A fallen, decaying log on the forest floor is classified as this type of factor, even though it’s dead.
Biotic
In this relationship, the "host" is the organism that loses out.
Parasitism
This interaction intensifies specifically when the population density increases and resources become scarce.
Competition
You cannot have a Community without multiple different ones of these.
Populations
Two male deer fighting over a mate is this specific type of interaction.
Competition
While water is abiotic, a drop of pond water viewed under a microscope is often considered this because of what’s swimming in it.
An ecosystem
A bird building a nest in a tree gets a home; the tree is unaffected. This specific relationship is...
Commensalism
If the prey population crashes, this population will likely crash shortly after.
The Predator population
This is the highest level of organization that includes non-living factors.
Ecosystem
Tapeworms living inside a human intestine eating the human's food.
Parasitism
Dissolved oxygen in a lake is essential for fish, but the oxygen itself is this type of factor.
Abiotic
Nitrogen-fixing bacteria living in plant roots help the plant grow, and the bacteria get sugar. Both win.
Mutualism
Invasive species are dangerous because they often have no natural predators, leading to excessive _______ with native species for food.
Competition
A mule (the baby of a horse and donkey) is alive, but it cannot reproduce. Therefore, horses and donkeys are not the same _______.
Species
An aquarium tank with water, gravel, plants, fish, and a light filter represents this level of organization.
Ecosystem
A seashell found on the beach, with no animal inside it, is this factor.
Biotic
This term describes the relationship between a hawk and a mouse, but not a flea and a dog.
Predation
Counting all the Maple trees in a specific forest gives you this specific level of organization.
Population
Yeast acts as a decomposer and is a living thing, but you usually need a microscope to see it, making it a...
Microorganism
All the bacteria, fungi, and tiny insects living in a single square foot of soil (excluding the soil itself).
Community
In a soil sample, the clay and sand are abiotic, and the decomposing humus is biotic, making it a what?
Mechanical Mixture
If you remove a parasite from its host, the host usually improves. If you separate organisms in this relationship, both usually suffer.
Mutualism
A sudden drop in the abiotic water supply will immediately decrease the size of the _______.
This organism captures energy to survive but is also the specific target of predation.
Prey