CK12 Life Science

Review Questions

1. Define competition.


2. If the geographic distributions of two similar species do not overlap, would you expect
   the two species to have character displacement? Why or why not?


3. Observations of natural populations and manipulative experiments show that two re-
   cently evolved species of threespine stickleback fish (Gasterosteusspp.) show two dis-
   tinct morphologies and feeding strategies in order to co-exist in the post-glacial lakes in
   which they live in western Canada. Morphologically they differ in the size, shape and
   the number and length of gill rakers, structures used in their feeding. Name two ways
   in which these fish species could use different feeding strategies in order to co-exist.


4. How might a predator lower a prey’s fitness?


5. In most types of grazing, does the predator lower a prey’s fitness? Why or why not?


6. A drone fly looks a lot like a bee, yet it is completely harmless as it cannot sting at all.
   What anti-predator mechanism is the drone fly using? Would you expect predators to
   always avoid drone flies?


7. In the mutualistic relationship between the Ocellaris clownfish and the Ritteri sea
   anemones, what benefit does the fish get?


8. Hosts may evolve defenses against their parasites. In turn, parasites evolve in response
   to these defense mechanisms, including evolving adaptations that are specific to a
   particular host taxon, even specializing to the point where they infect only a single
   species. How might such narrow host specificity be costly over evolutionary time?
   What would help to reduce this cost?

Further Reading / Supplemental Links

en.wikipedia.org/wiki/Symbiosis

• http://www.sciencenewsforkids.org/pages/search.asp


• http://www.blm.gov/education/LearningLandscapes/students.html


• http://www.nclark.net/CommunitiesBiomes


• http://www.ecokidsonline.com/pub/index.cfm

Vocabulary

camouflage When species have an appearance which helps them blend into the back-
ground.

character displacement Two or more species within the same area develop different spe-
cializations in order to coexist.