Bio30Quiz_Lectures16,17,18,19 Flashcards
Who 1st proposed EXTINCTION?
Georges Cuvier
1769-1832
Who was the 1st serious PALEONTOLOGIST?
Georges Cuvier
Who was GEORGES CUVIER?
- 1st to propose EXTINCTION
- 1st serious PALEONTOLOGIST
- supposedly could reconstruct any animal with just ONE of it’s bones
- demonstrated that fossil organisms were sig. diff. 4m modern organisms
xx.x% of all species that have ever lived are extinct.
99.9
What are the causes of EXTINCTION?
- DISEASE/EPIDEMIC wipes out a species
- CLIMATIC CHANGE occurs & species can’t adapt
- NEW SPECIES appear–out competes orginal species for resources
- ENVIRONMENTAL CATASTROPHE occurs
When did DINOSAURS go EXTINCT?
65 MYA
Why did DODO BIRDS & PASSENGER PIGEONS go EXTINCT?
Because of HUNTING PRESSURE
Where is Guam located?
It is a small island below Japan.
Where did the Brown Tree Snake come from?
Australia
How did the 1st pregnant Brown Tree Snake get to Guam?
A crate full of military supplies that was unloaded in Guam in WWII.
How many species of birds were eradicated by the Brown Tree Snake?
9 species, 5 of which were endemic
How do Brown Tree Snakes affect humans in Guam?
- venomous..many snake bites per year
- easily adapt to urban settings
- crawl into homes
- crawl onto Powerlines & cause power failures
- poultry quickly eaten, thus difficult to raise poultry
How many Brown Tree Snakes are estimated to be on Guam?
2 million snakes
that’s 14,000 snakes per square mile-highest density in world
What are some of the effects of the loss of birds on Guam?
Increased number of SPIDERS–the new predators of insects
What is being done to reduce effects of Brown Tree Snakes in Guam?
- 6,000 snakes trapped/year
- birds being CAPTIVE-BRED for eventual release to Guam
What is the GASTRIC BROODING FROG?
- found in 1973 in N.Australia
- swallows its eggs, they develop in stomach, frog spits them out
- not seen since 1981 due to habitat destruction & feral pigs introduced
What are MASS EXTINCTIONS?
When more than 50% of all life on Earth is wiped out.
How many MASS EXTINCTIONS have there been in Earth’s history?
at least 5
Which are the 2 most prominent Mass Extinctions?
Permian/Triassic
&
Cretaceous/Tertiary
Permian/Triassic Mass Extinction
- 248 MYA
- 95% of all life went extinct
- majority of species affected were marine organisms including Trilobites (54% of families of organism lost)
What (probably) caused the Permian/Triassic Extinction?
- Global cooling
- Formation of the super continent Pangea
- Glaciation at poles but Severe Warming & Cooling Cycles at Tropics & in Temperate Regions
- Massive volcanic eruptions in today’s Siberia
- Impact of a comet or asteroid
Cretaceous/Tertiary Extinction
- 65 MYA
- aprrox. 75% of life went extinct (17% of all families of organisms went extinct including dinosaurs)
What caused the Cretaceous/Tertiary Extinction?
- impact of comet or asteroid
- massive volcanism in today’s India
- BOTH EVENTS REDUCED PHOTOSYNTHESIS BY BLOCKING THE SUNLIGHT VIA DUST OR ASH
What is the IMPACT THEORY?
Crater found in Yucatan Peninsula, Mexico–150 miles with age of 65 MYA, probably from a COMET
- Can cause GLOBAL FOREST FIRES b/c atmosphere would be heated by several
- hundred degrees
- dust thrown up would reduce solar radiation, stop photosynthesis
- food chains would collapes
