1.1 - INTRODUCTION TO ECOSYSTEMS Flashcards
What term best describes an organism’s habitat as well as the role it plays in its environment through its interactions with biotic and abiotic factors?
Niche
Which of the following is the BEST example of competitive exclusion?
a) A red, male C. cardinalis compete for the same resource as the tan, female C. cardinalis, causing the female to go extinct.
b) When one species of warbler evolves to consume resources that are different than a similar species of warbler within the same ecological niche.
c) A tan, female C. cardinalis outcompetes a red, male C. cardinalis for the same resource within the same niche.
d) P. aurelia and P. caudatum compete for the same resource and both populations decrease.
Choice D is correct.
Competitive exclusion is between two different species that are competing for the same resource. While one species will typically outcompete the other, both populations decrease. Sometimes the two populations can coexist but their populations are smaller than if they were not sharing the same niche.
The loss of coral species in some reef systems around the world is thought to be catastrophic PRIMARILY because
a) coral plants are the primary producers in the reef ecosystems, and their loss is attributed to the insulating effect of the oceans on the Earth.
b) most reef animals directly eat coral, and when they die there will be effects through all the trophic levels in a reef habitat.
c) corals are algae at the base of the food chain and provide important nursery areas for young fish and other sea animals.
d) the photosynthetic symbionts of coral produce energy to help sustain the coral animals and maintain the extensive physical habitat in the corals’ calcium-based skeletons.
Choice D is correct.
Coral is indeed an animal, of an ancient lineage in the phylum Cnidaria, that has important symbiotic relationships with tiny photosynthetic algae known as zooxanthellae. These tiny prehistoric plant-like cells produce sugars for the coral, and the coral gives them a home insider their own polyps.
The zooxanthellae transfer as much as 90% of the sugar and amino acid that they produce to the host coral body, providing for most of the coral’s energy and nutrients as the coastal waters are often nutrient-poor. The coral produces a calcium carbonate-based skeleton that in turn is a habitat for the incredibly diverse reef ecosystem that exists around it and is supported by it.
Loss of this reef ecosystem is indeed catastrophic not just because of the profound diversity it supports, but also to coastal civilizations that rely on the healthy reef ecosystem as a protein source and other economic endeavors such as ecotourism.
There are several types of parasitism.
Which of the following would NOT be classified as a parasitic relationship?
a) American mistletoe growing on a White Oak Tree.
b) A tick feeding off a White-Tailed Deer.
c) An epiphyte, such as Spanish Moss, growing on a Cypress tree.
d) A Brown-headed cowbird laying its eggs in an American robin’s nest.
Choice C is correct because it is NOT an example of parasitism. Epiphytes are plants that grow on the branches of larger plants but do no harm. Therefore, Choice C is an example of commensalism.
