a light particle, below about 145 GeV, or a heavy one, above 466 GeV. A couple of islands in the middle, around 250 GeV, have not been fully excluded yet.