Linnaeus and the world of taxonomy

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Chordate: an animal with some type of central nervous system located on or near their back... more

Invertebrates: animals that do not have a backbone... more

Taxon: category or group such as phylum, order, family, genus, species... more

How Many Species Call Planet Earth Home?

This is a question that has not been answered, and it may never be known. There are estimates of the total number of species that reach as high as 100 million. What biologists do know is there are a lot more species we do not know about than the ones we have found and named. So far scientists have only discovered and named around two million species. This is why there are so many scientists exploring our world looking for undiscovered life.

You Can Be Part of the Adventure

The job is not a small one as you can see from the graphs below. There are millions of living things that need to be found and given a name. There are places where biologists are in a race against time and disappearing habitat. Even places like city parks and possibly your back yard could be home to a new species.

Graph of All Species

Click to enlarge.

Taking a closer look you can see how the search is going for Chordates.

Graph of Cordates

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There is even more work to be done with the invertebrates which include the world of insecta.

Graph of Invertebrates

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Becoming a Species Hunter

One of the best ways to learn about how to become a species hunter is to find a local group hosting a BioBlitz. These are 24 - 48 hour events where scientists and volunteers try to find and list all the living things in a given area. There are also special days each year when biologists and volunteers try to count all the birds, or butterflies they see in one day. These events are a perfect way to learn about living things and meet some of the people that are looking for new life every day.

BioBlitz - Auckland, New Zealand (gadfium / wikimedia).

A BioBlitz in Australia.

Graph data from: Biodiversity: Australian Biological Resources Study. 2nd Edition. September 2009. Retrieved May 22, 2010 from

View Citation

You may need to edit author's name to meet the style formats, which are in most cases "Last name, First name."

Bibliographic details:

  • Article: How Many Species Are There?
  • Author(s): Ruth Kearns
  • Publisher: Arizona State University School of Life Sciences Ask A Biologist
  • Site name: ASU - Ask A Biologist
  • Date published: May 21, 2010
  • Date accessed: May 15, 2024
  • Link:

APA Style

Ruth Kearns. (2010, May 21). How Many Species Are There?. ASU - Ask A Biologist. Retrieved May 15, 2024 from

American Psychological Association. For more info, see

Chicago Manual of Style

Ruth Kearns. "How Many Species Are There?". ASU - Ask A Biologist. 21 May, 2010.

MLA 2017 Style

Ruth Kearns. "How Many Species Are There?". ASU - Ask A Biologist. 21 May 2010. ASU - Ask A Biologist, Web. 15 May 2024.

Modern Language Association, 7th Ed. For more info, see
X-ray tetra, Pristella maxillaris

The amazing X-ray fish, or X-ray tetra (Pristella maxillaris). This chordate has a see-through body so you can look at its backbone.

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