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Chapter 8 Outline

Case Study: From Kelp Forest to Urchin Barren

Populations

CONCEPT 8.1 Populations are dynamic entities that vary in size over time and space.

Abundances change over time and space
Dispersal links populations
What are individuals?

Distribution and Abundance

CONCEPT 8.2 The distributions and abundances of organisms are limited by habitat suitability, historical factors, and dispersal.

Habitat suitability limits distribution and abundance
History and dispersal limit distribution and abundance

Geographic Range

CONCEPT 8.3 Many species have a patchy distribution of populations across their geographic range.

Geographic ranges vary in size among species
Populations have patchy distributions

Dispersion within Populations

CONCEPT 8.4 The dispersion of individuals within a population depends on the location of essential resources, dispersal, and behavioral interactions.

Resources and dispersal affect dispersion within populations
Individual behavior affects dispersion within populations

Estimating Abundances and Distributions

CONCEPT 8.5 Population abundances and distributions can be estimated with area-based counts, mark–recapture methods, and niche modeling.

Ecologists estimate abundance with area-based counts and mark–recapture methods
Ecologists used abundance data to track down a mysterious disease
Niche models can be used to predict where species can be found