Introduction to Biomes
Biogeography – the large-scale
geographic pattern in the distribution of
species, and the causes and history of
this distribution
The Rule of Climatic Similarity – similar
environments lead to the evolution of
organisms similar in form and function
and to similar ecosystems
This rule leads to the concept of the
biome
Biomes are the major regional groupings
of plants and animals discernible at a
global scale.
Their distribution patterns are strongly
correlated with regional climate patterns
and identified according to the climax
vegetation type.
However, a biome is composed not only
of the climax vegetation, but also of
associated successional communities,
persistent subclimax communities, fauna,
and soils.
The biome concept embraces the idea of
community, of interaction among
vegetation, animal populations, and soil.
A biome is also called a biotic area.
To understand the nature of the earth's
major biomes, one needs to learn for each:
1. The global distribution pattern:
Where each biome is found and how
each varies geographically.
A given biome may be composed of
different taxa on different continents.
Continent-specific associations of
species within a given biome are
known as formations and often are
known by different local names.
For example, the temperate grassland
biome is variously called prairie,
steppe, pampa, or veld, depending on
where it occurs (North America,
Eurasia, South America, and southern
Africa, respectively).
2. The general characteristics of the
regional climate and the limitations or
requirements imposed upon life by
specific temperature and/or
precipitation patterns.
3. There are other aspects of the
physical environment that can effect
plant growth more so then the climate
4. The soil order(s) that characterize
the biome and those processes
involved in soil development.
5. The dominant, characteristic, and
unique growth forms
(peculiar life histories or reproductive
strategies, dispersal mechanisms, root
structure)
6. The types of animals (especially
vertebrates) characteristic of the
biome and their typical morphological,
physiological, and/or behavioral
adaptations to the environment.
Exotic species – a species introduced
into a new geographic area
Endemic species – a species that is
native to a particular area and not
native elsewhere
Cosmopolitan species – a species with
a broad distribution, occurring all over
the world whenever the environment
is appropriate
Ubiquitous species – species that are
found almost anywhere
Convergent evolution – the process by
which species evolve in different
places or different times and develop
similar external forms and structures
as a result of adaptation to similar
environments
Divergent evolution – this is when a
population is separated, usually by
geographic barriers; the separated
subpopulations evolve separately but
retain some common characteristics