beetles. There are also 12,000 species of ants, and over 1,000 species of bats, and so on for other creatures. (Further counts here.
My question is: who in the world counted up all these species? I could imagine if there were 7 species of something, you could get some people with the time and inclination to count them all up, and catalogue the specific characteristics of each. But how could anyone possibly figure out that there are this many species? What kind of manpower has to be involved in going through what must be millions and millions of individual creatures, observing them for characteristics that must then be compared with those of thousands (or hundreds of thousands) of other species to make sure that the species is ne, and so on?
The whole thing seems strange. (Is it possible that there are not really all these species that are known to be unique species but that someone has speculated that there would be based on some scientific principle? Unlikely, I imagine, but you never know.)
IANAE (I am not an entomologist) but: entomologists go out into the wild, find beetles, etc., examine them, and compare them with published descriptions. If the species has not yet been described and published, they submit an article to a journal, the article is reviewed and published, then indexed in indexing journals, and referred to in new textbooks on beetles. Then more entomologists go out into the wild, and the process is repeated. This process has been going on for at least 200 years.
Yes, there’s a lot of manpower involved. And the count is partly done by the people who write the textbooks on beetles, after reviewing all the journal literature.
Based on the Wikipedia article you linked to, those numbers are estimates. These are probably based on extrapolations from actual numbers of described and named species. One of our forum mods, Colibri, is a biologist. I hope he’ll stop in and expand on this.
Someone goes out into the forest, jungle, garden, whatever, and spots a bird, insect, whatever, that he’s never seen before. He writes a very detailed description of it, and maybe even a bunch of photos. Then it flies or runs away. A while later, I read in the newspaper about his having discovered a new species. (This happens all the time. I hope I don’t really have to give citations. But I will if anyone insists.)
How can someone be sure, from such a fleeting observation, that this is a new species, and not simply an oddly-colored or oddly-behaved individual from some other species?
Let’s take beetles for an example. The number cited is an estimate of all the species that have so far been described and named by scientists, not an estimate of the total number of species of beetles that exist in the world.
The effort for beetles has taken thousands of scientists a couple of hundred years so far. Of course even the most prolific beetle taxonomists (scientists involved in classification) have probably described no more than a few hundred, maybe a few thousand species each.
Taxonomists of course don’t need to compare what they think may be a new species with “millions and millions of individual creatures.” They will ordinarily be able to recognize that the unknown form belongs to a particular family on the basis of its characteristics, and may even be able to determine what known species it most resembles. The description then just becomes a matter of determining which characteristics differentiate it from related species.
Most insect taxonomy (and in fact most taxonomy in general) is carried out by specialists in a particular family, subfamily, or even smaller group. They are familiar with the scientific literature on a group, and able to recognize most known species, so they know when something may be new.
There may be problems, however, because it may be necessary to compare the new specimens with the type specimens on which the known species were based, and these may be scattered in museums throughout the world. Earlier descriptions in the literature may be vague or incomplete. There may not be enough specimens to be sure that any differences are consistent, and not just individual variation.
Taxonomists sometimes disagree on whether two slightly different forms belong to different species or not. Also, sometimes the same species may be described under two different names, because a scientist was not aware of a previous description in an obscure journal, or was not able to compare his sample with specimens in other museums.
So the total number of described species in most large groups are estimates, since there may be differences in opinion on some species, and some duplication of names.
The total number of known species of beetles is estimated simply by totalling up the number in each family (and that is arrived at by totalling the number in each subfamily, genus, or species group within the family). These numbers are arrived at by consulting experts in each of the different groups.
Here is an example of an on-line taxonomic journal, Zootaxa, which will give an idea of the kind of articles that are published. There are many other taxonomic journals.
Estimates of the actual total number of species that may exist on the planet vary greatly based on various assumptions. At present, there are about 1.6 million species that have been named by scientists. Most scientists estimate that there are probably actually about 5-10 million species, though some have estimated 30 million or more.
It’s not uncommon for the same species to be discovered twice, fairly close together, so that the first discovery hasn’t permeated through taxonomic literature yet. Then you end up with one species with two names.
This happens even more often with fossils, where a find is classified as a new species because of sexual dimorphism or damage to the fossil and the like, and eventually has to be reclassified.
Paraceratherium, for example, has been “discovered” at least four times.
I did a quick search in Google News on “discovered a new species”. Okay, I concede that one needs more than just a quick look from a birdwatcher. But even with studying an actual live specimen, new species crop up so fast that it is difficult for me to accept that more than 10% of them are truly new.
