CHAPTER 11 BIODIVERSITY: PRESERVING SPECIES

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1 CHAPTER 11 BIODIVERSITY: PRESERVING SPECIES 74 Chapter Objectives Discuss biodiversity and the species concept Summarize some of the ways we benefit from biodiversity Characterize the threats to biodiversity Evaluate endangered species management Scrutinize captive breeding and species survival plans Key Terms Breeding programs Critical habitat Endemic species Flagship species Indicator species Keystone species Mass extinction Overharvesting Phylogeny Scientific nomenclature Taxonomy Umbrella species Concept Review 11.1 Biodiversity and the Species Concept Biodiversity has three components: o genetic diversity genes within a species. o species diversity the number of species in a community. The total number of species in the community is its richness. The abundance of individuals within each species is its evenness. o ecological diversity the number of niches, trophic levels, and ecological processes. Carolus Linnaeus began the system of classification based on the appearance of adult organisms. The phylogenetic species concept examines the cladistic or branching relationships in the species development. The evolutionary species concept takes into account the changes that have taken place over time using genetic information. By using genome information, scientists can analyze individuals in a population. This becomes especially important when breeding animals in captivity to increase an endangered or a threatened population.

2 Current estimates of the number of species are that there are 1.6 million species today. This is probably only a fraction of the actual number of species that exist. Some taxonomists estimate that there are 30 million species of tropical insects alone. Seventy-six percent of all known species are invertebrates, concentrated mainly in the tropics. Biodiversity hot spots are areas that are at high risk due to human disruption and potential loss of biodiversity How Do We Benefit from Biodiversity? Improvements in our food supplies have come from the diverse array of edible organisms. More than half of our medicines are either derived from or modeled after compounds found in living organisms. The biogeochemical cycles link us to other organisms without them, we could not survive. The more diverse an ecosystem is, the more stable it is. Biodiversity also has cultural and psychological ties, which may be linked spiritually and emotionally. Existence value simply knowing that a species exists is the reason some species are valued and protected What Threatens Biodiversity? Extinction is the elimination of a species. Extinction is a normal process that occurs naturally at a rate of one species lost per decade. Periodically mass extinctions have occurred. Scientists theorize that these mass extinctions have been due to climatic change. Human activities have accelerated the rate of extinction by altering ecosystems. Biologist E. O. Wilson summarized the human threat to biodiversity using the acronym HIPPO (Habitat destruction, Invasive species, Pollution, Population [human], and Overharvesting). o Humans convert habitat to other uses, forcing the native species to small, scattered areas that are not sufficient to maintain the population. o Invasive species are organisms that have no predators in the area. As a result, they force out the native species. Invasive species may be introduced into an ecosystem accidentally or intentionally by humans. o Pollutants, including pesticides, kill organisms and populations, even though they are not the intended targets. 75

3 o Human population growth removes habitat through expansion and changing of the ecosystem to other uses. o Overharvesting depletes populations as they are harvested for food or are exploited for other purposes Endangered Species Management 76 Few people understand what biodiversity is or why it is important. Governments enact legislation designed to protect species diversity. By the 1890s, most states had enacted legislation to conserve resources and protect species, regardless of their usefulness to humans. Endangered species are those considered most at risk for extinction. Threatened species are those that are likely to become endangered. Vulnerable species are those that are rare or have been depleted to a level that puts them at risk. Recovery plans are developed for each species that is placed on the endangered or threatened list. Certain types of species are given more scrutiny and consideration than others. o Keystone species are those members of a community that determine the essential characteristics of the community. o Indicator species are a measure of a community s overall ecological health. o Umbrella species are those species that require large areas of undisturbed habitat for success. o Flagship species are those species that cause an emotional reaction in people. The Endangered Species Act regulates a variety of activities, including hunting and trapping, collecting, and transporting and selling various species. Habitat Conservation Plans are agreements with private landowners to benefit certain species by regulating the habitat disruption in the area. The Convention on International Trade in Endangered Species (CITES) was developed to protect endangered species and related products that were being traded internationally Captive Breeding and Species Survival Plans Breeding programs are an attempt to save threatened and endangered species. When such programs are successful, endangered species can be reintroduced into the wild. Some organisms do not breed in captivity, so endangered populations are maintained in captivity as a result of habitat destruction in their native habitat.

