Extinction Flashcards
How is the rate of extinction currently?
while there are more species on Earth currently than at any other time, the rate of extinction is greater than that of any other time
What are the different kinds of extinction?
- in the wild
- globally
- locally
What percent of species that have existed on the planet are now extinct?
99%
How many mass extinctions have there been?
5 in past, not including the one we are currently in
What are the past mass extinctions?
- Ordovician
- Devonian
- Permian
- Triassic
- Cretaceous
What animals went extinct during Cretaceous?
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f
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Where have a lot of species gone extinct?
species on islands such as Hawaii
What vertebrate animals are threatened with extinction?
- primates
- manatees, dugongs
- horses, tapirs, rhinos
- turtles
- penguins
Have more mainland or island birds gone extinct?
drastically more island birds
What is the significance of St. Helena island?
a plant (St. Helena Ebony) thought to be extinct was rediscovered in 1980
How was St. Helena Ebony saved from extinction?
- was given endangered species status and saved from extinction
- cross bred with St. Helena Redwood, producing Trochetiopsis x benjamini
How did St. Helena Ebony originally dwindle in population to what led people to think it went extinct?
declined when goats brought to island in 16th century and believed to be extinct by 1850
How is the proportion of recently extinct/currently endangered bird species related to the length of time non-European people have occupied an island?
inversely related
What makes a species vulnerable to extinction?
- narrow geographical range
- only one or few populations
- small population size
- low population density
- large home range species
- large body size
- K-strategists (unable to rebuild pop. fast enough after disturbance)
- occupies only one or a few specialized habitats
- ineffective dispersers
- migrate
- little genetic variability
- specialized niche requirements
- characteristically found in stable environments
- form permanent of temporary aggregations
- hunted or harvested by humans
What are characteristics of common species?
- wide geographical distribution
- broad habitat specificity
- large local population size
What are characteristics of rare species?
- narrow geographical distribution
- restricted habitat specificity
- always small population size
Why does the cape region of South Africa have high percent of endemic species?
Chapparal biome
Why does Australia have a high percent of endemic species?
is an island
What things tend to have higher levels of endemism?
- closer to equator
- type of biome (Chapparal, tropics, etc)
- various habitats (like in GA)
Why is extinction a problem?
- extinct species are lost forever (loss of biodiversity and potential future utility)
- ecosystem processes disrupted (food web, loss of pollinator species)
- loss of inherently valuable organisms
Where was the Dodo found?
volcanic island of Mauritius (Indian Ocean)
What are some species that have gone extinct?
- Dodo
- Monteverde golden toad
- ## Wolly mammoth
