Classification
In the Arctic, which of these is biotic and which are abiotic: polar bears, snow, sunlight?
Polar bears are biotic; snow and sunlight are abiotic.
Which sequence correctly lists organization from largest (most inclusive) to smallest?
Ecosystem → communities → populations → organisms.
Is coral a biotic or abiotic factor in a reef experiment?
Biotic.
Two birds use the same material to build nests. What type of relationship does this describe?
Competition (for a shared resource).
Two birds eat berries from the same vine. Is this competition or not?
competition (they share the same food resource).
Which of these is a biotic factor: sunlight, snow, polar bears?
Polar bears.
Define a population in one sentence.
A population is a group of organisms of the same species living in the same area.
200 — Q: Are tiles used in a coral growth experiment biotic or abiotic?
Abiotic.
Jackals follow tigers and eat leftover food. What type of relationship is this?
Commensalism (jackals benefit, tigers are neither helped nor harmed).
Which describes competition: two male deer fight over a mate, or a hyena scavenges leftovers from a lion?
Two male deer fighting over a mate is competition.
Give two examples of biotic factors and two examples of abiotic factors from a forest ecosystem.
Biotic: trees, deer (or fungi, insects). Abiotic: soil, sunlight (or water, temperature).
What is the difference between a community and an ecosystem?
A community includes all interacting populations of organisms; an ecosystem includes the community plus the abiotic factors (nonliving things).
In an aquarium experiment, list three abiotic variables researchers should control.
Temperature, light (sunlight), water chemistry (salinity, pH).
A tick weakens a zebra by sucking blood. What relationship is this?
Parasitism (parasite benefits, host harmed).
Identify whether the following is competition, predation, mutualism, commensalism, or parasitism: Wolves hunt a deer in a pack to catch prey.
Predation(wolves are predators; deer is prey).
True or False — Dead leaves on the forest floor are considered a biotic factor.
True (they are once-living organic matter).
A pond contains frogs, algae, insects, and water. Identify the organisms that make up a community and what makes the pond an ecosystem.
Community = frogs, algae, insects (all populations of organisms). The pond is an ecosystem because it includes those organisms plus abiotic factors like water, sunlight, and temperature.
The coral-snail experiment showed different coral growth when snails were present. Identify which factors in the experiment are biotic and which are abiotic from this list: corals, snails, sand, sunlight, tiles.
Biotic: corals, snails. Abiotic: sand, sunlight, tiles.
Clownfish and anemones: clownfish get protection and clean parasites while anemones gain cleaning and sometimes nutrients. What relationship is this?
Mutualism (both benefit).
The paragraph: "There are many different types of competitive relationships including ____ relationships. Competition occurs within and between ____. Organisms compete for ____ resources. The role an organism plays in an area, also known as its ____, may lead to competition too." Fill blanks with the best choice from: predator-prey; populations; limited; niche.
predator-prey; populations; limited; niche. (This set best completes the paragraph.)
Explain why bacteria that decompose dead leaves are considered biotic but the nutrients released into the soil are abiotic.
Bacteria are living organisms (biotic) carrying out decomposition; the released minerals and inorganic compounds in soil are nonliving (abiotic) resources produced by that process.
Provide an example illustrating how changing one abiotic factor in an ecosystem can affect organisms at different organizational levels (organism, population, community).
Example: Decreasing water availability (abiotic) may cause individual plants to wilt (organism), reduce plant population size (population), and lower food availability for herbivores, altering predator-prey dynamics in the community.
Explain how an abiotic factor can indirectly change a biotic interaction (example from coral reef: temperature change → algae relationship).
Warmer temperatures can cause corals to expel beneficial algae (bleaching), weakening coral health and altering interactions with other organisms (e.g., making them more susceptible to disease or competition).
Give one real-world example of mutualism and explain how both species benefit (2–3 sentences).
Bees and flowering plants — bees get nectar/food while pollinating the flowers, which helps plants reproduce by spreading pollen.
Using the coral-snail experiment results, state and justify one conclusion about how biotic interactions (snails) affect coral populations and their access to abiotic space.
Conclusion: Snails reduce coral growth by eating or removing organisms that compete with corals for space or by directly damaging corals; thus biotic interactions can limit coral population size and reduce their ability to occupy available abiotic space (tiles/rock).