Types of Interactions Section 3

Objectives  Distinguish between the two types of competition  Give examples of predators and prey  Distinguish between mutualism, commensalism and parasitism  Define coevolution and give an example

Interactions with the Environment  Limiting Factors: Populations cannot grow indefinitely because the environment contains only so much food. –Example: Food  Carrying Capacity: The largest population that a given environment can support over a long period of time –Example: Food

Interactions Among Organisms  Competition  Predators and Prey  Symbiosis  Coevolution

Competition  When two or more individuals or populations try to use the same limited resources (food, water, shelter, space, or sunlight).  Can occur among individual organisms or a population  Often during winter when resources are scarce

Predator and Prey  Predator: the organism that eats the prey  Predator adaptations: must be able to catch their prey –Run fast –Quick reflexes –Stalk

Predator and Prey  Prey: the organism that is eaten  Prey Adaptations: methods and abilities to keep from getting eaten –Poisonous –Run (fast) –Heightened senses (hear, see, smell) –Camouflage

Symbiosis  Symbiosis: a close, long-term association between two or more species –Mutualism –Commensalism –Parasitism

Mutualism  A symbiotic relationship in which both organisms benefit  Coral and Algae – Coral provides a home and Algae provides food

Commensalism  A symbiotic relationship in which one organism benefits and the other is unaffected  Sharks and remoras; remoras “hitch a ride” and feed on scraps while the shark is unaffected

Parasitism  A symbiotic association in which one organism benefits and the other is harmed  Parasite- organism that benefits  Host- organism that is harmed  Tomato Hornworm – see page 18

Coevolution  A long-term change that takes place in two species because of their close interactions with one another.  See page 18 for example and pictures

Inquiry Logs  How do organisms survive in different environments?  Today you learned….  This answers part of our unit questions by…  I know have questions about…