Ecology and the environment


QUESTION 1: Mix and match (20 pts, 4 each)


Find the best connection for the statements below (a-e) with the statements 1-5 (also below). For your answers, write the corresponding number in the space between parentheses.


  1. Two species of warblers feed on insect larvae. The birds are active at different layers of the forest, and do not come into contact with one another. Nevertheless, the presence of one species limits the survival and reproduction of the other. (___)


  1. The Slaty flower-piercer, a common bird of the cloud forest of Costa Rica, feeds on flower nectar that it extracts by making a little hole at the base of the flower. In contrast with what hummingbirds do, this bird doesn’t provide a pollination service to the plants it feeds upon. (___)


  1. Populations of Burma Pythons and Yellow Anacondas are increasing drastically in the Everglades National Park. As a consequence, several bird and mammal populations are decreasing and turning into favorite prey times for these large reptiles. (___)


  1. Giant Kelp (a large algae) “forests” are unique marine ecosystems that occur in the Pacific coast of the USA. The health of these Giant Kelp forests is largely dependent on healthy populations of Sea Otters, which are the main consumers of sea urchins and other grazers that feed on the kelp. (___)


  1. When visiting and pollinating flowers a wasp species also obtains nectar as a food resource, and, as a result of this, its population grows 8% per month. However, sometimes there is a cost imposed by the flowers (i.e. wasp getting stuck in the flowers, time spent pollinating the flower instead of feeding on other species, etc.), which results in a 3% reduction in population growth per month. The flower also gains benefits from the pollination service and its population increases by 9% per month. But, this also means a cost for the flower (i.e. nectar production to feed the butterfly, flower damage by the pollinator, etc.) that reduces its population growth by 6% per month. (___)



  1. This is a clear example of the effect of a keystone species in the ecosystem.
  2. These species illustrate a case of exploitative interactions in a native habitat where they lack their own natural predators.
  3. Despite the unequal tradeoffs for both species, this is clear example of a mutualistic relationship between them.
  4. Two species illustrating a case of species indirect competition.
  5. This is a clear example of kleptoparasitism.


QUESTION 2: Fill in the blank with one or two words of your choice to complete these statements. You can use any words as long as they make an ecologically logical statement.  In addition, add a couple of sentences in which you demonstrate learning about the topic and/or how these concepts could be applied to explain ecological processes or species interactions. Sentences should add NEW information related to ecosystems, species or individuals or a specific example that makes an additional point. It is NOT about repeating the provided statement in your own words (25 points, 5 each)


For guidance, see this example:

In Equatorial regions, the sun’s rays strike Earth’s surface at a more ___PERPENDICULAR/DIRECT___ angle than they do toward the poles. This means that the same amount of energy is spread over a __SMALLER_ area in equatorial regions than in __POLAR_ regions.


Add your own supplementary statement:

Then you could add something like this: “For example, these differences in energy availability can cause latitudinal differences in vegetation patterns or plant diversity, as the tropics have higher annual rates of photosynthesis than polar regions”


  1. Many species of cleaner fish living on coral reefs clean other fish of _____________ that live on their fins. This relationship that involves the cleaner fish and its “clients” have been shown to be true ____________.

Add your own supplementary statement:

  1. A species of caterpillar has bright red and yellow coloration that indicates to the potential predators that they are unpleasant or even harmful to __________. This is an example of ______________ coloration.

Add your own supplementary statement:

  1. A fish community consists of 1,300 Bass, 400 Right-eyed Flounders, 2,300 Coho Salmon, and 200,000 Pacific Herring. The species richness of this community is______ and it shows that isn’t an _________ community.

Add your own supplementary statement:


  1. Moths resting on the trunks of trees often resemble the tree bark, such that potential __________ do not perceive them as prey. This is an example of ________________.

Add your own supplementary statement:




  1. Habitat loss is the greatest cause of biodiversity decline. For example, the ________native to North America’s Great Plains have been almost entirely converted to __________.

Add your own supplementary statement:



QUESTION 3:  Short answer (15 pts)

There are abiotic and biotic factors that keep population size of species under control. Provide two examples that affect  (or have affected) population size of native species in WA. You need to pick two real examples, provide specific species names and habitats/ecosystems where those species occur. You need to use different examples from the ones I used in lectures.


QUESTION 4: Short answers. For these questions you need to provide a clear explanation with  (20 pts, 10 pts. each.)


  1. Why is extinction important for ecosystems and ecological communities? But why do we talk about an unprecedented current rate of extinction in the history of life in our planet?


  1. What is the link between human population, ecosystem degradation and ecological footprint?




QUESTION 5: Short essay (min 180- max 400 words) (20 pts)


Write a short essay about the value of biodiversity. Make sure that in your essay you address why biodiversity is important for maintaining life in the planet and all it offers, but also how biodiversity contributes to human wellbeing and future development of human societies. In addition, provide 2 specific examples that illustrate the critical value that biodiversity has in your own life.





Extra-credit (4pts):


  1. Provide a short explanation for the interaction between two species of a biome different to what you covered in your presentation. Include species names and how each species impact on the fitness of the other one.


  1. Provide a specific example that illustrates one of the main threats to biodiversity in Washington State.