Lesson 7.2 Extinction and Biodiversity Loss

Transcription

1 Lesson 7.2 Extinction and Biodiversity Loss Biodiversity losses caused by humans are common in our history. Hunting and forest cutting drove the passenger pigeon once North America s most numerous bird into extinction. Do Now (pg 63): List an endangered species and a species that is now extinct. How do you think this happened? What effects does a species going extinct or becoming endangered have on a habitat?

2 Lesson 7.1 Our Planet of Life Biodiversity Describes the variety of life across all levels of ecological organization Speciation: process by which new species are generated Includes three types: Genetic diversity: Differences in DNA among individuals Species diversity: Variety of species in a given area Ecosystem diversity: Variety of habitats, ecosystems, communities Genetic Diversity Species Diversity Ecosystem Diversity

3 Lesson 7.2 Extinction and Biodiversity Loss Causes of Biodiversity Loss Habitat change and loss Invasive species Pollution Overharvesting Siberian tiger

4 Lesson 7.2 Extinction and Biodiversity Loss Habitat Change and Loss Greatest cause of biodiversity loss Organisms, adapted to their habitat, decline in population when the habitat changes. Habitat fragmentation: Patches of suitable habitat surrounded by unsuitable habitat In general, larger habitat fragments can support greater biodiversity than smaller fragments. Did You Know? Habitat change or destruction is the primary cause of population decline in more than 80% of threatened birds and mammals.

5 Lesson 5.4 Community Stability Invasive Species Nonnative organisms that spread widely in a community A lack of limiting factors such as predators, parasites, or competitors enables their population to grow unchecked. Not all invasive species are harmful. Did You Know? Although the European honeybee is invasive to North America, it is beneficial because it pollinates our agricultural crops.

6 Lesson 7.2 Extinction and Biodiversity Loss Invasive Species, Pollution, and Overharvesting Invasive species can out-compete and displace native species. Harmful chemicals and materials that make their way into habitats can poison people and wildlife. Once common in North America, the passenger pigeon is now extinct.

7 Overharvesting Overharvesting: the endangerment and extinction of species from overhunting and overfishing Extirpation: to destroy completely; kill off Poaching: the illegal practice of trespassing on another's property to hunt or steal game without the landowner's permission; poachers often hunt endangered/ threatened species

8 Lesson 7.2 Extinction and Biodiversity Loss Biodiversity at Risk Giant panda, an endangered species The current extinction rate is 100 to 1000 times greater than the natural background rate. In 2009, 1321 species in the U.S. were classified as endangered or threatened. Endangered: At serious risk of extinction Threatened: Likely to become endangered soon through all or part of its range

9 Lesson 7.2 Extinction and Biodiversity Loss Natural Biodiversity Loss Dinosaur extinctions were part of a mass extinction. Background extinctions: Naturally occurring extinctions, occurring one species at a time Mass extinctions: Events when extinction rates far exceed the normal background rate There have been five mass extinctions in Earth s history. Each time, more than 1/5 of all families and 1/2 of all species have gone extinct.

10 Video- answer questions on back of guided notes 7 Pets You Should Never Release into the Wild

11 Group Work complete in pg of journal 1. Look at figure 2 on pg 201. Describe what is happening to the tiger population. List 3 reasons why this is occurring. (Answers are in the description below, do not guess) 2. Pg 206 questions 1, 3, 4 3. Pg 211 questions 2, 3 4. Read the section Biodiversity, Tourism and Recreation on page 206. In 4 sentences or more answer: Do you think ecotourism is beneficial or harmful to biodiversity. Use evidence from the text

12 1.Which of the following is NOT a part of overall biodiversity? A. Species diversity B. Genetic diversity C. Individual diversity D. Ecological diversity 2.Which of the following increases species diversity? A. Extirpation B. Speciation C. Extinction D. Poaching 3.Globally, the leading cause of biodiversity loss is? A. Invasive species B. Poaching and overharvesting C. Pollution D. Habitat change and fragmentation 4.Most scientists think there is a strong connection between biodiversity loss and increasing human population size. How do you think an increased number of people affect biodiversity in your area? Consider each of the major causes of biodiversity loss in your answer.