Symbiotic Relationships Symbiosis is a close association between two or more organisms of different species. 3 types of associations: 1. Mutualism – both species benefit 2. Commensalism – one species benefits and the other is neither harmed or benefitted 3. Parasitism – one organism benefits at the expense of another (predator/prey relationships are parasitic)

Within any ecosystem, some organisms utilize resources and reduce the availability of those resources to other organisms.

The relationship between a predator and its prey. The relationship between a predator and its prey. Even predator and prey populations are related. If the predator population is low, the numbers of the prey species will increase. Most predator species will reproduce in larger numbers if food is abundant. As the numbers of the predator species increase, the prey population begins to decline.

Vermiliad and the Australian Acid Frog: A vermiliad is a type of plant found in rainforests. It lives and grows on trees found in this habitat. The Australian Acid Frog uses the vermiliad as shelter and often collects water from the leaves of the vermiliad. The Acid Frog does not eat or harm the vermiliad in any way.

Grizzly Bear and Salmon: During the summer months, salmon swim upstream to their spawning grounds where they reproduce. The grizzly bear often hunts in shallow water where the salmon must pass on their journey and can sometimes catch a salmon out of thin air using only its teeth.

Malaria Protozoa, Mosquitoes, and Humans: Malaria is transmitted to humans when an infected mosquito bites a person and injects the malaria into the blood. The malaria travels through the bloodstream and eventually infects the red blood cells. While in red blood cells, the malaria grows and develops until a mosquito takes a blood meal from an infected human and ingests human red blood cells containing the malaria. Then the malaria reaches the mosquito's stomach and eventually invades the mosquito’s salivary glands. When a mosquito bites a human, the process repeats.

Portuguese Man O’War and the Shepherd Fish: The Portuguese Man o' War is often found with a variety of marine fish, including the shepherd fish. The shepherd fish is able to avoid the stinging tentacles of the Man O’War and remain unharmed. The presence of the shepherd fish attracts other fish that the Portuguese Man o' War can feed on.

Humpback anglerfish and the Arrow Worm: The anglerfish lives in tropical to temperate parts of the ocean at depths of up 6,600 feet. They have a bait-like appendage, which resembles a fishing pole, attached to top of their spine which can be illuminated in order to attract other deep sea creatures. The Arrow Worm is one deep sea creature that is attracted to this deep water “light” and is often eaten by the Anglerfish if it ventures too closely.