Extinction. The real reason dinosaurs went extinct

Size: px

Start display at page:

Download "Extinction. The real reason dinosaurs went extinct"

Jared Nash
5 years ago
Views:

Extinction Extinction is a natural process Background

rate Mass extinction : widespread (global) extinction

went extinct 5 mass extinctions in the past (last one

Dying ): ~90% of marine species, 75% of land species

Now thought to be caused by Siberian volcanic eruptions

1 Extinction Extinction is a natural process Background or natural rate of extinction: loss of species at a low rate Mass extinction : widespread (global) extinction of large numbers of species The real reason dinosaurs went extinct 5 mass extinctions in the past (last one was 65 million years ago) Permian extinction ( Grand Dying ): ~90% of marine species, 75% of land species went extinct. Now thought to be caused by Siberian volcanic eruptions (enough lava to cover the US in 1,000 m of rock). CO2 vented at this time caused a catastrophic climate shift.

2 Are Humans Causing a Mass Extinction? Species are becoming extinct by over the rate before the Industrial Revolution Conservative estimates of extinction = % Growth of human population will increase this loss E.O. Wilson estimates that if extinction rate, of all species will be gone by 2100

3 Threatened & Endangered Species Endangered Species: Species that has so individuals that the species could soon become extinct over some or most of its natural range. Threatened Species: Species that is still relatively abundant, but because of is likely to become endangered in the near future. Worldwide about 25% of mammals are at risk of extinction. The highest percentages at risk are: apes & monkeys ( ) moles & shrews ( ) amphibians ( )

4 Percentage of Various Species Threatened with Premature Extinction IUCN = International Union for Conservation of Nature

5 Estimates from the IUCN (International Union for Conservation of Nature)

recycling, watershed value, production of oxygen, moderating climate, & detoxifying

v=8shr4zti5py Bioremediation: To solve (remedy) an environmental problem using a

6 Why Preserve Wild Species? economic & importance scientific & importance: ecological services include nutrient recycling, watershed value, production of oxygen, moderating climate, & detoxifying toxic substances Bioremediation: To solve (remedy) an environmental problem using a living thing. & recreational importance

7 Causes of Extinction & Depletion HIPPCO, fragmentation & degradation I (nonnative) species P and resource use growth P C O (poaching, overfishing etc.)

refuge must have adequate population size for genetic diversity Why is Genetic

8 1. Habitat Loss/Fragmentation Most Serious Threat to Biodiversity Habitat Fragmentation Reduces Genetic Diversity in a Population Area preserved for wildlife refuge must have adequate population size for genetic diversity Why is Genetic Diversity Important? Improves odds that members of population will be able to survive Extinction Vortex

9 Managing populations of waterfowl is difficult: Habitat Loss and Migratory Birds Birds need for habitat (places along whole route Wetlands are critical, yet are quickly disappearing Requires efforts to protect habitats along the flyways.

2) 3) Examples: Kudzu in Southeastern US (deliberate) Zebra

10 2. Introduction of Invasive Species Introduction can be either deliberate or accidental Nonnative species may have no natural 1) 2) 3) Examples: Kudzu in Southeastern US (deliberate) Zebra Mussels in the Great Lakes (accidental-ballast water) Ballast Water: Accidental

2. Invasive Species Once a species is introduced

the less likely the efforts will succeed.

11 2. Invasive Species Once a species is introduced to an area, it is difficult to turn back the clock and eradicate it. The more time before control measures are taken, the less likely the efforts will succeed. Biological Control sometimes has unintended consequences (i.e. Cane Toad in Australia)

12 3. Population Growth and Resource Use

insect-pollinated plants, including many

13 4. Pollution Examples: Pacific Ocean Garbage Patch: leads to loss of birds and fish Bee colony collapse syndrome Honeybees responsible for 80% of insect-pollinated plants, including many important crops like apples, almonds Dying due to? Parasites?

5. Climate Change Oceans are particularly vulnerable, due to ocean

Overfishing: Whales Prior to 1986, overharvest drove major whale

14 5. Climate Change Oceans are particularly vulnerable, due to ocean 6. Overexploitation Case Study: Overfishing Major commercial fishing methods. Modern methods enable increasing harvest of decreasing populations. Overfishing: Whales Prior to 1986, overharvest drove major whale populations to commercial extinction. Populations are in process of recovering since the 1986 International Whaling Ban.

