Value of genetic diversity Why are genes valuable
Value of genetic diversity • Why are genes valuable? Or • What kind of value do genes have?
Value of genetic diversity • Genes have instrumental value – they are valuable for what they do
Grassy Stunt Virus in Rice
Oryza nivara
Native habitat of O. nivara in Uttara Kannada, India and Distribution
Extinction
Current Extinctions
Rates of Extinction Expected from Fossil Record: • 4 species a year go extinct from 10 million living species • 1 mammal species (out of about 4000 living) extinct every 400 years • 1 bird species (out of just over 9000 living) extinct every 200 years • 40 plant species extinct in 400 years (out of 250, 000 living)
Rates of Extinction Rates of extinction on mainland areas since 1600 • mammals 1. 6% extinct (62 of 4000) • birds 1. 3% extinct (117 of 9000) • vascular plants 0. 3% extinct (596 of 250, 000)
Alwyn Gentry and friends in the field
Centinela Ridge, Ecuador ridge is located in box on map
Estimating Loss of Unknown Species • Based on the Theory of Island Biogeography from which we know that larger areas support more species and from which we know that if we reduce the size of an island, we lose species - this knowledge is described by the species-area equation • S = c. Az • where S = species number, A = area, c is a constant that varies depending on the type of species and habitat in question, z is the slope of the curve
Extinct Australian Megafauna
Some Extinct And still living Pleistocene Megafauna Species in top half came from South America to North America; species in bottom half from N. America to S. America
Extinct American mega-bird
Recent Pleistocene Extinctions
What is habitat fragmentation?
Habitat Fragmentation • Fragmentation is the breakdown of a habitat or ecosystem into smaller patches of that habitat or ecosystem that now are isolated from each other
Habitat Fragmentation
Island Biogeography
Charles Darwin and Alfred Russel Wallace
The Galapagos
Galapagos Tortoise
Galapagos Mockingbirds
Galapagos Mockingbirds collected by Darwin
Malay Archipelago
Beetles and Moths Collected by A. R. Wallace
Butterflies from Malay Archipelago
Sphingid Butterfly Diversity Malay Archipelago
Island Habitats in Baltic Sea
Reptile and Amphibian Species Area Curve for Caribbean Islands
Habitat Islands In the Great Basin Bird Species Mammal Species
Species Area Curve S= z c. A where: S = number of species A = area of island c = constant for habitat type - forest, desert, grassland, etc. z = slope of curve
Ant species On New Guinea and Nearby Islands
Real Slopes for Species-Area Curves Oceanic islands birds - New Guinea islands beetles - West Indies land plants - Channel Islands z=0. 22 z=0. 34 z=0. 37 Habitat islands birds - Andes paramo birds - mtns of Great Basin mammals - mtns of Great Basin inverts -caves in West Virginia z=0. 29 z=0. 165 z=0. 326 z=0. 72
Robert Mac. Arthur and E. O. Wilson originators of the Equilibrium Theory of Island Biogeography
Ruffed Grouse by Audubon
Ruffed Grouse – male mating display
Apostle Islands – Lake Superior
Mac. Arthur and Wilson concluded: 1. Small islands have fewer species because equilibrium species number is set at a lower level by the balance of immigration and extinction – this is a dynamic equilibrium 2. Small islands are more isolated so that after extinction, the rate of replenishment is lower for them
Krakatau – before and after 1883 eruption
Aerial photo of Anak Krakatau and Krakatau
Krakatau today
- Slides: 49