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Name: _____________________________________________ Ecosystem Balance Environmental Science E1 Relationships in the Ecosystem Predators and Prey All consumers must ___________ other organisms to get food • Predators – consumers that ___________________ _____________ other living organisms • Prey – the organisms a predator _____________ Predator and prey population ______________ are closely _________________ • If a _____________ population ________________, the _____________________ population also ______________ shortly afterwards • If a prey population shrinks, the predator population shrinks _____________________________ • There is always a ________________ in the predator/prey cycle Symbiosis Some organisms _____________________________ the prey they feed on Symbiosis – relationship in which two species ____________ closely ____________________ Symbiotic Relationships Parasites: ___________________ symbiotic relationship • Parasitism – relationship in which one organism _______________ on the tissues or body fluid of another • The organism the parasite feed on is called the ____________ • _____________ parasites do not kill their host • Examples: ______________________________________________________________________ • Can occasionally be _________________ • A parasite lives ________ or _________ the body of the host • Herbivores do not kill the plants they eat, but they are ___________ parasites • Parasite rely on the host for functions they _______________ ___________________ themselves • Example: Tapeworm • Cannot _____________ by itself and has no ____________________ organs • ______________ moves and has the senses needed to survive • Density-Dependent limiting factor • ___________________ and more ____________________ the host population, the _________ _____________________ it can support and be transferred Commensalism: symbiotic relationship that _______________ ________ species but does _______ _____________ or help the other • Example: Barnacles and Whales • Barnacles live on the ___________ of whales • ____________________ from constant movement of food-carrying water past the swimming whale • Whales are _________ harmed or ____________________ Ecosystem Balance E1 Mutualism: symbiotic relationship that _________________ ____________ species • Often a result of ________________________ • Example: Ants and Acacia tree • Example: Oxpecker and Rhinoceros or Zebra • Oxpecker ___________ the tick and parasites that live on the zebra’s skin • Helps the zebra by getting ___________ of parasites • Oxpecker flies away and screams a ___________________ when there is danger • Warns the zebra of ______________________ Section Review 1. Which symbiotic relationship helps one species and does not harm or help the other? 2. Why are herbivores not considered to be parasites? 3. A relationship between species in which one species benefits and the other is harmed is called a. parasitism b. commensalism c. mutualism d. symbiosis 4. Though they are constantly changing, ecosystems are naturally a. recycled b. crowded c. balanced d. interacting 5. A predator is an animal that a. is a primary consumer b. is never eaten by other animals c. never eats vegetation d. actively hunts other animals 6. Lions hunt wildebeests. Therefore, wildebeests are a. predators b. prey c. hosts d. parasites 7. An increase in a predator population will directly result in a. ecosystem balance b. decreased predation c. starvation d. decline in prey population 8. The size of the host population controls a. the size of the prey population b. the size of the parasite population c. important bodily functions d. the geographic range of parasites 9. You would be most likely to find populations of host organisms parasitized when a. they have little to eat b. they are diseased c. they are overcrowded d. they cannot escape 10. Mutualism is often the result of a. cooperation b. fierce competition c. symbiosis d. coevolution c. coevolution d. predation 11. Parasitism is an example of a. symbiosis b. ecosystem balance 12. How will a decline in prey populations affect predator populations? a. b. c. d. Predators will increase due to the greater number of prey Predators will decrease due to lack of food Predators will move to a new ecosystem Predators will eat other predators