Sixth Extinction Chapter 1 Flashcards
What is the focal species of chapter 1? Common and scientific name
Panamanian golden frog, Atelopus zeteki
What did the herpetologists say about the disapearing amphibians?
That based on extinction rates among amphibians, an event of similarly catastrophic nature was taking place (when compared to a mass extinction)
What are the 5 mass extinctions in earths history?
- Late Ordovician
- Late Devonian
- End Permian “great dying”, largest mass extinction
- Late Triassic
- End-Cretaceous
What is EVACC?
The El Valle Amphibian Conservation Center
What is EVACC’s purpose? Some features of it?
EVACC is essentially storing amphibians to keep species alive as they are at risk of extinction in their natural habitat.
EVACC must remain free from the chytrid fungus and thus everything entering has to be sterilized.
How/where was the chytrid fungus noticed?
First noticed in a zoo in Washington D.C., where poison dart frogs were being bred in captivity, when the frogs started to die, it was found to due to the chytrid fungus.
The dead frogs were put through an electron scanning microscope where the fungus was found on the animals skin.
How does the chytrid fungus kill amphibians?
The fungus interferes with the frog’s ability to take up critical electrolytes through the skin, which essentially causes the frogs to suffer from a heart attack
What is the abbreviation for the specific species of chytrid fungus affecting frogs?
Bd (Batrachochytrium dendrobatidis)
What are some of the phrases used to describe a mass extinction?
Mass extinctions are events that eliminate a “significant proportion of the worlds biota in a geologically insignificant amount of time”
“Substantial biodiversity losses”, that are “global in extent”.
What are the two theories for how Bd spread across the planet? Explain each
The “Out of Africa” theory and the “frog-leg soup” theory
The first theory is that global shipments of the African clawed frog (used as pregnancy tests in the 50’s and 60’s) spread Bd.
The second is that introduction of American bullfrogs (for human consumption) spread Bd
Both the African clawed frog and American bullfrog are carriers of Bd, but themselves are not harmed by it.
Describe “background extinction”
What is the background extinction rate for mammals?
Extinction only takes place very rarely, and occurs at what is known as the background extinction rate.
This rate varies from one group of organisms to another, and is often expressed in terms of extinctions per million species-years.
For mammals, the background extinction rate is about .25 per million species-years
