2. Invasive Species
“An alien species whose introduction
does or is likely to cause economic or
environmental harm or harm to human
health…”
“ „Alien species‟ means, with respect to a
particular ecosystem, any species that is
not native to that ecosystem.”
4. Disease
Invasive species bring diseases not native
to the ecosystem
Detrimental to native species with no
immunity
Example:
Asian chestnut blight fungus
180 million acres of forest destroyed
Moth species living in chestnuts became
extinct
5. Predators
Reduce population sizes
No evolved defenses
Extinction
Example: Brown Tree Snake
Introduced to Guam through ship cargo
Eliminated 10 of 11 species of bird species
6. Competition
Invasivespecies are more efficient
Native species are not as well adapted
Example: North American gray squirrels
Introduced to Great Britain and Italy
Driving native red squirrels to extinction
Forage for nuts more efficiently
7. Hybridization
Members of two different species mate
and successfully reproduce
Invasive species is more abundant
Genes “flood” the native species
Forces extinction
Genotype of native species phased out
No selection for reproductive isolating
mechanisms
9. Zebra Mussels
Brought to U.S. (Great Lakes) from Russia
in ballast of ships
Filter large amounts of water
Reduce densities of planktonic organisms
Settle in dense masses over expansive
areas
30 freshwater mussel species threatened
with extinction by competition
15. Pollution
Chemical pollutants
Pesticides
SO2, CO, nitrogen oxides
Changes metabolism
Chemical imbalances
16. Spread of Disease
Bringdiseased animals from one place to
another and infect native populations
Bird flu
Swine flu
Self invasive species
Spread diseases across human populations
17. Spread of Diseases
Hawaiian Islands
Habitat fragmentation
Habitat destruction
Alien species
Diseases
19. Habitat Destruction
Development of
Infrastructure
Agriculture
Deforestation
Waste dumping
#1 cause of species extinction
20. Habitat Destruction
In Europe, >85% natural habitat destroyed
for agriculture
California coastal wetlands shrunk by 90%
over 150 years
98% usable agricultural area on Earth
already developed
21. Deforestation
48% - Subsistence agriculture in poor
countries
32% - Commercial agriculture
14% - Commercial Logging
6% - Charcoal and other fuel wood
removal
23. Deforestation
The Tropical Rainforests
Contain 50% of all 10 million species of
plants, animals, and insects
50,000 disappear annually due to
deforestation
“Lungs of our planet”
24. Deforestation
The Amazon Rainforest
If destroyed, U.S. greenhouse gas emissions
would increase 50 fold
90 indigenous tribes destroyed
Loss of…
Medicinal knowledge of plants, trees, and other
species
Great economic value if sustained
30. Extinction
Main reason
Human overpopulation of the earth
Extinction rate of species accelerated
starting 1600 AD
80% of all extinctions due to habitat
destruction by humans
32. We suffer
We pose a threat to future generations
We have negative effect on them, but
they have no effect on us
Must maintain the earth for the future
We are the greatest threats to ourselves
33. In Conclusion…
Invasive species are a danger to many
different ecosystems
Humans are the most invasive species
What must be done?
Maintenance
Education
Reforms
Protection of ecosystems
34. Sources
"FARM: Farm Animal Rights Movement." The Cost of
Disappearing Rainforests. Google Blogger, 14 Oct
2010. Web. 21 Nov. 2011.
Hogan, C Michael. ”Causes of Extinction." Encyclopedia of
Earth. 2010. Web. 21 Nov 2011. <http://
www.eoearth.org/article/Causes_of_extinction?
topic=58074>.
Hogan, C Michael. “Deforestation.” Encyclopedia of Earth.
2010. Web. 21 Nov 2011. http://www.eoearth.org/
article/Deforestation?topic=58071
McGinley, Mark. "Invasive species". Encyclopedia of Earth. 2010.
Web. 21 Nov 2011. http://www.eoearth.org/article/
Invasive_species?topic=49513.
