By: Mary A. Rodrigues
The Accelerating
Loss of Species:
The Sixth Extinction
Mass Extinctions
A Mass Extinction is: When at least half of all species (including animals and
plants) die within a relatively short time. We know these extinctions occurred
Through the fossil record Fossils of plants and animals in early layers are suddenly
not present in later rock layers Scientists believe that 99% of all plant and animal species that have
ever lived are now extinct
The First Five Extinctions
1st (Ordivician-Silurian) Extinction: 440 mya Caused by: sudden global cooliing Extinction of marine organisms
2nd (Denovian) Extinction: 370 mya Caused by: possible climate change Extinction of tropical marine species
3rd (Permian-Triassic) Extinction: 245 mya Caused by: climate change, plate tectonic movements,
possible comet or meteor impact. largest mass extinction (so far) Killed a range of species, including vertebrates Only 10% of species survived
4th (Triassic-Jurrasic) Extinction: 210 mya Unknown cause Extinction of land vertebrates
5th (Cretaceous-Tertiary) Extinction: 65 mya Caused by: collision of comet
or meteor and/or volcanic eruption
Extinction of dinosaurs, marine life, and many other plant and animal species
50-75% of animals extinct Global temperature decreased Rise of the primates
How is the Sixth Extinction Different?
The sixth extinction is happening today All other mass extinctions were caused by
natural disasters, the sixth extinction is being caused by modern humans
When did the Sixth Extinction begin? When modern homo sapiens
began to radiate to different parts of the world.
Only in places where early hominids lived, (Africa, Europe and Asia) did native plant and animal species survive in the beginning.
Some paleoanthropologists believe that the Neanderthals became extinct due to warfare or competition from modern humans.
Quickly after the arrival of modern humans, native species began to disappear.
North America – 12,500 years ago
Butchering killed off mammoths, mastodons, ancient buffalos
Caribbean – 8,000 years ago Lost all larger native
species Madagascar – 2,000 years
ago Lost larger lemurs, elephant
birds, a species of hippo, etc.
How are modern humans causing the Sixth Extinction?
1. Pollution
2. Warfare
3. Exploitation of
Species
4. Overpopulation
5. Unnatural Rates of Consumption
6-Agriculture“Single most profound ecological change in the entire 3.5 billion history of life”(Eldredge,N.)
- Pre-agricultural humans lived in niches in ecosystem and
worked with nature.
-Agriculture was invented 10,000-12,000 years ago in the Middle East
- Agricultural humans live outside the natural ecosystem.
-Accelerated rates of extinction Humans do not have to rely on other species for survival Humans do not have to rely on ecosystem’s carrying
capacity (how many species a local habitat can sustain)
Agriculture (continued)
Results in:
Modern Humans living outside the natural
eco-system
Treating native plants as weeds
Treating native animals/insects as pests
The Sixth Extinction: Specifics
30,000 species are lost annually (3 species an hour)
Up to 1/5 of all living species could become extinct within 30 years
Nearly all loss is due to human activity Mostly through the destruction of plant and animal
habitats
What can we do to help?-get informed-get involved
http://www.well.com/~davidu/extinction.html http://en.wikipedia.org/wiki/Mass_extinction http://en.wikipedia.org/wiki/Sixth_extinction http://images.google.com http://www.amnh.org/exhibitions/dinosaurs/
extinction/mass.php Park, M. (2002). Biological anthropology. 3rd edition.
Boston:McGraw-Hill.
The Great Apes:
Their Battle Against Extinction
By: Angela Rodrigues
What is the Status of the Great Apes?
Chimpanzees: 150, 000
Bonobos: 50,000-100,000
Gorillas: 130,000 (wild), 350 (captive)
Orangutans:12,000-15,000 remaining in Borneo
Chimps, Bonobos, and Gorilla Distribution: Africa
Orangutan Distribution: Asia
Chimpanzees/Bonobos: Status: Endangered
1. Habitat Loss: Human population increase;
Africa has highest growth rate in world!
2. Biomedical Research: Used as “models” for human
diseases; 99% similar DNA
3. Disease: HIV Ebola
4. Hunting: Bushmeat Trade
Fact: The only true threat to Great Apes are humans
Gorillas: Gorilla gorillaStatus: Critically Endangered
1. Habitat Loss: Deforestation-Competition for
natural resources
2. Disease: Ebola
3. Poaching: Not for food Traps for other animals
Threats:
Orangutan: Pongo pygmaeusStatus: Critically Endangered
1. Habitat Loss: Palm Oil Plantations:
“Slash and Burn”-a process of clearing areas for agriculture by setting it on fire.
Logging: 80% is done illegally
2. Pet Trade Infant’s mother killed to obtain baby. 4-5 orangutans die for every baby
reaching the market
3. Poaching Bushmeat
Bushmeat Trade: #1 Threat
Over 1 million metric tons of bushmeat are distributed per year in Africa—not all are Great Apes, however.
No longer is this done just by poor locals needing food/income; it is becoming a commercial business
40-60% of Africans rely on bushmeat for source of protein Not just a Great Ape problem; many endangered animals, such as
leopards and elephants, are also killed yearly.
What Does Their Future Hold?
Some Statistics:
For every 20,000 humans, there is one chimpanzee
It is estimated that apes may become extinct within the next generation
Some estimates even say that some species may be extinct as soon as 5-10 years!
The bottom line: People need to be educated about the seriousness of the Great Ape Extinction
We started this extinction: it is up to us to end it.
If we don’t help, who will?
References:
1. Great Apes in Peril (2001). BBC World News. Retrieved May 1, 2006, from http://news.bbc.co.uk/1/hi/sci/tech/1341609.stm
2. The BushMeat Trade (2005). Retrieved May 1, 2006, from http://www.rainforestlive.org.uk
3. Chimpanzee Conservation (2006). The Jane Goodall Institute. Retrieved April 27, 2006, from http://www.janegoodall.org/default.asp
4. Primate Info Net (2005). Retrieved April 26, 2006, from University of Wisconsin-Madison: http://pin.primate.wisc.edu/about.html
5. Orangutan Conservancy (2006). Retrieved April 26, 2006, from http://www.orangutan.com/orangutans_threats.html
6. Great Ape Project (2006). Retrieved May 1, 2006, from http://en.wikipedia.org from Wikipedia.
7. Threats to Gorillas (n.d.). Retrieved May 26, 2006, from http://www.mountaingorillas.org/gorillas/gorillas_threats.htm
8. Park, M. (2005). Biological Anthropology (4th ed.). New York: McGraw-Hill Companies.