4 Zoos also work in native habitats to preserve and protect wild populations. 77 Class Time: Biodiversity and habitat destruction make up approximately 10 percent of the Acorn outline. While everyone has heard of endangered species and the destruction of the tropical rainforest, can your students explain why an organism becomes endangered or why extinction is a natural process? Can they explain why the management of forests and other ecosystems is important to our survival? Allow 5 days to investigate and discuss this chapter. Students should begin to take note of the cyclical nature of the course at this point. Approach and Tips Taxonomy and classification form the basis of this chapter. Begin with the work that the early taxonomists, such as Linnaeus, did and continue the discussion using information based on the progression of scientific knowledge with new discoveries in genetics and DNA research. Point out that habitats and species are being lost faster than scientists can identify them, particularly in tropical areas. Discuss the danger in removing or eliminating an organism from a habitat before we fully understand the interrelationship among the organisms in the community. Review the evolution of a well-known species, such as the horse or dinosaur, and discuss how each changed in response to changing environmental conditions. If time permits, have students research the occurrence of mass extinctions and what types of climatic changes were responsible. Several examples of invasive species are discussed on pp Whether they were taken into an area for a specific purpose or were transported to an area unintentionally, the result is the same. Without population controls, these invaders displace the native species. Have students relate the characteristics of an invasive species to an r-strategist or a K-strategist species. Refer students to the essay on p. 236, What Can You Do?. Discuss the harvesting of some commercial products in unsustainable ways. Have students make suggestions regarding what they can or will do differently to reduce their dependence upon unsustainable commerce. Ask them what organisms they purchase that are human threatened species and why these species are threatened by human activities. Many regulations and laws have been established to protect species and habitats from human activity and resource depletion. The Endangered Species Act and CITES are only two. While including these in your discussions, also refer

5 students to chapter 24, which gives much more information on and insight into the actions of governments to protect the environment. 78 Applications Endangered Species Zoo Project Procedure: 1. Call the local zoo to get a list of endangered animals they have at the zoo. 2. Assign each student a different animal to study 3. Have the students research the following information on their assigned animal: a. What does the animal eat? b. How much food is required per day? c. How does the animal obtain its food? d. What adaptations does the animal have to survive? e. What captivity problems has this animal encountered? f. When does the animal eat? g. What temperature range can this animal withstand? h. What is the general vegetation of this animal s natural habitat? i. At what height and depth in the habitat is this animal found? j. What other animals would share this habitat? k. In what trophic level of the food chain would this animal be found? l. Why is this animal on the endangered species list? m. What steps are being taken to help this animal survive? n. Why is it important to protect this animal? 4. After researching, take the students to the zoo or have them go on their own. While at the zoo have the student observe the animal for 15 minutes. Record what the animal is doing. (If the animal is asleep, come back later). 5. Have the student take a digital picture of the zoo s habitat for the animal. 6. Students should then critique the animal s zoo habitat using the information they obtained while researching the animal s natural habitat. Have the students include in their critique the vegetation, size and quality of containment, number of animals in the containment and the students personal reaction to the type of habitat it currently has. 7. After the zoo, have the students get a piece of poster board and design a better habitat. Have the students use the research questions and the information they obtained while at the zoo to help them create their new habitat. 8. Finally, have the students answer the following questions:

6 a. What is the survival prospect of this animal? b. What is the value of a zoo for this animal? c. Is this animal able to breed in captivity, and has captive breeding been successful? d. What are the negative and positive aspects of the zoo for your animal? 79 Common Mistakes and Misconceptions Be sure to stress to students that there are trade-offs to all environmental decisions. For example, it is real easy, while sitting in your living room, to say save the rainforest. However, it is much more difficult to convince the farmer in the developing nation to sacrifice his/her starving family for the rainforest. Many students have a perfect world mentality, and bringing up these kinds of issues in either a class discussion or debate is a good way for them to see that there are no easy answers to environmental problems. Suggested Website: The information at is a wonderful way for students to find the 25 hotspots on the planet. Hotspots are areas where biodiversity is extremely high and is also being threatened. The website has a map of the hotspot, the type of ecosystem found there, plant and animal species that are endemic, human induced reasons for a decreasing biodiversity, and what is being done to protect the hotspot. Question 1. Identify an invasive species in your area. What is its native habitat? How did it get established in your area? Describe what steps are being taken to manage or eliminate the organism. Why is it damaging the community?