Population
What is population density?
Number of individuals per unit area
What is the primary source of energy for most ecosystems?
The Sun
What cycle involves water movement?
Water cycle
What is a niche?
An organism’s role in its environment
What is biodiversity?
Variety of life in an ecosystem
What is carrying capacity?
Maximum population size an environment can support
What process do producers use to make energy?
Photosynthesis
What process converts nitrogen gas into usable form?
Nitrogen fixation
What is competition?
Organisms competing for the same resource
What is a keystone species?
Species with a large impact on ecosystem
What type of growth curve is S-shaped?
Logistic growth
What trophic level are herbivores?
Primary consumers
What process returns CO₂ to the atmosphere?
Cellular respiration
What is mutualism?
Both species benefit
What is biomagnification?
Increase of toxins up the food chain
What limits population growth due to living factors?
Density-dependent factors
What happens to most energy between trophic levels?
It gets lost as heat (10% rule)
Where is most phosphorus stored?
Rocks and sediments
What is the competitive exclusion principle?
Two species cannot occupy the same niche
What causes climate change?
Increase in greenhouse gases
What is the difference between r-selected and K-selected species?
r: many offspring, little care; K: few offspring, high care
Why are food chains usually short?
Energy loss limits higher trophic levels
How do humans disrupt the nitrogen cycle?
Fertilizers causing eutrophication
What happens during ecological succession?
Gradual change in species over time
What is habitat fragmentation?
Breaking ecosystems into smaller pieces