What is Extinction?
Extinction occurs when the last existing member of a given species dies.
In other words…there aren’t any more left!
It is a scientific certainty when there are not any surviving individuals left to reproduce.
Functional Extinction
is when only a handful of individuals are left, and the odds of reproduction are slim.
Coextinction
The loss of one species leads to the loss of another in a chain effect. A small impact in the beginning of an extinction can have an overall larger effect. Reasons for coextinction could be as a result of a predator losing its food source or if a key species becomes extinct and the ecosystem becomes off balance.
Mass Extinction
Aka: an extinction event
that destroys many species at once
- A sharp decrease in the number of species on Earth in a short period of time
- Coincides with a sharp drop in speciation
- The process by which new biological species arise
- There have been at least 5
mass extinction events with the mosts recent being 65 million years ago with the dinosaur extinction
Mass Extinction (cont.)
Mass Extinction
Nearly 2/3rds (or more) of all animal species that ever existed on the planet are now gone.
With contemporary extinction being attributed to HUMAN activity.
Numerous factors go into the extinction of a specific species.
Though all point the finger to climate change.
Mass Extinction
Began about three-million years ago (Continental Glaciations).
Hypotheses for initial extinction:
Sea level depletion vs. Temperature decrease
Though these hypotheses aren’t mutually exclusive, they may have conspired together.
Mass Extinctions
1.Cretaceous-Tertiary Extinction (65).
2.End Triassic Extinction (200).
3.Permian Triassic Extinction (250).
4.Late Devonian Extinction (364).
5.Ordovician-Silurian Extinction (440).
(#= millions of years ago)
Planned Extinction
Human controlled
extinction were thought to be helpful for the human population but generally ended in the spread of deadly viruses
- Smallpox- extinct in the wild
- Polio- nearly extinct but can be found in some parts of the world
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