Animal Biogeography

Define Animal Biogeography

Study of distribution of animals in space

What are the two main types of Animal Biogeography?

Historical and ecological

History of Historical Biogeography. Who was involved?

Biogeographic patters gave rise to some of the eary anomalies leading people to think about evolution. Buffon, Darwin, and Alfred R. Wallace

Buffon

late 1700’s. Large cats in New and Old World

Darwin

1830’s. Galapagos animals.A

Alfred R. Wallace

Broad zoographic regions based largely on mammals and birds.

• “Wallace’s Line” in Indonesia separates Oriendtal from Australian fauna

What does historical biogeography today look to?

evolutionary history and geology to explain species distribution

What is a vicariant event?

When ancestral populations are divided by a geographical barrier (mountains, river, sea, etc.), can split and diverge into 2 or more species.

Vicariance biogeography

combines phylogenetics based on past speciation with geographical distribution to produce area cladograms

If common geological events gave rise to splitting, we expect multiple groups to show _____________________.

The same patterns

Pangaea and Gondwanaland had continental Drift due to ……

plate tectonics explains otherwise puzzling distribution patterns

Pangaea

All continents united (210) mya, Upper Triassic)

Gondwana

Aouthern continents still united (180 mya, Jurassic). Gondwanan distributions are common

Dispersal

Animals can also move from one area to another

Examples of Dispersal

• islands

– oceanic vs. continental

– species/area curves

– balance between immigration and extinction

Great American Interchange

– ~3.5 mya Panamanian land bridge arose, allowing animals from N. America to go to S. America (& vice versa)

– (as we have seen, also a vicariant event for marine critters)

Climate Cycles & Vicariance

• During Ice Ages (3 mya up until 10,000 years ago), animal & plant distributions very different (e.g., La Brea Tar Pits)

• As climate warmed, many species retreated up mountains, became isolated

Are environmental conditions important in determining animal distributions?

Yes

What are the different kinds of environments?

How can environments be classified?

into broad biomes – typical plant & animal communities

What are the 10 major biomes?

• Tropical Forest

• Temperate Forest

• Desert

• Tundra

• Taiga (boreal forest)

• Grassland

• Savanna/tropical grassland

• Freshwater

• Marine

• Ice

Who first pointed out biomes?

Alexander von Humboldt

How do we classify marine zones?

• Benthic

  • Intertidal

  • Subtidal

• Pelagic

  • epipelagic

  • mesopelagic

  • bathypelagic

  • abyssopelagic

Most animals are ____, relatively few are _____. ______ and _________ _____ are richest in animal life. (marine zones)

benthic, pelagic, intertidal, nearshore subtidal

Intertidal Zonation

Rocky shores stratified based on tidal exposure:

• spray zone

• high tide zone

• middle tide zone

• subtidal

Integration of Historical & Ecological Biography

e.g., Anolis lizards in Caribbean

• similar ecomorphs have repeatedly evolved on different islands

phylogeny reconstruction leads to understanding of _______ and ______ history of these forms

phylogenetic, ecological