Interactions Among Living Things

Adaptations and Niches Every organism has a variety of adaptations that are suited to its specific living conditions and help it survive What is a niche? The job or role of an organism in the environment

Competition Struggle between organisms to survive as they attempt to use the same limited resources (Food, water, shelter, etc.)

Predation Interaction in which one organism kills another for food Predator-killer Prey-is killed May have a major effect on population size Many prey animals have adaptations that increase their survival.

Predator and Prey Adaptations

Symbiosis Any relationship in which 2 species live closely together and at least one of the species benefits. 3 TYPES: Mutualism, Commensalism, Parasitism

Mutualism Relationship in which both species benefit. The anemone receives protection from polyp-eating fish, like Butterfly Fish, which the Clown Fish chases away. The anemone also gets fertilizer from the feces of the Clown Fish. It is a near-perfect symbiosis.

Coral and Algae Mutualism At night, the coral polyp uses its stinging cells to catch and eat prey. But it needs food during the day so Zooxanthellae algae live in the coral, feasting on waste products. The algae photosynthesize during the day using sunlight to turn carbon dioxide into sugars. After taking what it needs, the algae produces a little extra sugar for the coral. Completing the cycle, carbon dioxide from the coral is used by the algae. The photo shows Zooxanthellae inside a coral polyp.

Commensalism One species benefits and the other is neither helped nor harmed. Here a titan triggerfish creates feeding opportunities for smaller fish by moving large rocks too big for them to shift themselves.

Commensalism A cattle egret follows large grazers such as cows, zebras and water buffalos to find its meals more quickly. When a grazer pulls up grass to eat, it also exposes organisms in the soil below. These are easy pickings for the egret and as the bird does not hinder the grazer, the relationship is a successful one.

Parasitism Relationship in which one species lives in, on, or inside another organism and harms it Fleas harm their hosts, such as dogs, by biting their skin, sucking their blood, and causing them to itch. The fleas, in turn, get food and a warm home.

Parasitism Some parasitic animals attack plants. Aphids are insects that eat the sap from the plants on which they live.

Parasitism Tapeworms are segmented flatworms that attach themselves to the insides of the intestines of animals such as cows, pigs, and humans. They get food by eating the host's partly digested food, depriving the host of nutrients.