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Transcript
Ch. 10 - Biodiversity Sect. 1 Objectives • Describe the diversity of species types on Earth, relating the difference between known numbers and estimated numbers. • List and describe three levels of biodiversity. • Explain four ways in which biodiversity is important to ecosystems and humans. • Analyze the potential value of a single species. Biodiversity(biological diversity) – the number of different species in a given area • Plants – Trees, shrubs, flowers, weeds • Animals – Mammals, insects, fish, crustaceans • • • • Fungus Insects Bacteria Etc. How many are there? • 1.7 million species are known – Most are insects • 10 million species are estimated to exist Levels of Diversity • Species diversity – number of different species in an area • Ecosystem diversity – variety of habitats, communities • Genetic diversity – number of genes contained in all members of a population What makes everything different? • Genes (DNA) – code for different traits or characteristics that can be inherited – Everyone's is different (unless you are an identical twin) Why is Biodiversity Important? • All species are dependant on other species and are depended on by others • Everyone fits in the food web/chain • If you remove one link, all the others will fall Keystone species – a species that is critical to the functioning of the ecosystem because it affects the survival and abundance of many other species • – one species that many others depend on Ex: Sea Otters • 1. Otters killed for fur • 2. Sea urchin population grew • 3. Kelp disapeared Ex: Prairie dogs Biodiversity and Survival • More genetic diversity means the population has a greater chance of surviving environmental changes. (ie: global warming) • Ex: Hemophilia Biodiversity and Humans • More organisms the more things for us – Food – Antibiotics – Clothing – Shelter – Chemicals Ecotourism – tourism that supports the conservation and sustainable development of ecologically unique areas • Has become very popular lately Sect. 2 Objectives • Define and give examples of endangered and threatened species. • Describe several ways that species are being threatened with extinction globally. • Explain which types of threats are having the largest impact on biodiversity. • List areas of the world that have high levels of biodiversity and many threats to species. • Compare the amount of biodiversity in the United States to that of the rest of the world. All species are considered one of these: depending on their natural numbers • Extant • Threatened • Endangered • Extinct Extant – living animals Threatened – still abundant in its natural habitat but is likely to become endangered because of their declining numbers Endangered – so few individuals that they are likely to become extinct Extinct – no known individuals still alive Species most at risk • Animals that are more likely to become extinct are those that: – Have small populations – Migrate – Need large or special habitats – Are exploited by humans • Currently humans are the greatest cause of extinctions! Species can be threatened by • Humans – Hunting – Loss of habitat (75% of current extinctions) • • • • • Deforestation Damming Burning Growing cities Pollution – Poaching – Invasive species • Natural Causes – Interbreeding – Natural Disaster – Disease Exotic – not native to an area • When brought to a new area exotic species can cause the extinction of other species they out compete • Ex: Fire Ant – Horny Toads (Desert Horned Lizard) eat ants – Fire ants (exotic species) kill horny toads. – Horny toads are now threatened! Generalist Species • Species with a broad niche, can survive in many different places HUMANS Often are invasive species Specialist Species Species with a narrow niche. Only live in a small range of environmental factors Fewer if these because they can become extinct more readily Critical Areas • Tropical Rain Forests – over half the worlds species live here – Most species have not been named, yet – But, lots of these are disappearing • Due to habitat destruction by humans! • Coral Reefs and Coastal areas • Islands – why? Biodiversity Hotspots – high number of endemic species but are threatened by humans Madagascar • Biodiversity Hotspot – Endemic Species • 80% of plants • 91% of reptiles • 100% of lemurs (10% of worlds primate population) • Only 18% of the original forests remain!! Sect. 3 Objectives • List and describe four types of efforts to save individual species. • Explain the advantages of protecting entire ecosystems rather than individual species. • Describe the main provisions of the Endangered Species Act. • Discuss ways in which efforts to protect endangered species can lead to controversy. • Describe three examples of worldwide cooperative efforts to prevent extinctions. Ch. 10 Ecolog • Read in your book, in Sect. 3, about the following ways to save species. In your Ecolog write a brief description of each! – Captive-Breeding programs – Preserving Genetic Material – Zoos, etc. – Conservation Strategies • Write a paragraph about why it is important to save species and the biodiversity around the world.