Unwelcome Guests

Theme:Water Protection
Map #:5
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This activity helps students become aware of the impacts of invasive species in Ontario’s lakes and how invasive species are introduced into water systems. This fun activity focuses on one species, the Spiny Water Flea, and the interaction between a native and non-native species and the impact on habitat.

Key Messages

  • Water is home to more than just frogs. There are microscopic plants (phytoplankton) and animals (zooplankton) that depend on and contribute to maintaining a balanced ecosystem
  • Introduced plants and animals like the spiny Water Flea compete with native species for food and habitat
  • An aquatic ecosystem is made up of a variety of species that depend on one another for survival. Introduced species disrupt this balance and the whole ecosystem can be affected. The success of the Spiny Water Flea puts the native species at risk for survival

Ontario Curriculum Connections

Science and Technology
  • Understanding Life Systems, Grade 4 (Habitats and Communities)
    • analyze the positive and negative impacts of human interactions with natural habitats and communities, taking different perspectives into account, and evaluate ways of minimizing the negative impacts
    • identify reasons for the depletion or extinction of a plant or animal species (e.g. changes in or destruction of its habitat), evaluate the impacts on the rest of the natural community, and propose possible actions for preventing such depletions or extinctions from happening
    • identify factors that affect the ability of plants and animals to survive in a specific habitat
    • demonstrate an understanding of a community as a group of interactive species sharing a common habitat
    • explain why changes in the environment have a greater impact on specialize species than on generalized species
  • Understanding Life Systems, Grade 6 (Biodiversity)
    • demonstrate an understanding of biodiversity as the variety of life on earth, including variety within each species of plant and animal, among species of plants and animals in communities, and among communities and the physical landscapes that support them
    • describe ways in which biodiversity within species is important for maintaining the resilience of those species
    • describe ways in which biodiversity within and among communities is important for maintaining the resilience of these communties
    • explain how invasive species (e.g. zebra mussel, Asian longhorned beetle, purple loosestrife) reduce biodiversity in local environments


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