Final Exam: The Age of Humans and the "6th Extinction" Flashcards
What happened to animal species as humans began to colonize islands?
Animal species were going extinct
Humans arrived at most ______ in the more ______ past. Why?
islands; recent; because it’s harder to get there
What type of species mostly went extinct on islands after human arrival? Why?
Bird species; many flightless birds on islands which makes them very vulnerable
Why were there flightless birds on islands?
they didn’t need to use their wings anymore, so they saved energy by not flying and eventually became flightless
Why were extinctions easier on islands?
Smaller space
T or F: Extinctions have resumed on continents over past few centuries.
True
What animal is this:
- went extinct 1914
- lots of these birds in North America back then
Passenger Pigeon
What animal is this:
- went extinct 1918
- lots of these lived over large areas in North America back then
- targeted to be eliminated for eating farmer’s crops
Carolina Parakeet
compares modern extinctions to the “Big 5” in Earth’s history.
Sixth Extinction Hypothesis
Are We in a “Sixth Mass Extinction” Right Now? This depends on…
how you define a mass extinction, and what will happen in the future.
What is the challenge in determining if we are in a sixth mass extinction?
Proving if species are extinct; (some species, such as the ivory billed woodpecker, are secretive and it’s hard to determine if they’re extinct)
Why do some researchers say we are living through the “sixth mass extinction”?
The rate of extinction is high and it’s leading to a significant loss in biodiversity
Are more species going extinct now than in past mass extinctions? Are species going extinct faster or slower than in the past?
- Yes
- Faster than in the past
- What are the 4 parts of the Earth System?
- Are they all interconnected? Do humans have a global influence on the Earth System?
- Biosphere, Geosphere, Hydrosphere, Atmosphere
- Yes; yes
Humans are part of what part of the Earth System?
Biosphere
How have humans affected the biosphere? (2)
- created new forms of life through artificial selection
- extinctions
How have humans affected the geosphere?
- mining is moving massive amounts of rocks
How have humans affected the hydrosphere?
building dams → changing a river into a lake → affects evaporation and sediment deposition
How have humans affected the atmosphere?
Burning fossil fuels
a proposed new part of the geologic time scale defined by powerful global human influence.
Anthropocene
The Anthropocene would be an _____ of the Quaternary period.
epoch
T or F: The Anthropocene wouldn’t affect the geologic time scale how we learned it
True
Including the anthropocene, the Quaternary period would be epochs of ________, ________, and _________.
- pleistocene
- holocene
- anthropocene
- What time has been proposed as the start of the Anthropocene?
- Why (4 things)?
- 1950
1. Human population growth (over 8 billion people now)
2. Carbon Dioxide levels increase
3. Global temperature rises
4. Sea level steadily going up
_____ _______ are used to relate rock layers that are continents apart.
index fossils
What clues are we leaving behind in the rocks for future geologists to find?
Plastic, nuclear waste, footprints, etc.
Radioactivity from nuclear tests is detectable in ______ and ______ from 1950 onward.
sediment; corals
Why is plastic a good clue for future geologists to find that show our existence?
because there is no natural plastic in the world; it is human made.
where plastic is bonding sediments together
Plastiglomerates
could mark the start of a new Anthropocene epoch; proposed defining location
Crawford Lake in Ontario
Why did the Anthropocene get rejected?
because it’s tough to pinpoint when humans’ impact on the planet began.
