Relationships in the Food Web Symbiotic relationships living

Relationships in the Food Web • Symbiotic relationships: “living together” • Predation (+/-) – Species hunt other species • Parasitism (+/-) – one species benefits, one is harmed • Competition (+/-) – Species “fight”/ “use” the same resources • Commensalism (+/o) – one species benefit, one is unbothered • Mutualism (+/+) – Both species benefit

Predation

Living Relationships • Predator-Prey Relationship – beneficial for one species and harmful to another, involves a fight for survival. • However, some species enhance their chances of survival by forming close, permanent relationships with other species symbiosis.

Symbiotic Relationships cont. • Parasitism – relationship in which one organism derives benefit at the expense of the other. • Ticks are parasites of animals like dogs, obtaining nutrients from the blood of their host. • Parasites harm, but usually do not kill, the host.

Parasitism

Competition This happens when 2 or more individuals strive to obtain the same resources when these are in short supply. The more similar the individuals are, the more intense the competition.

Competition

Commensalism

Symbiotic Relationships • Commensalism – relationship in which one species benefits and the other species is neither harmed nor benefited • The clownfish lives among the stinging tentacles of an anemone and is protected from potential predators not immune to the sting of the anemone.

Mutualism

Symbiotic Relationships cont. • Mutualism – relationship in which both species benefit • Some fish and shrimp clean the bodies and mouths of large fish and turtles. • The cleaner fish get a meal while the large fish have parasites removed.

Community Interactions • Predation-

Community Interactions • Symbiosis- relationship where organisms live together

Community Interactions • Mutualism

Community Interactions • Mutualism

Community Interactions • Commensalism

Community Interactions • Parasitism

Ecological Succession – Ecosystems are constantly changing in response to natural and human disturbances. – older inhabitants die out – new organisms move in – series of predictable changes that occurs in a community over time

Primary Succession • In this example, a volcanic eruption has destroyed the previous ecosystem.

• The first organisms to appear are lichens.

• Mosses soon appear, and grasses take root in the thin layer of soil.

• Eventually, tree seedlings and shrubs sprout among the plant community.

Ecological Succession • Components of an ecosystem can be changed by natural events, such as fires. • When the disturbance is over, community interactions tend to restore the ecosystem to its original condition through secondary succession.

Marine Ecosystem Succession • Succession begins when a whale dies and sinks to the ocean floor.

• Within a year, most of the whale’s tissues have been eaten by scavengers and decomposers.