Flashcards in Extinction Deck (68)
Extinction in the Holocene era (10,000 years ago)
Largest ground sloth was the size of an elephant.
Claws could reach 50cm in length.
Ground sloth was nothing like other animals, tiny head, slim shoulders and massive hind quarters.
Herbivores like their modern day tree sloth predecessors.
What is there a long term balance between
Rates of speciation and extinction
How can an equilibrium species richness be predicted
Based on rates of extinction and speciation among existing species
How many species have evolved on earth over the last 3.5 billion years
What percentage of the 4 billion species have gone
What does the species we have today represent
A very small proportion of what has been living in the planet
How many mass extinctions has there been
5 so far
What are mass extinctions
Times when the earth loses more than three quarters of its species in a geologically short interval
What are the names of the extinction events
How much did the Ordovician event lose
How much did the Devonian event lose
How much did the Permian event lose
How much did the Triassic event lose
How much did the Cretaceous event lose
The main causes of the Ordovician event
Onset of alternating glacial and interglacial episodes
The main causes of the Devonian event
Global cooling followed by warming, tied to diversification of plants
The main causes of the Permian event
Siberian volcanism and global warming
The main causes of the Triassic event
Elevated co2 levels increasing temperature and ocean acidification
The main causes of the Cretaceous event
A meteor causing a global cataclysm and caused cooling . May have also been climate change before
What do mass extinctions account for
4% of total extinctions (background rate is high)
What do mass extinctions do
Disrupt overall development of diversity
What do survivors of mass extinctions tend to be
Generalists and opportunists
How long does it take after a mass extinction to recover biodiversity
10 million years
What is the lifespan of all species
What does the IUCN red list data say about extinction
27,000 species are threatened.
Why is speciation not a relevant time frame to ya
Because time frame for speciation isolation is longer than extinction
What are traits promoting survival
High genetic variability.
Traits promoting extinction
Low genetic variability.
Exploited by humans.
What are r species
Opportunistic pioneers. They have been selected for their ability to reproduce rapidly