You’re wrong. There are a lot of people doing this, and a very large number of unknown species to be described. Species descriptions these days are very meticulous, and published in peer reviewed journals. Type specimens must be designated, and deposited in a collection. (Up until recently, it was possible to publish a description based on a photo, but that’s no longer an option, and was rarely employed in any case.)
I am actually developing an exhibition on newly discovered species for a new museum of biodiversity under construction in Panama. For the exhibit, I asked an entomologist friend for specimens of beetles that had been collected but not yet described. In about 20 minutes of looking through the collections, he was able to give me specimens of 20 undescribed species. There were dozens more that he thought were new, but he didn’t want to give me the specimen because it was the only individual he had. The species were undescribed because no specialist had gotten around to looking at them in detail and writing them up yet. My friend knew they were new because he was familiar with the known species and could recognize they were different. (He’s been working on beetles in Panama for about 40 years.)
Birds are pretty well known, but I and several collaborators identified and described a new species of bird in Africa last year (a kind of forest robin). The description was based on collected specimens (which were compared with specimens of all known species in the genus), genetic analysis, recordings of calls, etc.
Don’t trust what you read in the newspaper. Every time I’ve given an interview to a newspaper, they’ve gotten something wrong. (One quoted me as saying there were 9000 species of birds in Panama, when I told them there were around 900.)
I note that the Guardian article on the same expedition was more conservative:
I think the Evening Standard just misinterpreted “hundreds of species” found by the expedition as “hundreds of new species,” and “new populations of birds” as "new species of birds.
This said, it would not be at all surprising, in visiting an isolated mountain forest in the tropics for the first time, to discover dozens of new species of insects and plants (and to be aware that they were probably new due to knowledge of what occurs on neighboring ranges). However, the actual description and publication will probably take years.
That’s what I was hoping to hear. Without genetics, I’d love to know how to tell the difference between a whole new species as opposedto variations within a species.
Ditto. But I hear about new species so often, from so many sources, that I’m very curious (and a bit suspicious) about how the whole process works.
If you were an extraterrestrial, cataloguing the species of this galaxy, how would you consider the many types of humans on this planet? Would ETs consider the Scandinavian Blondhead and the Australian Aborigine to be one species or two? Heck, I live here, and without genetics (i.e., ability to produce fertile offspring), I don’t know why we would consider a Chihuahua and a St. Bernard to be in the same species.
I meant in the course of establishing 350,000 species, you would need to look at millions and millions in aggregate, not that you need that many for each species.
What would you think are the total man-hours involved in documenting a single species, including field observations, study, research, write-up etc.?
It would seem from what you describe and the sheer number of species out there that a significant percentage of the world’s resources must be going into just documenting and keeping track of various species. (This suggests a possible solution to the current economic crisis … :D)
No, the reason there are so many new species discovered every year is precisely because so little effort is made on discovering new species. We’re talking about only a few hundred scientists. And they aren’t cataloging new species full time, they have to teach, write, do other research, keep up with the literature, secure funding, and so on.
And so you have the situation of Colibri’s colleague who has dozens of specimens of potential new species, but he doesn’t have the time to sit down and describe all of them because his other work is more urgent.
If you study mammals or birds then a new species is tremendously exciting. But if you study insects new species are so common that it is impossible for one person to keep up. They’re as common as dirt, anyone who has the time and funding can go to any tropical rainforest and come up with dozens of new species of insects.
Is there no complete list of the species anywhere? I mean, I am sure that for many small groups (say, elephants) there will be complete lists here and there, but isn’t there any form of World Escarabologist Association with a full listing of the beetle species? Are there that many lose lists around that they cannot be properly totaled and the best we can do is an estimate of described species?
That was pretty much my point. If someone finds what he thinks is a new species, he’s gotta mate it with all the likely candidates, and see which ones win? Sounds pretty labor-intensive, not to mention this poor little bugger may not last past next week.
But the biological species concept isn’t the only possible way to define a new species. In most cases captive breeding of the proposed new species is impossible. And the biological species concept requires that the members naturally interbreed. Lions and jaguars are different species, yet if you put a lion and a jaguar in the same cage you will sometimes get baby liguars. And those liguars are fertile, not sterile. So now what? Declare that lions and jaguars are really the same species, despite living on different continents, having different phenotypes, different habits, different social structures, and so on? And of course it breaks down completely when we look at asexual species.
The biological species concept is a useful way of thinking about what a species is, but it isn’t perfect.