Transcript Biodiversity part 2 ppx

Biodiversity
part 2
Vocabulary:
1. Endangered species – at serious risk of
extinction
2. Threatened species – likely to become
endangered soon
3. Extirpation – disappearance of a species from a
particular area, but not globally
The tiger has been extirpated from most of its original
range (p. 201)
4. Endemic species – found in one area and
nowhere else in the world
The Coastal Redwood is endemic to central California
and Oregon (p.215)
5. Living Planet Index
• Developed by the WWF and UN Environment
Program
• Summarizes population trends for a set number of
species that are closely monitored fro reliable data
• Tracks species decline
Between 1970 and 2005 the index fell by 30%
(p.208)
Causes of Biodiversity Loss:
1. Habitat loss and habitat fragmentation
This is the primary source of population
decline for 85% of mammals and birds.
• Siberian tigers are isolated in the
mountains of their former range, with
unsuitable populated areas in between
• Less then 1% of the original American
prairies remain, bird populations there
have declined by 90%
2. Invasive species –
non-native species whose populations increase
rapidly and displace native species
• Zebra mussels entered the Great Lakes on
cargo ships, and have caused billions of
dollars in damage (p.210)
3. Overharvesting – harvesting a population
faster than it can repopulate
• including hunting, fishing, and poaching
• Many fish species are currently in danger of
extinction due to overfishing
• Large animals with low reproduction rates are
particularly at risk (tigers, elephants, rhinos)
4. Climate Change has global effects on
biodiversity
• Extreme droughts are causing population
declines
• Melting sea ice has caused the polar bear to
become endangered. Less ice means they
must swim farther for food, sometimes
drowning. (p.211)
White Board Questions
1. What is the living Planet Index and what does
it suggest about current biodiversity trends?
it tracks species decline,
shows a 30% decline since 1970
2. What are 4 major factors affecting
biodiversity today?
Habitat loss, overharvesting,
invasive species, climate change
3. Which one currently has the greatest overall
effect?
Habitat loss
4. How is climate change different from the
other factors?
It is global
Protecting Biodiversity
Legal efforts:
1. US Endangered Species Act: (1973)
protects species that are endangered or threatened,
and the ecosystems on which they depend.
2. CITES (1975) Convention on International Trade in
Endangered Species:
prohibits the hunting and selling of endangered
species or their products
Species Survival Plans: manage, protect and
reintroduce to the wild
1. Captive breeding programs are carried out by zoos
and botanical gardens
2. Cloning - using a non-endangered species as a
surrogate mother
These programs increase the population but if their
habitat has been lost they can never be released
Habitat Approaches:
1. Biodiversity Hotspots - areas that have a high
number of endemic species and are rapidly loosing
biodiversity. (p.216)
Preserving Biodiversity Hotspots is critical
to preserving global biodiversity
2. Wildlife corridors –built to connect fragmented
habitats (p.217)