Lesson 3-How Do Organisms Interact?

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Lesson 3-How Do Organisms Interact?
Objectives

• Observe how organisms help each other
• Describe how organisms compete within an
  ecosystem
• Explain symbiotic relationships

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Vocabulary

• Competition
• Symbiosis
• Parasite
• Host

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Lesson 3

• Limiting Factors Competition for Resources
• In an ecosystem, organisms compete for space,
  light, food, water, air nutrients.
• Competition is the struggle among organisms for
  limited resources in an area.
• Every ecosystem and species must compete to stay
  alive
• A predator is an animal that feeds on other
  living animals
• Prey is an animal that gets eaten by the predator.

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Vocabulary

• 166-Competition
• The struggle among organisms for limited
  resources in an area.

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Write this Question in your books

• Q Why does an increase in the number of prey
  affect the number of predators?
• A The more prey there are, the more predators
  can be supported.

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Lesson 3

• B. Organisms Interact to Meet Their Needs
• Some organisms live together in a relationship
  called symbiosis.
• Symbiosis is a close relationship between
  organisms of different species in which one or
  both of them benefit. There are 3 types of
  Symbiosis (you will learn the 3rd one tomorrow!).
• Parasitism one species benefits while the other
  is harmed
• Parasite is an organism that lives in or on
  another organism
• Host is the organism that the parasite lives on
• Mutualism both organisms benefit

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Vocabulary

• 168 - Symbiosis
• A close relationship between organisms of
  different species in which one or both of the
  organisms benefit.
• 168 Parasite
• An organism that lives in or on another organism.
• 168 Host
• The organism that a parasite lives on.

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Write this Question in your books

• Q What effect does mutualisms have on organisms?
• A Both organisms benefit.

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Insta-Lab

• Model Behavior
• Think of a relationship between organisms that
  shows mutualism. Then make a model of this
  relationship with clay. How does this
  relationship benefit both organisms?

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Lesson 3

• C. Neither Help nor Harm
• The third type of Symbiosis Commensalism one
  organism benefits and the other organism is
  neither helped nor harmed.

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Write this Question in your books

• Q How are the effects of commensalism and
  parasitism different?
• A In commensalism, one organism benefits, and
  the other is neither helped nor harmed. In
  parasitism, one organism benefits, but the other
  is harmed.

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Lesson 3 Review

• In your groups, you will work on numbers
• 1, 3-6
• When you are finished, you may read, draw in one
  of the illustration books, work on other
  unfinished work or get on one of the computers if
  available.