Niche: An individual’s ecological role

Interactions among species are the threads in the fabric of communities, holding them together and determining their nature

Ecologists have organized species interactions into several fundamental categories

Competition = relationship where multiple organisms seek the same limited resources:
Food, Water, Space, Shelter, Mates, Sunlight

Amensalism = variation of a competitive relationship, in which one organism is harmed and the other is apparently unaffected
Difficult to pin down

Intraspecific competition = among members of the same species
High population density = increased competition
Interspecific competition = among members of two or more species
Can lead to either competitive exclusion or to species coexistence