BIOL 180 Exam Concepts and Questions with actual
answers 2026\2027 A+ Grade
What is the most important difference between species richness and species diversity?
- correct answer Species diversity takes species number AND relative frequency into account.
What is the key difference between primary productivity and net primary productivity?
- correct answer Net primary productivity represents just the energy used to build biomass.
"Diversity leads to stability." This slogan claims that ecosystems with a large number of species present
are more stable than ecosystems with a low number of species. Which of the following lines of evidence
support this claim?
- correct answer As the number of plant species increases, resistance and resilience increases
What is biomass?
- correct answer total organic matter, usually measured per plant or per square meter
Why would a sampling effect lead to higher productivity in an experimental plot?
- correct answer If a few highly productive species are present in a community, biomass production will
be a function of whether or not they are present.
What is a functional group?
- correct answer Species that use resources or allocate resources in a similar way
In biological communities, what is "resistance?"
- correct answer degree of change during and after a disturbance
In biological communities, what is "resilience?"
- correct answer ability to "bounce back" after a disturbance, to the pre-disturbance conditiion
, What is a "natural experiment?"
- correct answer an unplanned/unmanipulated change in environmental conditions that can be
exploited to answer a question
What is the difference between climate and weather?
- correct answer Climate consists of long-term conditions; weather consists of short-term conditions.
What causes the Earth's seasons?
- correct answer The Earth is tilted on its axis; when the northern hemisphere is tilted towards the Sun,
it warms and we're in summer. When it's tilted away, that's winter.
When warm air rises and cools, what happens?
- correct answer The air expands and cools, and water condenses into droplets and falls. Rain!
Why does it rain so much in the Olympic Peninsula? (This is a peninsula west of Seattle, home of the
Olympic mountains.)
- correct answer Warm, wet air from the Pacific is pushed up as it passes over the mountains. The air
expands and cools, and the moisture falls as rain.
Why is it so dry in Eastern Washington, on the other side of the Cascade mountains from Seattle?
- correct answer Air coming from over the Pacific Ocean loses its water as it climbs up the Cascades,
casting a rain shadow on the east side of the mountains.
Almost every liquid gets less dense as it warms. Water gets MORE dense as it warms from 0C to 4C. Why
is this bizarre aspect of water so important?
- correct answer When the frozen (or nearly frozen) surface of a lake warms, the water sinks, which
pushes nutrient-rich water up from the depths.
Deep oceans do not have a high concentration of fish. Why might that be?
- correct answer Light does not penetrate down into the deep ocean, so there are very few primary
producers (plants), so there's little for fish to eat.
Why does the highly productive fishery off the coast of Peru occasionally have extremely bad years?
- correct answer In El Niño years, the trade winds—which drive an upwelling of nutrients—decrease.
answers 2026\2027 A+ Grade
What is the most important difference between species richness and species diversity?
- correct answer Species diversity takes species number AND relative frequency into account.
What is the key difference between primary productivity and net primary productivity?
- correct answer Net primary productivity represents just the energy used to build biomass.
"Diversity leads to stability." This slogan claims that ecosystems with a large number of species present
are more stable than ecosystems with a low number of species. Which of the following lines of evidence
support this claim?
- correct answer As the number of plant species increases, resistance and resilience increases
What is biomass?
- correct answer total organic matter, usually measured per plant or per square meter
Why would a sampling effect lead to higher productivity in an experimental plot?
- correct answer If a few highly productive species are present in a community, biomass production will
be a function of whether or not they are present.
What is a functional group?
- correct answer Species that use resources or allocate resources in a similar way
In biological communities, what is "resistance?"
- correct answer degree of change during and after a disturbance
In biological communities, what is "resilience?"
- correct answer ability to "bounce back" after a disturbance, to the pre-disturbance conditiion
, What is a "natural experiment?"
- correct answer an unplanned/unmanipulated change in environmental conditions that can be
exploited to answer a question
What is the difference between climate and weather?
- correct answer Climate consists of long-term conditions; weather consists of short-term conditions.
What causes the Earth's seasons?
- correct answer The Earth is tilted on its axis; when the northern hemisphere is tilted towards the Sun,
it warms and we're in summer. When it's tilted away, that's winter.
When warm air rises and cools, what happens?
- correct answer The air expands and cools, and water condenses into droplets and falls. Rain!
Why does it rain so much in the Olympic Peninsula? (This is a peninsula west of Seattle, home of the
Olympic mountains.)
- correct answer Warm, wet air from the Pacific is pushed up as it passes over the mountains. The air
expands and cools, and the moisture falls as rain.
Why is it so dry in Eastern Washington, on the other side of the Cascade mountains from Seattle?
- correct answer Air coming from over the Pacific Ocean loses its water as it climbs up the Cascades,
casting a rain shadow on the east side of the mountains.
Almost every liquid gets less dense as it warms. Water gets MORE dense as it warms from 0C to 4C. Why
is this bizarre aspect of water so important?
- correct answer When the frozen (or nearly frozen) surface of a lake warms, the water sinks, which
pushes nutrient-rich water up from the depths.
Deep oceans do not have a high concentration of fish. Why might that be?
- correct answer Light does not penetrate down into the deep ocean, so there are very few primary
producers (plants), so there's little for fish to eat.
Why does the highly productive fishery off the coast of Peru occasionally have extremely bad years?
- correct answer In El Niño years, the trade winds—which drive an upwelling of nutrients—decrease.
