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Practice Echinoderms
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Invasion Down Under
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When Sea Stars Attack


Invasive Species

Why It Matters

Sea Star War

An invasive species is a non-native species which enters a new ecosystem. Often these individual invaders just die because they cannot deal with an ecosystem they did not evolve in or there are too few invading individuals to make a viable population. Essentially, unless an individual can reproduce asexually or is a pregnant female, you need at least one female and one male to grow a population. 100 males may cause problems but unless the species can change sex (which some species can and it is called sequential hermaphroditism; you can find out more here: http://www.reefscapes.net/articles/articles/2002/hermaphroditism.html). There are never going to more than 100 individuals. But sometimes the invaders hit the jackpot and enter an ecosystem where they have no predators and then there can be problems. Watch this video to see what is happening in the "Land Down Under."

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Use the below resources to answer the following questions

  1. How can biofouling spread invasive species in aquatic environments? Can you think of any way to prevent the spread of invasive species by this means?
  2. How can a ship’s ballast water spread invasive species? Can you think of any way to prevent the spread of invasive species by this means?
  3. How does it appear Asterias amurensis made it to Australia?
  4. What affect if any has Asterias amurensis had on commercial fisheries in Australia?

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