Ecosystems & Interactions
What is the difference between a biotic and an abiotic factor?
Biotic factors are living (like plants and animals); abiotic factors are nonliving (like sunlight, water, and soil).
Which process in the water cycle involves water vapor turning into liquid?
Condensation
What do producers use during photosynthesis to make food?
Sunlight, water, and carbon dioxide
What is a food web?
A system of interdependent food chains showing energy flow in an ecosystem.
What forms when different populations live and interact in an area?
A community
What is symbiosis?
A close and long-term interaction between two different species.
Name two abiotic factors found in freshwater ecosystems.
Examples: Temperature and dissolved oxygen.
Name one way the carbon cycle supports life on Earth.
Plants absorb CO₂ for photosynthesis, producing oxygen and glucose.
Why are producers considered the base of food webs?
They make their own food and provide energy for all other organisms.
What happens to the amount of energy as you go up a food chain?
It decreases, typically by 90% at each level.
What happens to the prey population if the predator population increases?
The prey population usually decreases.
Define mutualism and give one example.
Both organisms benefit. Example: bees and flowers.
What distinguishes a land ecosystem from a marine one?
Land ecosystems are on land and influenced by soil and air, while marine ecosystems are in saltwater and influenced by tides and salinity.
Explain how nitrogen becomes usable by plants.
Bacteria convert nitrogen gas into nitrates through nitrogen fixation.
What are the inputs and outputs of photosynthesis?
Inputs: carbon dioxide, water, sunlight; Outputs: glucose and oxygen
How is energy transfer modeled in an energy pyramid?
It shows decreasing energy from producers up to top predators.
How do behaviors like migration or hunting in packs help animals survive?
They improve access to resources and survival rates.
How is parasitism different from commensalism?
Parasitism harms one; commensalism benefits one without affecting the other.
What is a niche and how can physical traits help infer one?
A niche is the role an organism plays in its ecosystem; traits like sharp teeth or long legs can indicate diet or movement.
Use a model to describe how matter cycles between living and nonliving parts of an ecosystem.
Plants take CO₂ from air (nonliving) → animals eat plants (living) → animals die → decomposers return nutrients to soil (nonliving).
Conduct an investigation to determine how light affects photosynthesis.
Use aquatic plants in different light conditions and measure oxygen bubbles produced.
Classify these organisms as producer, 1st-, 2nd-, or 3rd-order consumer: grass, rabbit, fox, hawk.
Grass = producer, rabbit = 1st-order consumer, fox = 2nd-order, hawk = 3rd-order consumer.
Predict how lack of water could affect a population in an ecosystem.
It could cause death, migration, or decrease in population size.
Describe an example of two organisms cooperating for resources.
Ants farming aphids for honeydew or dolphins hunting in pods.
Compare the abiotic and biotic factors of land, marine, and freshwater ecosystems.
Land: Soil, temperature, trees, insects. Marine: Saltwater, fish, coral, pressure. Freshwater: Lakes, frogs, aquatic plants, low salinity.
Differentiate the main processes in the water, carbon, and nitrogen cycles.
Water: evaporation, condensation, precipitation; Carbon: photosynthesis, respiration, decomposition; Nitrogen: fixation, assimilation, denitrification.
How does photosynthesis contribute to the cycling of matter and flow of energy?
It converts solar energy into chemical energy and cycles carbon through ecosystems.
How does the size of a population relate to its position in a food web?
Higher-level consumers have smaller populations due to less available energy.
How do graphs help infer relationships between predator and prey populations?
They show patterns of rise and fall in populations over time and how they affect each other.
Describe an example of two organisms cooperating for resources.
It limits growth and may cause population decline if resources run out.