Explain how exotic species can threaten an ecosystem?

Question

I need to know this by tommorow for my final so anyone who gives me the answer gets 10 points!!

Answer 1

Exotic plants & animals have few or no natural enimies and if left unchecked will consume an ecosystem killing off anything that lives on what the exotic p&a feed upon. Examples such as killer bees in america killing off most of the natural bees in the area that have been polinating plants for years now have died and the plants they ounce polinated are going exstinct. Zebra muscles if left unchecked, brought to america from overseas boats, would take over the waters of america. Austrailia has been hit hard by many exotic creatures like king toads, mice, and pigs that defistate the food supply for natural animals and go mostly unchecked as they have no natural enemies. Animals that attempt to feed upon the king toads die because of their poison.

Answer 2

purple loose strife a flower that gets into wet lands and takes over the area forcing out native plants and animals till the wet land is no more

zebra mussels grow around intake water pipes and can clog it preventing water to access the pipe also very sharp they grow around docks and swimming areas can slice your hand or foot open

starlings introduced to New York central park in the 1800's  the starlings have contributed to the loose of breeding area for the Blue Bird in nature they are more aggressive for the nesting sites

Dutch Elm Disease introduced to N America after WW 1 has virtually wiped out the native elm tree population of N America also look up Chestnut Blight

Asian Ash Borer more resent invader killing of the ash tree populations of upper NY state and South western Ontario

these are just a sampling of introduced organisms that have been introduced to the N American ecosystems with devastating results

Answer 3

easy question, by exotic, meaning "not from there" it can totally ruin a ecosystem by consuming resources or killing some important link in the food chain or spreading diseases, the locals are not prepared to

It happened a lot in early years in Australia, when ships came, so came rats, with several diseases, they spread them all over local fauna, most of it was killed

when dogs entered, most Dingos (local dogs) loose territory and were forced away becoming fiercer and more aggressive

when rabbits entered, they breed quickly and become a plague that ate most of the crops

this list goes on and on ........

Answer 4

Exotic species are those species that are not native to the area, i.e.: ones that are brought in from another ecosystem and usually from another continent.  Exotic species can be beneficial or harmful so you must know something about their characteristics.

On the positive side: North Americans would have a very impoverished diet if exotic vegetable like tomatos and potatos etc had not introduced from places like Peru.

In Africa, almost all the tropical fruits are not native to Africa but imported as exotic species from India and Sri Lanka over the past several hundreds of years.  Some believe Africa did not keep pace with early development compared to Asia for example, due to the fact they had very few plant based food sources i.e.: very few vegetable and carbohydrate food sources until the introduction of exotic food crops.

On the negative side, a certain country I will not name, introduced (with positive intentions) a particular exotic thorny plant to help fight desertification in north eastern Kenya.  The idea was to stabilize the desert region soils so that other plants could establish later on.  The result was disasterous as the plant turned out to be much more invasive (i.e.: fast spreading) than in its native country.  Now thousands of square km are covered with this plant. The needles get caught in the throats of cattle and the plant is so prolific that humans cannot easily talk on much of the land where this exotic plant has 'taken over'.