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Ecosystem Balance. E1 Relationships in the Ecosystem. Predators and Prey. All consumers must eat other organisms to get food Predators – consumers that actively hunt other living organisms Prey – the organisms a predator eats.
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Ecosystem Balance E1 Relationships in the Ecosystem
Predators and Prey All consumers must eat other organisms to get food • Predators – consumers that activelyhunt other living organisms • Prey – the organisms a predator eats • Predator and prey population sizes are closely linked • If a prey population grows, the predator population also grows shortly afterwards • If a prey population shrinks, the predator population also shrinks shortlyafterwards • There is always a delay in the predator/prey cycle
Symbiosis Some organisms donotkill the prey they feed on • Symbiosis – relationship in which two species live closely together • Parasites – Harmful symbiotic relationship • Parasitism – relationship in which one organism feeds on the tissues or body fluid of another • The organism the parasite feed on is called the host • Most parasites do not kill their host • Examples:fleas, ticks, lice, etc • Can occasionally be fatal
Parasitism A parasite lives on or in the body of the host • Herbivores do not kill the plants they eat, but they are not parasites • Parasite rely on the host for functions they cannotperform themselves • Example: Tapeworm • Cannot move by itself and has no sensory organs • Host moves and has the senses needed to survive • Density-Dependent limiting factor • Bigger and more crowded the host population, the moreparasites it can support and be transferred
Commensalism Commensalism – symbiotic relationship that benefitsone species but does notharm or help the other • Example: Barnacles and Whales • Barnacles live on the skin of whales • benefit from constant movement of food-carrying water past the swimming whale. • Whales are not harmed or helped
Mutualism Mutualism – symbiotic relationship that benefitsboth species • Often a result of coevolution • Example: Ants and Acacia tree • Example:Oxpecker and Rhinoceros or Zebra • Oxpeckereats the tick and parasites that live on the zebra’s skin • Helps the zebra by getting rid of parasites • Oxpecker flies away and screams a warning when there is danger • Warns the zebra of danger