May 16 – Endangered Species Day

nPostednon May 16, 2014

Thenofficial website for Endangered Species Day offersndownloadable materials and a list of events. There is also a nicenslideshow of youth art about the theme. Check it out!

nTherenis a new TV show called “Extant” that I have seen advertisednrecently. I don’t know whether or not it will have something to donwith species survival, but the word extant is the opposite ofnextinct. Obviously, a speciesnis extinct if there is not one surviving organism of that speciesnalive. If you have one or two or hundreds or billions of that speciesnalive, it’s extant.

nButnwhat about the term endangered? How low do populations have to drop for a species to be categorized as endangered? Are there other criteria for an endangered species?

nThe criteria is way too complicated for me to accurately describe it here. However, I will provide some comparison

nExtinctn – Scientists only call a species extinct when there have beenn careful surveys of the creature’s known habitat at the appropriaten time of day and year, and such widespread, long-lasting surveysn leave no reasonable doubt that every last creature has died.

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nExtinctn in the wild – When an population of organisms has been collected by zoos or rescuen organizations in an effort to protect and breed them, usually withn the hope that they can be reintroduced back into the wild – andn when the exhaustive survey described above turns up no other membersn of that species, it is considered extinct in the wild.

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nCriticallyn endangered (possibly extinct)n – This unofficial category is used by some scientists when theren are still unconfirmed sightings of a creature, or when there haven not yet been widespread surveys to confirm a feared extinction.

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nCriticallyn endangered – Then criteria is too complex for me to represent accurately here, but In can give you some idea: if the population of a creature has droppedn 90% over the past ten years, and seems to be still dropping, and/orn there are fewer than 50 mature individuals still alive, and/or then chances of extinction over the next decade are 50% or more, it’sn likely categorized as CE.

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nEndangeredn – This is more along the lines of a 70% drop over the past decade,n and/or fewer than 250 mature individuals, and/or the likelihood ofn extinction in the next decade is about 20%.

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nVulnerablen – Around 50% population drop, and/or population of fewer than 1000n mature individuals, and/or the chance of extinction in the wild isn estimated at 10% within the next decade.

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