Chapter 10 Section 1 What Is Biodiversity Objectives

Chapter 10 Section 1: What Is Biodiversity

Objectives Describe the diversity of species types on Earth, relating the difference between known numbers and estimated numbers. u List and describe three levels of biodiversity. u Explain four ways in which biodiversity is important to ecosystems and humans. u Analyze the potential value of a single species. u

A World Rich in Biodiversity u I. What is Biodiversity? u A. A World Rich in Biodiversity u Biodiversity – short for biological diversity – refers to the number and variety of different species in a given area u certain areas of the planet such as tropical rain forests contain an extraordinary variety of species

u Study of biodiversity starts with the unfinished task of cataloging all the species that exist on Earth u actual number of species is unknown – probably somewhere greater than 10 million u many unknown species exist in remote wilderness, deep in the ocean, and even in cities u some types of species are harder to study and receive less attention than large, familiar species u less is known about insects and fungi than is known about trees and mammals

Unknown Diversity

u 1. 3 levels of biodiversity species diversity – all the differences between populations of species as well as between different species u this is what is most often meant by biodiversity

u 2. 3 levels of biodiversity ecosystem diversity – refers to the variety of habitats, communities, and ecological processes within and between ecosystems u 3. genetic diversity – all the different genes contained within all the members of a population gene – a piece of DNA that codes for a specific trait that can be inherited by an organism’s offspring

B. Benefits of Biodiversity u Biodiversity can affect the stability of an ecosystem and the sustainability of populations. u Many ways humans clearly use and benefit from the variety of life-forms on Earth u Species are connected to ecosystems

B. Benefits of Biodiversity u we depend on healthy ecosystems to ensure a healthy biosphere that has balanced cycles of energy and nutrients u each species plays an role in keeping the cycles balanced, when one species disappears from an ecosystem a strand in a food web is removed

u keystone species – species that are particularly critical to the functioning of an ecosystem The grazing and burrowing activities of prairie dogs improve forage quality, conserve water, and improve the soil in the Great Plains. How?

Sea Otters as an Example of a Keystone Species

Sea Otters classic keystone species 1. European and Russian trappers hunt sea otters to near extinction in the 18 th and 19 th centuries. 2. The decline of the sea otters, which are essential to keeping sea urchins in check, allows sea urchin populations to explode. 3. The burgeoning sea urchins feast on and decimate the kelp beds, which are critical habitat for spawning fish. 4. Fish begin to decline for lack of spawning habitat; this affects fishermen's catches. 5. Finally, an international treaty is enacted to protect sea otters. 6. In areas where the otters recovered, urchin populations are once again kept down, the kelp beds recover, fish nurseries recover, and fish catches rise again.

u the level of genetic diversity within a population is a critical factor in species survival u genetic variation increases the chance that some members of a population will survive environmental pressures or changes u small or isolated populations are less likely to survive u when a population shrinks its genetic diversity decreases like passing through a bottleneck u if the population restores its numbers, there will be inbreeding with fewer varieties of genes, making the new population more susceptible to genetic diseases

Species and Population Survival

Medical, Industrial, and Agricultural uses u Organisms on earth are used for food, clothing, shelter, and medicine u 1/4 of the drugs prescribed today come from plants u antibiotics are derived from chemicals found in fungi u undiscovered and poorly studied species represent a source of potential products

Aspirin originally was derived by boiling the bark of the white willow tree to extract acetylsalicylic acid Rosy Periwinkle native to Madagascar, has yielded compounds used to treat Hodgkin's disease and leukemia. Paclitaxel (Taxol) is a valuable pharmaceutical compound used to treat cancer, Alzheimer's and heart disease – Derived from the Pacific Yew

Humans benefit from biodiversity every time they eat most of the crops produced around the world originated from a few areas of high biodiversity u most new crops are hybrids – crops developed by combining genetic material from other populations u reduces genetic diversity of wild-types u depending on too few crops for food is risky – especially when wiped out by disease – it can lead to famine u

Foods and their origins

Further Benefits of Biodiversity u u u Ethics, Aesthetics, and Recreation Some people believe we should preserve biodiversity for ethical reasons species and ecosystems have a right to exist whether or not they have any other value some cultures and religions feel each organism on Earth is a gift with a higher purpose aesthetics or personal enjoyment is another reason to preserve biodiversity keeping pets, camping, picking wildflowers, watching wildlife

u ecotourism – a form of tourism that supports the conservation and sustainable development of ecologically unique areas u some regions earn the majority of their income from ecotourism

Bellringer

II. Biodiversity at Risk u A. Current Extinctions u Scientists are warning that we are in the midst of another mass extinction u the rate of extinction is estimated to increase by a multiple of 50 since 1800

Species prone to extinction Generalist species - Species with large populations that adapt easily to many habitats – cockroaches and rats – are not likely to become extinct u specialist species -species with small populations in limited areas – can easily become extinct u species especially at risk are those that migrate, need large or special habitats, and those exploited by humans u

Specialist Species and Generalist Species Niches – Which is more prone to extinction?

