Biogeography Unit III

Range

The geographic distribution of plants or animals where a particular species can regularly be found.

Distribution

The pattern of where a certain species is observed and the relative frequency.

Thematic Maps

Maps that represent the range of a species as a polygon, based on scientific understandings of movement patterns, climatic preferences, and other factors.

Contour Map

Illustrates characteristics of a population through the progressive drawing of lines, showing density changes over time.

Dot Map

A map based on actual observations and recorded encounters with a species, requiring extensive field work.

Population

The number of a given species in an area.

Source Populations

Environmental conditions favorable to producing an excess population of individuals that then disperse.

Sink Populations

Environmental conditions that allow for continued life, but without enough resources for excess populations.

Malthusian Theory

Represents the growth of population as connected to the available resources, indicating exponential growth until resource limits are reached.

Tolerance Range

The range of environmental conditions that organisms can survive in.

Niche

Combination of biotic and abiotic factors that allow a species to exist.

Fundamental Niche

The potential of a species to thrive without external factors influencing it.

Realized Niche

What a species can actually achieve given competition and other factors.

Hutchinson's Multidimensional Niche Concept

Conceptualization of species abundance based on environmental conditions.

Population Distributions

The pattern of where populations are located within an area, which can be clustered, uniform, or random.

Endemic Species

A species that exists in only one particular region.

Cosmopolitan Species

Species that are widely distributed across various geographic locations.

Provincialism

The existence of many endemic species in a distinct geographic area.

Disjunction

A species found in two disconnected geographical areas, but not found in the spaces between.

Wallace Line

A biogeographic boundary separating distinct regions of biodiversity in Asia and Australia.

Island Biogeography

The study of the ecological and evolutionary processes that shape the species diversity of islands.

MacArthur-Wilson Equilibrium Theory

Theory that describes the balance between immigration and extinction rates on islands.

Species-Energy Theory

The concept that areas with more available energy can support more species.

Vicariance

The geographical separation of a population through barriers, leading to speciation.

Dispersal

The movement of individuals or species from one location to another, they are moving themselves

Barriers

Natural or man-made obstacles that prevent species from spreading into new areas.

Speciation

The process of forming new and distinct species in the course of evolution.

Adaptations

Traits that enhance the survival and reproduction of organisms in specific environments.