UNIVERSITY OF MICHIGAN
Exam 1 Key Terms Definitions &
Applications
Course: BIOL 173 BIOLOGY LAB
, KEY TERMS TO KNOW
a. Ecological diversity
The variation within an ecosystem, including the variety of life and habitats, and the
complexity of biological communities, relevant to a geographical location
b. Community composition
The specific makeup of different species within an ecosystem, including the identity
and relative abundance(s) of all species within the given ecological community
c. Species interactions
i. Competition (interspecific, intraspecific, interference, exploitative)
Competition is best described as the struggle for resources between
organisms in a given ecosystem (these resources are usually in limited
supply)
● Interspecific: Competition between members of different species
● Intraspecific: Competition between members of the same species
● Interference: Competition wherein one organism physically restricts
another organism's access to resources
● Exploitative: Competition when individuals interact indirectly as
they compete for common resources, like territory, prey or food
ii. Mutualism
Mutualism describes an ongoing interaction between two species whereby
both species benefit from the interaction. Examples include bacteria living
in root nodules, fungi growing on plants and coral polyps housing
photosynthetic algae
iii. Commensalism
Commensalism is a long-term biological interaction (symbiosis) in which
members of one species gain benefits while those of the other species neither
receive benefit or experience harm. Examples include a bird nesting in a tree