Tertiary

1. Species and families experiencing mass extinction Bar width represents relative number of living species Millions of years ago Era Period Extinction Current extinction crisis caused by human activities. Many species are expected to become extinct within the next 50–100 years. Quaternary Today Cenozoic Tertiary Extinction 65 Cretaceous: up to 80% of ruling reptiles (dinosaurs); many marine species including many foraminiferans and mollusks. Cretaceous Mesozoic Jurassic Extinction Triassic: 35% of animal families, including many reptiles and marine mollusks. 180 Triassic Extinction Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites. 250 Permian Carboniferous Extinction 345 Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites. Devonian Paleozoic Silurian Ordovician Extinction 500 Ordovician: 50% of animal families, including many trilobites. Cambrian

2. Effects of Humans on Biodiversity • The scientific consensus is that human activities are decreasing the earth’s biodiversity.

3. SPECIES EXTINCTION • Species can become extinct: • 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. Some animals have become prematurely extinct because of human activities.

4. Endangered and Threatened Species: Ecological Smoke Alarms • Endangered species: so few individual survivors that it could soon become extinct. • Rare species: so few individual survivors that it could soon become extinct. • Threatened (Vulnerable) species: still abundant in its natural range but is likely to become endangered in the near future.

6. K-selected species • Some species have characteristics that make them vulnerable to ecological and biological extinction. • https://youtu.be/VEMtc1w4z6c Figure 9-4

7. SPECIES EXTINCTION • Scientists use measurements and models to estimate extinction rates. • The International Union for the Conservation of Nature and Natural Resources (IUCN) publishes an annual Red List, listing the world’s threatened species. • The Red List contains 25, 821 species at risk for extinction. Up from 16,306 from 2015.

8. SPECIES EXTINCTION

9. Causes of Endangerment • Conservation biologists summarize the most important causes of premature extinction as “HIPPCO”: • Habitat destruction, degradation, and fragmentation • Invasive species • Population growth • Pollution – air, water, soil, etc • Climate Change • Overharvest – over-hunting, commercial harvest (sold for profit) • Habitat Loss- people moving in (the number one reason for endangerment!)

10. Indian Tiger Black Rhino Range 100 years ago Range in 1700 Range today (about 2,300 left) Range today (about 3,600 left) Asian or Indian Elephant African Elephant Former Range Probable range 1600 Range today (34,000-54,000 left) Range today

11. Habitat Loss • Habitat loss—due to destruction, fragmentation or degradation of habitat—is the primary threat to the survival of wildlife. • May be natural or unnatural, and may be caused by habitat fragmentation, geological processes, climate change, or human activities such as the introduction of invasive species or ecosystem nutrient depletion. • The current rate of deforestation is 160,000 square kilometers per year, which equates to a loss of approximately 1% of original forest habitat each year. Other forest ecosystems have suffered as much or more destruction as tropical rainforests.

12. Natural Capital Forests Ecological Services Economic Services Support energy flow and chemical cycling Reduce soil erosion Absorb and release water Purify water and air Influence local and regional climate Store atmospheric carbon Provide numerous wildlife habitats Fuelwood Lumber Pulp to make paper Mining Livestock grazing Recreation Jobs Fig. 10-4, p. 220

13. Harvesting Trees • Building roads into previously inaccessible forests paves the way for fragmentation, destruction, and degradation. Figure 10-5

14. Harvesting Trees • Trees can be harvested individually from diverse forests (selective cutting), an entire forest can be cut down (clear cutting), or portions of the forest is harvested (e.g. strip cutting). Figure 10-6

15. Harvesting Trees Effects of clear-cutting in the state of Washington, U.S. Figures 10-18 and 10-8