Biogeography

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Chapter 8

• Biogeography

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Why Were Introductions of New Species into Europe
So Popular Long Ago?

• Biogeography
• The large scale geographic pattern in the
  distribution of species, and the causes and
  history of this distribution

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Wallaces Realms Biotic Provinces

• Realm
• Major biogeographic regions of Earth that are
  based upon fundamental features of the plants and
  animals found in those regions
• Taxa
• Categories that identify groups of living
  organisms based upon evolutionary relationships
  or similarity of characteristics (ex species,
  families, orders)
• Biotic Provinces
• A geographical region (realm) inhabited by a
  characteristic set of taxa, bounded by barriers
  that prevent the spread of those distinctive
  kinds of life to other regions.

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The main biogeographic realms for animals are
based on genetic factors .Within each realm, the
vertebrates are in general more closely related
to each other than to vertebrates in similar
niches in other realms.
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The major vegetation realms are also based on
genetic factors
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Biomes

• A biome is a kind of ecosystem. Similar
  environments provide similar opportunities for
  life and similar constraints.
• Rainforest
• Grasslands
• Desserts

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Precipitation and Latitudes relationship
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• Convergent Evolution
• The process by which species evolve in different
  places of times and, although they have different
  genetic heritages, develop similar external forms
  and structures as a result of adaptation to
  similar environments
• Ex) shapes of sharks

• Divergent Evolution
• Organisms with the same ancestral genetic
  heritage migrate to different habitats and evolve
  into species with different external forms and
  structures, but continue to use the same type of
  habitats
• Ex) Ostrichwings, but cant fly

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Relationship between climate and vegetation.
Boundaries are approximate.
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Geographic Patterns of Life within a Continent
Generalized cross section of N. America showing
weather, landforms and the geography of life.
Weather patterns move from W to E.
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Island Biogeography

• Theory of Island Biogeography
• Islands have fewer species than continents
• The farther away the island is from a continent,
  the fewer species it will have
• The smaller the island, the fewer the species
• Adaptive Radiation
• The process that occurs when a species enters a
  new habitat that has unoccupied niches and
  evolves into a group of new species, each adapted
  to one of these niches.
• Ecological Island
• An area that is biologically isolated so that a
  species occurring within the area rarely mixes
  with any other population of the same species
• Ex a pond in the woods, small stand of trees in
  a prairie,

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The farther away the island is from a continent,
the fewer species it will have is illustrated
here. Also depends on the size of the island, the
rate of immigration and the rate of extinction.
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Caribbean Islands
The larger the island, the greater the number of
species.
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Earths Biomes

• The Earth has 17 major biomes (different
  depending on source) , each with its own
  characteristic dominant shapes and forms of life.
• Most biomes have been heavily altered by human
  action.
• People have introduced exotic species to new
  habitats sometimes creating benefits, often
  creating problems
• Primary Rule Unless there is a clear and good
  reason to introduce an exotic species into a new
  habitat, dont do it.

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Global distribution of major land biomes.
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Mean sea-level air temperatures in celcius for
July.
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17 Major Biomes

• Tundras
• - treeless plains that occur in the harsh
  climates of low rainfall and low average
  temperature
• - two types artic tundra and alpine tundra
• - parts have permafrost permanently frozen
  ground
• 2. Taiga or Boreal Forests
• - includes the forests of the cold climates of
  high latitudes and high altitudes
• - dominant life forms including moose and other
  large mammals, small flowering plants and trees
• Temperate Dedicious Forests
• - occur in warmer climates that the boreal
  forest
• 4. Temperate Rainforest
• - moderate temperatures, over 250 cm/year of
  rain

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• 5. Temperate Woodlands
• - Slightly drier climate that the deciduous
  forests
• - fire is common and species adapt to it
• 6. Temperate Shrublands
• - also called chaparral miniature woodlands
• 7. Temperate Grasslands
• - include many North American parries
• 8. Tropical Rain Forests
• - high average temperature and rainfall
• 9. Tropical Seasonal Forest and Savannas
• - high average temperature, low latitudes,
  abundant but seasonal rainfall
• 10. Deserts
• - The driest region that vegetation can survive.

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11. Wetlands - Include freshwater swaps,
,marshes and bogs all have standing water 12.
Freshwaters - Have phytoplankton and
estuaries 13. Intertidal Areas - Areas exposed
to alternately to air during low tide and high
tide 14. Open Ocean - Also called the pelagic
region 15. Bethos - Bottom portion of the
ocean 16. Upwellings - Upward flows of ocean
water 17. Hydrothermal Vents - Occur in the
deep ocean were plate tectonic processes create
vents