Introduction and Extinction of Species in an Eco System Zebra Mussel

Species Introduction “Introduced species are species that have become able to survive and reproduce outside the habitat where they evolved or spread naturally.” -United States Environmental Protection Agency Example of an ecosystem

Introduced Species  Species can be classified in two classes 1)Invasive 2)Non-invasive  Both types of introduced species are brought to a new environment by human activity, either accidentally or deliberately. Example of an invasive species :Zebra Mussels

Definition of Non-Invasive Species  A non-invasive species is an organism that is not native to the ecosystem, but doesn't have any negative effects on the ecosystem.  Examples include peaches and tomatoes.

Definition of Invasive Species  An invasive species is an organism that is not native to the ecosystem, and has negative effects on the ecosystem.  Examples include the zebra mussel which originated in Russia, and are now found in rivers worldwide, and cause damage by clogging pipes and contaminating the water. A colony of Zebra mussels that are attached to a larger mussel

What do invasive species do, anyway, and why do they pose such a threat  Invasive species cause harm to wildlife that is foreign to it. These species are new which causes them to be more aggressive. The new species may not have any predators, and their numbers will spread rapidly and uncontrollably, along with taking over an area. Native wildlife wont be able to protect it’s self against the new invasive species

New Zealand

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Extinction Definition  The death of a species. It is considered to be the death of the last member of the species.  The two types of extinction are: Global Extinction Local Extinction

Global Extinction  Defined as the total disappearance of a species Examples include the Dinosaurs and the Dodo, both of which are extinct worldwide. Dodo Bird Extinct dinosaur

Local Extinction  Defined as the disappearance of a species in a certain ecosystem, but the species lives in a different ecosystem.  Local extinction can be fixed by replacing the missing organisms with the same species from other locations.  An example of local extinction is that saltwater crocodiles used to live in Vietnam, but are now extinct in that specific location. Salt water crocodile

Effects of the Extinction of a Species  If a species is eliminated, it will cause many problems with the other trophic levels. Everything that this species feeds on will become overpopulated and begin to die out, affecting the next trophic level, and so on.  This is called the cascade effect.

Practice

Questions  1) What is the definition of extinction?

 The death of a species

 What are the two types of Extinction

 Global and local extinction

 What are two examples of global extinction

 Dinosaur and Dodo Birds

 What is an example of local extinction

 Salt water crocodiles

 What are the two types of introduced species

 Invasive and non-invasive species