Cal Poly NR 305 Midterm Exam Questions
with Verified Correct Answers
What are the four core characteristics of an ecosystem? Explain each.
Web of interactions
More than the sum of its parts
Stability (among essential processes)
Diffused boundaries
What is ecology, and how do humans study ecology?
How nature works, including human impacts. The relationship between organisms and the
environment. There are many subsets we study. We observe, experiment, and research.
Explain the different levels of diversity and complexity exist in ecology (hint: think
about genetics, populations, communities, ecosystems, etc).
Genomic, Population (species), Community, Ecosystems (abiotic and biotic), Biomes
What is feedback? Explain the difference between positive feedback and negative
feedback and give an example of each.
When a process is modified by its output/effect.
Positive: Melt ice, lowers albedo, melts more ice...
Negative: More wolfs = less deer, less deer = less wolves, less wolves = more deer...
Explain the Gaia hypothesis. [grading note: 3 parts - what it says about organisms'
actions, what those actions ensure, and what it indicates about evolution]
The Gaia hypothesis suggests the earth is a like a single organism. (1) Organisms actively
regulate the earth's conditions, like how the body maintains homeostasis. (2) Collectively,
, organisms ensure the mechanism of the earth functions. (3) Species coevolve with the ever-
changing environment, forming a persistent relationship.
Briefly explain the natural and artificial methods by which atmospheric nitrogen is
converted to ammonia and nitrates. [3 parts]
Microbial Nitrogen Fixation
Haber-Bosch Process: N + H = Ammonia
Lightning: High energy breaks triple bonds.
In your own words, what are three ways that land plants influence the water cycle?
1. Diversify Soil Structure; porosity, permeability.
2. Transpiration; water loss to atmosphere through leaves.
3. Surface area for water to condense.
What are the components of a fire regime? Give an example of how a fire regime may
change. [name 4 components, and an example]
Pattern (ground, surface, understory, crown)
Timing (season, return interval)
Severity (mortality, regeneration time, nutrient loss)
Intensity (energy released)
Ex. Pine Beetle, Droughts
Describe the different ways fuels may be categorized in a forest. [4 parts]
Location: (ground, surface, understory, crown)
Continuity: (vertical, horizontal, not)
Age, Moisture
with Verified Correct Answers
What are the four core characteristics of an ecosystem? Explain each.
Web of interactions
More than the sum of its parts
Stability (among essential processes)
Diffused boundaries
What is ecology, and how do humans study ecology?
How nature works, including human impacts. The relationship between organisms and the
environment. There are many subsets we study. We observe, experiment, and research.
Explain the different levels of diversity and complexity exist in ecology (hint: think
about genetics, populations, communities, ecosystems, etc).
Genomic, Population (species), Community, Ecosystems (abiotic and biotic), Biomes
What is feedback? Explain the difference between positive feedback and negative
feedback and give an example of each.
When a process is modified by its output/effect.
Positive: Melt ice, lowers albedo, melts more ice...
Negative: More wolfs = less deer, less deer = less wolves, less wolves = more deer...
Explain the Gaia hypothesis. [grading note: 3 parts - what it says about organisms'
actions, what those actions ensure, and what it indicates about evolution]
The Gaia hypothesis suggests the earth is a like a single organism. (1) Organisms actively
regulate the earth's conditions, like how the body maintains homeostasis. (2) Collectively,
, organisms ensure the mechanism of the earth functions. (3) Species coevolve with the ever-
changing environment, forming a persistent relationship.
Briefly explain the natural and artificial methods by which atmospheric nitrogen is
converted to ammonia and nitrates. [3 parts]
Microbial Nitrogen Fixation
Haber-Bosch Process: N + H = Ammonia
Lightning: High energy breaks triple bonds.
In your own words, what are three ways that land plants influence the water cycle?
1. Diversify Soil Structure; porosity, permeability.
2. Transpiration; water loss to atmosphere through leaves.
3. Surface area for water to condense.
What are the components of a fire regime? Give an example of how a fire regime may
change. [name 4 components, and an example]
Pattern (ground, surface, understory, crown)
Timing (season, return interval)
Severity (mortality, regeneration time, nutrient loss)
Intensity (energy released)
Ex. Pine Beetle, Droughts
Describe the different ways fuels may be categorized in a forest. [4 parts]
Location: (ground, surface, understory, crown)
Continuity: (vertical, horizontal, not)
Age, Moisture
