STUDY GUIDE COMPREHENSIVE
QUESTIONS ANSWERS VERIFIED A+
◉ What is mass extinction?
Answer: A decline in biodiversity greater than the background extinction
rate
◉ What is background extinction?
Answer: Background extinction occurs when certain populations are
reduced to zero because of normal environment change, emerging
disease, predation pressure, or competition with another species
◉ How are mass extinctions detected and how many have been
detected?
Answer: They're detected geologically, and there have been 5 detected
◉ What organisms became extinct during the Pleistocene and
Cretaceous and what are possible causes for these extinctions?
Answer: Pleistocene: Wooly Mammoth, Giant Short-Faced Bear, Dire
Wolf, Giant Beaver, Shasta Ground Sloth, American Lion
-Could be extinct because of climate change (warmer temps), human
overkill (predation), pathogens
Cretaceous: Dinosaurs
-Could be extinct because of asteroid (impact hypothesis)
,◉ What is the evidence to support that there will be a 6th mass
extinction?
Answer: Modern rates of extinction are 100 to 1000 time greater than
the background rate
◉ What is overexploitation?
Answer: -Any unsustainable removal of wildlife from the natural
environment by use of humans
-Harvesting of organisms at rates exceeding the species ability to replace
itself
-The dominant threat to marine species
-Overhunting
◉ What is habitat destruction?
Answer: Terrestrial Ecosystems: Conversion agriculture, logging,
development and urbanization
Aquatic Ecosystems: Draining and developing wetlands, damming rivers
Species area curve - As the land area decreases, the number of species
decreases
◉ What is habitat fragmentation?
Answer: -The breakup of large pieces of natural habitat into small,
isolated pieces
-Can reduce a habitat to where it's too small to support a species
, -Reduces the ability of individuals to disperse from one habitat to
another (could be more vulnerable to catastrophes)
-Creates a large amount of "edge" habitat (Edge effects light levels,
pollution, poachers, and competition)
-The species most impacted by this are those that require large territories
to find food
◉ How can an exotic species contribute to extinction?
Answer: -An introduction of a new species, that could possibly become
an invasive species
-An exotic species could carry pathogens
◉ What are phenology shifts?
Answer: *Related to global climate change*
-Timing of seasonal events
-Concern mismatch between organisms
◉ What are geographic range shifts?
Answer: *Related to global climate change*
-Organisms move into climates to which they're adapted
-Concern for organisms in arctic and alpine regions (running out of
habitat)
◉ What are consequences of extinction?