Cockroach

Categorizing Species IUCN Red List u Endangered species – a species likely to become extinct if protective measures are not taken immediately u Threatened species – a species that has a declining population and that is likely to become endangered if it is not protected u Other categories exist for legal and biological purposes. Ex: Least concern…. Not Evaluated…. . Vulnerable u http: //www. iucnredlist. org

B. How Do Humans Cause Extinctions? As human population growth has accelerated the past 2 centuries, so has the rate of extinctions. u The major human causes of extinction use the acronym HIPPO u -H – Habitat Destruction and Fragmentation u -I – Invasive Species u -P – Population u -P – Pollution u -O – Overharvesting u

Habitat Destruction and Fragmentation u As the human population grows, we use more land for our resources, homes, food, etc. u In the process we destroy or fragment the habitats of other species

Invasive Species u invasive or exotic species – a species not native to a particular region – 4 wheelers in the woods open up a forest to these they threaten native species because they have no natural defenses against the exotic species u -the exotic species also has no natural predators to keep its population in check and so it frequently grows out u of control and pushes the native species out u -compete for the same resources u

Population u human overpopulation

Pollution u Pesticides, cleaning agents, drugs, fertilizer, other chemicals used by humans make their way into food webs around the globe u long-term effects of these chemicals are still unknown u Some do cause animal deaths, sterility, death of young, etc. u American bald eagle is an example DDT – Soft Shells

Overharvesting u excessive hunting and harvesting of species can also lead to extinction u Some used as pets, houseplants, wood, food, or herbal medicine – Good article in Jan. 2010 Natl. Geographic Magazine u many countries have laws to regulate hunting, fishing, harvesting, and trade of wildlife

u poaching – the crime of illegally hunting certain animals u in poor countries, local species are a source of food, medicine, or income

C. Areas of Critical Biodiversity u Some parts of the world contain a greater diversity of species than others u Endemic species – species that are native to and found only within a limited area u The number of endemic species is an indicator of overall biodiversity

Tropical Rain Forests the remaining TR forests cover about 7% of the Earth’s land surface but it is estimated to contain over half the world’s species – most of which have never been described u unknown numbers of species are disappearing as tropical forests are cleared for farming or cattle grazing u they are among the few places some native people maintain traditional lifestyles, so there is a cultural impact too u

Coral Reefs and Coastal Ecosystems u -occupy a small fraction of marine environment yet contain the majority of the biodiversity there u -provide millions of people with food and tourism revenue u -protect coasts from waves and are sources of new chemicals u -poorly studied and not well protected by laws

Coral Reefs and Coastal Ecosystems u 60% are threatened by human activities such as overfishing and pollution u Similar threats affect coastal ecosystems such as swamps, marshes, shores, and kelp beds

Islands -when an island rises from the sea it is colonized by a limited number of species from the mainland – Primary Succession u -these species evolve over time to new species – thus islands hold a very distinct but limited number of species u -Hawaiian Islands have 28 species of an endemic family of birds but are endangered by competition from exotic species Hawaii’s Honeycreepers u

Honeycreepers The honeycreepers are threatened by recently introduced predation competition parasitism degradation of habitat infectious disease u

Biodiversity Hotspots u biodiversity hotspots – the most threatened areas of high species diversity on Earth u 25 areas have been identified by international conservationists u have high numbers of endemic species that are also threatened by human activities u include mostly tropical rainforests, coastal areas, and islands

Endangered Natural Capital: Biodiversity Hotspots

Biodiversity in the United States u three of the biodiversity hotspots are partly within US borders u the US includes a wide variety of unique ecosystems including Florida Everglades, California coastal region, Hawaii, Midwestern prairies, forests of the Pacific northwest

u u the US includes a wide variety of unique ecosystems including Florida Everglades, California coastal region, Hawaii, Midwestern prairies, forests of the Pacific northwest -US holds unusually high numbers of species of freshwater fishes, mussels, snails, and crayfish – Especially TN -threats are use of land for agriculture or housing, dam construction, overuse of water, destructive recreation, and mining all stems from local human population growth

III. The Future of Biodiversity u A. Saving Species One at a Time u Captive-breeding programs – breeding species in captivity with the hope of reintroducing populations to their natural habitats u California condor

