Ch 11 Species Section 01 Section 02

A. SPECIES EXTINCTION The three levels of extinction are: Locally: A species is no longer found in an area it once inhabited but is still found elsewhere in the world. Ecologically: Occurs when so few members of a species are left they no longer play its ecological role. Globally (biologically): Species is no longer found on the earth.

Endangered and Threatened Species: Ecological Smoke Alarms Endangered species: so few individual survivors that it could soon become extinct. Threatened species: still abundant in its natural range but is likely to become endangered in the near future. Show some information about bluefin tuna and it’s status Figure 11-3

Swallowtail butterfly Humpback chub Golden lion tamarin Siberian tiger Grizzly bear Kirkland’s warbler Knowlton cactus Florida manatee African elephant Figure 11.3 Endangered natural capital: species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and 1,260 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger. Utah prairie dog Swallowtail butterfly Humpback chub Golden lion tamarin Siberian tiger Fig. 11-3, p. 224

Giant panda Black-footed ferret Whooping crane Northern spotted owl Blue whale Figure 11.3 Endangered natural capital: species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and 1,260 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger. Mountain gorilla Florida panther California condor Hawksbill sea turtle Black rhinoceros Fig. 11-3, p. 224

California Condor SHOW VIDEO

Biologists use measurements and models to estimate extinction rates The first species to go tend to be the big, the slow and the tasty ones—ones whose valuable parts can be sold Tigers bones Rhino horns Biologists use measurements and models to estimate extinction rates Background extinction, mass extinctions, and mass depletions account for a loss of 99.9% of all species that have ever existed Show video on player for illegal wildlife trade and depletion happening in the galapagos islands

Silurian Permian Jurassic Cambrian Ordovician Devonian Devonian Terrestrial organisms Silurian Permian Jurassic Cambrian Ordovician Devonian Devonian Cretaceous Pre-cambrian Carboniferous Marine organisms Number of families Tertiary Quaternary Figure 4.13 Natural capital: changes in the earth’s biodiversity over geological time. The biological diversity of life on land and in the oceans has increased dramatically over the last 3.5 billion years, especially during the past 250 million years. During the last 1.8 million years this increase has leveled off. Millions of years ago Fig. 4-13, p. 94

Predicting extinctions is always difficult because of three factors. Extinction usually takes a long time and is difficult to document/prove. A small percentage of the world’s species have even been identified. We know very little about most of the world’s identified species

SPECIES EXTINCTION Some species have characteristics that make them vulnerable to ecological and biological extinction. Figure 11-4

RED LIST SHOW WEBLINK

Various methods are used to estimate extinction rates The World Conservation Union as kept Red Lists that are the world standard for listing all threatened species throughout the world. “Half of mammals 'in decline', says extinction Red List” Oct 6, 2008 Nearly 40 percent of 44,838 species catalogued are listed as "threatened" with extinction, with 3,000 of them classified as "critically endangered," Species-area relationship is defined by the number of species’ increasing as the size of an area increases Show red list link

When an area decreases by 90%, about 50% of the species there become extinct Use models to estimate a species extinction risk by predicting population size, habitat changes/availability, and species interaction Estimates of future extinction vary due to different assumptions

SPECIES EXTINCTION Show them link for fish to avoid. Percentage of various species types threatened with premature extinction from human activities. Figure 11-5

SPECIES EXTINCTION Scientists use models to estimate the risk of particular species becoming extinct or endangered. Figure 11-6

Using estimated extinction rates, 20% of the world’s present plant and animal species will be gone by 2030; 50% would vanish by 2099. Greater extinction rates than predicted are likely because of several factors Species loss and biodiversity loss will likely increase because of exponential population growth Biologically diverse areas (hot spots) rate of extinction may be as high as 25-50%

Possible colonization sites for new species are being eliminated, degraded and simplified by human activities so that new species cannot arise Such a crisis may contribute to dominance of the world by species with survival power—cockroaches, rats and weeds!!

IMPORTANCE OF WILD SPECIES We should not cause the premature extinction of species because of the economic and ecological services they provide. It will take 5 million years for speciation to rebuild the animals and plants we will destroy in 100 years. Medicinal properties are found in many plants and some animals A male lion skin is worth $1,000; a male lion living for 7 years produces $515,000 Bats, often targeted for destruction by man, feed on crop-damaging insects, and pollinate flowers

Some believe that each wild species has an inherent right to exist. Some people distinguish between the survival rights among various types of species (plants vs. animals).