3 Flashcards
Marginal habitats?
Habitats where a species may occur but won’t contain high density.
Is it possible for species to occupy unfavourable areas?
Species may occupy unfavourable areas since sink populations depend on immigration from source populations. Therefore, peripheral populations of a species range are often sink populations.
Populations can be a source when _____ and sink when______?
b > d, d > b
Can species be absent in favourable environments?
Yes due to geographic barriers or isolation (think hemlock trees) and changing populations (suitable niche space is changing often since some patches become occupied at irregular intervals).
Metapopulation?
Population consisting of a set of sub populations linked by a cycle of alternating colonization and extinction.
Metapopulation source/sink dynamics are ore likely to?
Occur toward the periphery of a species range.
Do populations vary overtime?
Yes
When conditions are favourable, populations can grow?
Exponentially but cannot continue indefinitely.
Population size is determined by a combination of?
Density dependent and density independent factors.
Population fluctuations?
Population increases and decreases (sometimes in erratic changes) from an overall mean.
Population cycles?
Populations show alternating periods of high and low abundance over constant time intervals.
When a population starts from a very small size, the initial phase grows similarly through which growth rate?
Exponential
Geometric growth?
Discrete time periods
Exponential growth?
Continuous reproduction
To have a growing population: lambda > or < 1?
Lambda > 1