15 Characteristics of Extinction Prone Species: low (e.g., blue whale, California condor) specialized (e.g., giant panda) feed at high (e.g., Bengal tiger) large (e.g., Asian elephant) limited (e.g., green sea turtle) limited (e.g., woodland caribou)

Characteristics of Extinction Prone Species Cont.

rhinos for horns) behaviors that contribute to

16 Characteristics of Extinction Prone Species Cont. fixed patterns (e.g., whooping crane) preys on (e.g., timber wolf) small (e.g. endemic island species) commercially valuable (e.g. rhinos for horns) behaviors that contribute to extinction (e.g., Carolina parakeet- flocks hover over injured bird.)

Past mass extinction events have also not been kind to large animals (i.e. dinosaurs).

17 Why are top consumers more vulnerable to extinction? Must be by a large amount of producers/lower consumers. Past mass extinction events have also not been kind to large animals (i.e. dinosaurs). Top Consumers also suffer from: Harmful concentrations of toxins get stored in body tissue such as fat. Due to the energy pyramid, toxins get up the food chain.

18 Worldwide Extinctions

19 Biodiversity Hotspots

Protecting Biodiversity Two approaches to species protection:

native habitats; advantage: it focuses on protecting sufficient land

wild species; approach: based on identifying & protecting endangered

species are at greatest risk & focuses attention on those species.

20 Protecting Biodiversity Two approaches to species protection: approach: aims to preserve balanced populations of species in their native habitats; advantage: it focuses on protecting sufficient land to protect ecological integrity & provide habitat for the majority of wild species; approach: based on identifying & protecting endangered species on a case by case basis; advantage: it identifies which species are at greatest risk & focuses attention on those species. consensus among conservation biologists is that protecting biodiversity requires both approaches

regulation for endangered species. For example- ban on ivory trade.

21 International Treaties on Biodiversity 1975: Convention on International Trade in Endangered Species (CITES) Signed by nearly countries International trade regulation for endangered species. For example- ban on ivory trade. 1992: Convention on Biological Diversity (BCD) Ratified by countries (not the US) Focuses on ecosystems

Pros- creates source of horn without killing of wild rhinos.

22 Example of an issue for consideration by CITES: International trade of rhino horn is banned by CITES, but poaching is a persistent problem. The next CITES delegation will consider whether to allow farming of rhino for their horns. Pros- creates source of horn without killing of wild rhinos. Cons- hard to determine source of horn and could facilitate the sale of horn from wild sources. Farming of crocodiles for their skins helped to preserve wild crocodile populations.

23 The Good News: More land is being protected over time

24 Protecting Biodiversity Unlike traditional parks & reserves, biosphere or nature reserves recognize local people's needs for access to sustainable use of resources in parts of the reserve.

25 U.S. Wilderness Areas US Wilderness Society estimates that a wilderness area should be at least in order to be protected from human activity. About of US land area is protected as wilderness: ¾ is in Alaska About of land area in lower 48 states is protected wilderness areas in lower 48 states: only are larger than 4,000 km 2 About 400,000 km 2 (150,000 mi 2 ) of public lands could still qualify as wilderness areas, but strong opposition to setting these lands aside exists from timber, mining, ranching, energy, and other interests Reducing Habitat Fragmentation When habitats are fragmented due to highways, animal bridges can help maintain the corridors. A wildlife bridge is planned for I-90 at Snoqualmie Pass

Government Agencies Involved: (NMFS) charged with protection of marine species;

26 Protecting Wild Species in the United States Endangered Species Act (ESA) of 1973 requires listing & protection of endangered & threatened species in US. Government Agencies Involved: (NMFS) charged with protection of marine species; charged with listing & California Condor protection of all other species; Florida panther

28 How Many Successes Have There Been in the US? Is it time for a new approach (i.e. Ecopragmatism)? Success Story: Bald Eagle

Chapter 9: Sustaining Biodiversity

Chapter 9: Sustaining Biodiversity Extinction Fossil record shows evidence of extinction as a natural process: background or natural rate of extinction: loss of species at a low rate mass extinction :