Examination #2, Fall 1999
Section A--The Cast of Characters: For each of the items below, provide a definition and a specific example of an organism that functions in that role.
An organism that consumes living animal tissue, usually whole organisms rather than parts of an organism. Consumption of same usually results in death of prey item.
Lynx
An organism that consumes living plant tissue, usually only a portion of the total organism, eg., leaves, buds, twigs, etc. Does not result in the death of the organism since, organism being consumed is modular rather than unitary.
Antelope
An organism that reduces dead organic matter to its mineralogic state
Bacteria and Fungi
An organism that consumes dead material and the microbial fauna/flora associated with same
Amphipods in aquatic ecosystems
An organism that lives on the external surface of another organism and causes harm to that host through its actionson the surface of the host
Fish lice
Any organisms that lives in close physical contact with another organism, either externally or internally. Relationships may be + or - with respects to each other.
Lichen (algae and fungus) show a + + relationship. Trematodes and fish show a + - relationship
An insect that lays its eggs on another species so that when the egss hatch they are able to make use of that organism as a source of nutrients.
A number of species of wasps.
Section B--Glossary: Define each of the following terms:
When two individuals vie for the same resource (space, food, mates). It would be intraspecific if both are of the same species and interspecific if they belong to two different species.
A situation where a particular rate (often birth or death) is directly related to the population density of the species (numbers per area).
The production of a substance by a plant with the direct purpose of restricting other plants from cohabiting the same space occupied by the first.
The fundamental niches is the n-dimensional hypervolume that an organism could potentially inhabit. The realize niche is the actual hypervolme that the species occupys.
Facultative is a situation where a species can utilize a particular resource or situation when that resource or situation is present, but its existence is not totally depend upon that resource or situation.
A species that shows a wide rather than narrow range with respect to choices for food items, habitats, etc.
Section C--Concepts: Briefly discuss each of the following concepts
A concept normally applied to plant populations, but also true of some other modular organisms (bryozoa, hydrozoa) that essentailly states that as plant populations increase in numbers, there are internal feed back systems that regulate the number and sizes of individuals that occur in a stand.
A concept that states that a species population will spread itself over an environment by setting up defended areas occuppied by a single individual. This reduces episodes of direct conflict and also spreas resource utilization over a wider area.
When different species compete for the same resources, if their densities are high enough and the resources are limited in value, they must either partition out the resources, that is more finely divide up th eniche or one or more of the competing species must "move on" leaving the niche to one or the other of the competitors.
A situation where the control over the size of a species population is exerted not by the recipient of goods and services, but the by the supplier of goods and services (typically the biomass accumulated in a photosynthetic organism)
A concept associated with food getting where an organism that uses a particular resource makes a descision to switch from that resource to another resource because the costs associated with utilizing the first exceed the benefits.