A bee and a flower work together to benefit each other. This is an example of a ______. The bee helps the flower by pollinating it and the flower helps the bee by providing it with nectar.

How is commensalism different from mutualism?

Hermit Crabs live in shells made and then abandoned by snails.

Aphids are tiny insects that live on and eat the leaves of plants, removing vital nutrients from the plants.

Clown fish live among anemones, acting as a lure for the sea anemone's prey. The clown fish get protection and shelter from the anemone. This is an example of which type of symbiosis?

When Crocodiles have a tooth ache they open their mouth and let the Plover bird pick at the leftover meat stuck between the Crocodile's teeth.

Beechdrops (Epifagus virginiana) are leafless plants that lack chlorophyll. Beechdrops get their nourishment from the roots of beech trees, which reduces the amount of nutrients available to the trees themselves. This interaction is best described as —

Which of these best describes the relationship between epiphytes and trees?

A pearlfish spends the day inside the alimentary tract, or intestines, of a sea cucumber. The fish emerges from the sea cucumber at night to feed on small crustaceans. The pearlfish gets a safe place to live. The sea cucumber does not gain anything from the relationship, nor is it harmed.

A cymothoid isopod lives inside the mouth of a snapper fish. The isopod severs blood vessels in the fish’s tongue, causing the tongue to atrophy and degenerate. The isopod then hooks its pereopods, or legs, to the base of the fish’s tongue, essentially replacing the tongue. The isopod stays there for the rest of its life, feeding on blood, mucus, and stray pieces of food from the fish.

A boxer crab carries a pair of small anemones in its chelipeds, or claws. When approached by a predator, the crab waves the stinging tentacles of the anemones to deter the predator. The anemones benefit from the small particles of food dropped by the crab during feeding.

An alpheid shrimp digs and maintains a deep burrow. While underground, the shrimp is safe. Above ground, it is vulnerable to predators. A goby fish lives in the burrow with the shrimp. The goby fish sits at the entrance, keeping watch for predators, and signals the shrimp with a flick of its tail when it is safe to come out. Or, if a predator swims by, the goby darts into the burrow and the shrimp retreats further inside. These two animals are completely dependent on each other—the goby benefits by getting a burrow to live in and the shrimp knows when predators are near.

Corals feed off the byproducts of a microscopic algae living within their own tissue, called zooxanthellae. The photosynthetic activity of the algae is vital to the survival of the coral animals, which use the energy to extract calcium from the seawater and build their calcareous skeletons. The zooxanthellae are protected by the hard coral and obtain plant nutrients from the coral.

The siboglinid tube worm, found at deep-sea hydrothermal vents and cold seeps, has no digestive tract. It relies on symbiotic bacteria that live in the tube worm’s tissues. The bacteria oxidize hydrogen sulfide or methane for the worm.