Preserving Genetic Material u Germ plasm – any form of genetic material contained within the reproductive, or germ, cells of plants and animals u Germ plasm banks store germ plasm for future use in research or speciesrecovery efforts u material may be stored as seeds, sperm, eggs, or pure DNA u Heirloom Vegetables

Zoos, Aquariums, Parks and Gardens u u u zoos originally were to put animals on display, but now they are being used to house the few remaining members of a species – perhaps the last hope for survival zoos, wildlife parks, aquariums, and botanical gardens are living museums of the world’s biodiversity However, they don’t have the resources or knowledge to preserve more than a fraction of the world’s rare and threatened species

u u u Ultimately, saving a few individuals does little to preserve a species captive species may not reproduce or survive again in the wild small populations are vulnerable to infectious disease and genetic disorders caused by inbreeding

B. Preserving Habitats and Ecosystems The most effective way to save species is to protect their habitats u difficult because it means preserving or managing large areas u Conservation strategies most conservationists now give priority to protecting entire ecosystems rather than individual species because you can save more species this way u

u to protect the most biodiversity, conservationists focus on the hotspots u identify areas of native habitat that can be preserved, restored, and linked into large networks u promote products that have been harvested with sustainable practices such as shade grown coffee

More study needed u need for more serious study of ecosystems – such as how large does a protected preserve have to be to maintain a certain number of species u how much fragmentation can a particular ecosystem tolerate

C. Legal Protections for Species – US Laws u Endangered Species Act – 1973 – has been amended several times since designed to protect plant and animal species in danger of extinction

u 1 -USFWS – US Fish and Wildlife Service must compile a list of all endangered and threatened species in the US

u as of 2005, 1, 272 species were listed as endangered or threatened u dozens more are considered for the list each year u difficulty in getting species listed u Field Trip Earth http: //fieldtripearth. org/

u 2 -protects listed species from human harm u anyone who harms, buys, sells any part of these species is subject to a fine or imprisonment u http: //www. earthsendangered. com Prickly Shark

u 3 -prevents the federal government from carrying out any project that jeopardizes a listed species u Recovery and Habitat Conservation Plans Construction of the Tellico dam was delayed when a small endangered fish called the snail darter was discovered on the Little Tennessee River. Dam opponents brought a lawsuit under the Endangered Species Act. The Endangered Species Committee (a. k. a. the "God Squad") decided to uphold the protection of the snail darter costing TVA approx. $78 million

u 4 th ESA provision- the USFWS must prepare a species recovery plan for each listed species u -plans propose to protect or restore habitat for each species u -controversial in the attempt to restrict human uses of land u developers may be prohibited from building on their own land u lose income on land when land uses are restricted u many object when their interests are placed below that of another species

Compromise in a habitat u conservation plan – a plan that attempts to protect one or more species across large areas of land through trade-offs or cooperative agreements

D. International Cooperation u At the global level the International Union for the Conservation of Nature and Natural Resources (IUCN) u facilitates efforts to protect species and habitats u -a collaboration of almost 200 government agencies and over 700 private conservation organizations

u IUCN publishes Red Lists of species in danger of extinction around the world u -advises governments on ways to manage their natural resources u -works with groups like the World Wildlife Fund to sponsor conservation projects

International Trade and Poaching u IUCN produced a treaty called CITES (Convention on International Trade in Endangered Species) u CITES treaty was the first effective effort to stop the slaughter of African elephants

u Earth Summit – more than 100 world leaders and 30, 000 other participants met in 1992 in Rio de Janiero, Brazil u most ambitious effort to tackle environmental issues on a worldwide scale u The United Nations General Assembly in December agreed to a new Earth Summit in 2012. The Summit will be held in Brazil and will focus on four areas: u The Green Economy u Emerging Issues u Sustainable Development Governance

u Biodiversity Treaty – goal is to preserve biodiversity to ensure the sustainable and fair use of genetic resources in all countries u took many years to be adopted by the US, because of impact on economic and trade agreements u should take into account any impacts on biodiversity

Private Conservation Efforts u many private organizations work to protect species worldwide – often more effective than government agencies u World Wildlife Fund – encourages the sustainable use of resources and supports wildlife protection Nature Conservancy – helped purchase many acres of habitat preserves in 29 countries Conservation International – helps identify biodiversity hotspots and develop ecosystem conservation projects in partnership with other organizations and local people Greenpeace International – organizes direct and sometimes confrontational actions to counter environmental threats u u u

E. Balancing Human Needs Attempts to protect species often come into contact with the interests of the world’s human inhabitants u An endangered species represents a source of food or income or it may not seem valuable to those who do not understand the species’ role in an ecosystem u An important part of protecting species is making the value of biodiversity understood by more people u