Article curated by Ginny Smith
Scientists try to catalogue the world's species, but with huge areas still unexplored this is a difficult task. As more and more species become endangered and risk going extinct, it is a race against time to document the world's biodiversity, before it is too late.
Even in well explored areas, new species regularly crop up, like the new crayfish discovered recently in Tennessee. Scientist can guess at how many undiscovered species there are out there, using mathematical models, but it isn't clear whether we will ever have a complete picture of the animals and plants that exist here on earth.
Learn more about How many species are there?.
While finding new species is interesting for it's own sake, there are other reasons scientists are keen to explore them. Many of our medicines and everyday materials have been developed from natural sources.
Aspirin, for example, was originally extracted from the bark of a willow tree. We just don't know what other useful substances might be hiding in unexplored regions of the world, and what benefits they might have for humanity.
When we talk about how 'old' a species is, there are two things we can mean. Firstly, we could mean how long the species as a whole has been around- for example when the ancestors of animals alive now first walked the earth. Unfortunately, the fossil record is incomplete, meaning we have no way of knowing when certain species first appeared. Hopefully, as more species are discovered, either alive or in fossil form, we will being to be able to fill in the gaps.
The other possibility, when asking how old a species is, is that we are referring to how long an individual of that species lives. This is important, as studying long-lived animals may provide a clue into how we could slow down the aging process and even increase our lifespan.Without knowing all the species that exist, however, it is impossible to determine which lives to be the oldest, so we may not be investigating the most illuminating creature.
Learn more about aging.
This article was written by the Things We Don’t Know editorial team, with contributions from Zen Faulkes, and Johanna Blee.
This article was first published on 2015-08-27 and was last updated on 2016-12-22.