Unformatted text preview: 9/13/2011 Biodiversity 1 The Diversity of Life 2010: Year of Biodiversity
Threatened with extinction: 30% of amphibians 20% of mammals 12% of birds 27% of corals Video 1: In the Shadow of Siberian Tigers 1 9/13/2011 What is biodiversity? Where is diversity the greatest? Ancient and modern extinction rates BIODIVERSITY
Variety of life forms Most common measure: number of species At no time in the history of the earth have there ever been as many species on the planet as right now. How many species inhabit the earth? Described ~ 1.8 million Estimated ~ 3-100 million Conservative estimate ~ 6-10 million "An inordinate fondness of beetles"
Most described animals are insects ! Most insects are beetles. J.B.S. Haldane 2 9/13/2011 Most species have never been described by science Where do new species come from? Video 2: National Geographic
Smallest primate on earth (mouse lemur) Large, charismatic species are better studied Discovery rate of new species varies among groups
# species named Crustaceans Jan Brueghel (1613) Jan Brueghel (1613) 1750 Time (years) 1980 1750 Time (years) 1980 Known & Estimated Species Diversity by Group Taxonomic distribution of taxonomists
Land vertebrates Fish Plants Invertebrates Primack, 1996 # species named 3 9/13/2011 Marine Biodiversity
34 of 35 animal phyla occur in the ocean 16 of these are exclusively marine In this sense the oceans are more diverse than land Video 3: Associated Press Antarctic Discovery Most species nave never been described by science
Where do new species come from? 1) Deep sea and ocean bottoms 2) Tropical rainforests 3) Small, hard to see species (insects, microbes)
Remote places, things that are hard to see With very few exceptions, most taxonomic groups are most diverse in the tropics. 4 9/13/2011 A = 30,000 km 2 A = 30,000 km 2 Contained within are by far the most diverse ecosystems in North America A = 800,000 km 2 A = 800,000 km 2 Biodiversity here will just begin to rival that of South Florida 5 9/13/2011 A = 152,600 km2 Georgia South Florida Butterflies A = 152,600 km2 Georgia is 610 times larger than Florida Keys Florida Keys A = 250 km 2 Georgia 146 species (GA) 146 species (GA) Tropical Diversity 50 % of all species are tropical ! 138 species (Monroe Co., FL) 6 9/13/2011 Latitude and plant diversity Video 4: Discovery Tropical Diversity Tropical Diversity
Ancient and stable environment More diversity has accumulated there Lower extinction rates Dr. Terry Erwin Smithsonian Tropical Diversity Dr. Erwin could name only 1 out of every 40 species he found. Only 1 out of 40 species had ever been described. Tropical Diversity
50% of 2 million described species = 1 million tropical described species x's 40* = Leads to an estimate of ~ 40 million species in tropics.
* Remember only 1 in 40 are described. 7 9/13/2011 Larger islands support more species
2.5 Log(# of species) Hispaniola 2
Jamaica Cuba 1.5 Puerto Rico Montserrat 1 Saba Redonda 0.5 0 1 2 3 4 5 6 Log (Area in sq mi) Mammals on mountains Birds on woodlots Habitat Islands Mountain tops Fragmented woodlands Lakes Nature reserves
Arthropods on Spartina Mollusks in NY lakes Isolated habitats support fewer species
Number of species Distance from New Guinea 8 9/13/2011 Biodiversity is highest Near tropics On bigger habitat `islands' In less isolated habitats Biodiversity has increased over geologic time
Land Plant Diversity Insect Diversity Vertebrate Diversity Extinction happens ! General increasing trend over last 500 my General increasing trend over last 500 my Interrupted by 5 major mass extinctions 9 ...
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- Fall '08
- Biodiversity, marine biodiversity, Tropical Diversity