Roles in Ecosystems

  • Every organism has its own spot in an ecosystem
  • The physical place an organism lives is called its HABITAT (think of it being like its "address")
  • Where an organism is in the food chain, where it breeds, the time of day it is active, and how it gets food, ALL make up an organisms NICHE (think of it being like its "job")

Species Interactions

  • There are SEVEN main types of species interactions that occur between organisms when they live in the same ecosystem:
      1. Neutralism - 2 organisms live in the same ecosystem, but have no interaction at all (ex: trees & dandelions; dolphins & seaweed)
      2. Predation - 1 organism (predator) kills and eats another organism (prey) (ex: cat & mouse; frog & insect; owl & squirrel; tiger & zebra)
      3. Competition - both organisms compete to get the same limited resource (ex: plants trying to get the same sunlight; frogs and salamanders trying to get the same insects)
      4. Parasitism - 1 organism (parasite) lives in or on another organism (host) harming it in a minor way (ex: fleas on a dog; ticks on a deer; tapeworms, lice and ringworms in humans)
      5. Mutualism - both organisms benefit (it is mutual!) (ex: humans and bacteria in intestines; insects pollinating flowers)
      6. Commensalism - 1 species benefits, other species is neither helped nor harmed (ex: remoras & sharks; birds & elephants)
      7. Inhibition - a defence mechanism that organisms have developed to protect themselves from other organisms (ex: toxins secreted by some frogs; spines on catci)
Video: PARASITISM, MUTUALISM, & COMMENSALISM









Survival Tactics

  • Competition can be tough for organisms, but many avoid it by operating in different niches
    • DID YOU KNOW? Hawks and owls eat many of the same species but hawks hunt during the day whereas owls hunt at night. Hawks also hunt in fields, while owls hunt mostly in the forest.
  • Mimicry is a clever way that organisms avoid becoming prey for hungry predators ... can you tell what the clever way is?
  • butterfly.jpg
    Monarch & viceroy butterflies

snakes.gif

sticks.jpg
A stick? Or a "stick-bug"?
fishes.jpg

GAME

Click here to play a game about prey and predators.

QUESTIONS

Research "mimicry". Make a short report (about 1/2 a page long) about WHAT it is, and more animals that exhibit this behaviour. Include pictures of more animals (other than the ones that Ms. Harris showed). Can you find any explanations as to HOW they do it?