Taxonomic composition (structure) Trophic ecology (function) Ecological succession Microhabitats Ecological niches (OH) Populations Population structure: virtually all populations are discontinuous Encounter rates among individuals is variable Gene flow may be interrupted Population growth (can be negative) Causes Birth Death Immigration Emigration Exponential growth curve 
(virtually all populations are discontinuous Encounter rates among individuals; is; variable Gene flow)
virtually all populations are discontinuous Encounter rates among individuals
is
variable Gene flow