There have been at least five extinction events in the long history of life on Earth, due to climate change and asteroid impact, and another more recent one,

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Course Learning Outcomes for Unit V Upon completion of this unit, students should be able to:

7. Discuss relationships between living organisms and nonliving factors in ecosystems. 7.1 Discuss a threatened organism’s biome and threats to its survival as a species. 7.2 Illustrate how human population growth and human activities can affect other species. 7.3 Explain what a keystone species is and how it relates to other species in its biome.

Required Unit Resources Chapter 15: Is the Human Population Too Large? Chapter 16: Conserving Biodiversity Chapter 17: The Human Footprint Unit Lesson Some people believe that people should, to quote the Bible, “fill the earth and subdue it” (Genesis 1:28, New International Version). What does this mean? Does it mean that we can take and use what we want and all that we want? There are certain requirements all organisms need to sustain life. For example, in order to meet our requirements for life, humans rely on organisms from other species. We know that we must have the obvious: oxygen, food, and water. We cannot synthesize the things that we need on our own, and we cannot make them for our use. We are not in this world alone, and we could not survive on our own; therefore, we must be willing to help take care of the world around us. In this unit, we will gain an understanding of the effects of a growing population of humans on a global, national, and local scale. We will also learn about conservation and about various types of environments and how they all interact. Are humans destroying the planet? Are we forcing other species into extinction? Is there anything that we can do, or is it simply too late? Our textbook states that our global population is nearing seven billion people (Belk & Maier, 2019). It is projected that our population will rise to 9.7 billion by the year 2050 (Worldometers, n.d.). Can the planet support that many people? It would seem that more people would be able to work more jobs, grow more food, and so on. Is more actually better? Is there enough land to grow enough food? It is possible that the world would be capable of supporting the population; however, we need to examine what a population is. A population consists of a group of an individual species within a given area (Belk & Maier, 2019). When we are examining population size, we also have to consider the population size of all other living species on Earth. It is not just humans that we need to consider—other species need space and resources as well. Are there limits to all populations? In nature, population sizes are limited depending on the competition for resources. There is only a certain amount of resources, and not all species survive for a full life span. Why does this competition not limit human population on a larger scale? Do only the fittest survive in a population of humans? Do we leave our less fit and less healthy to fend for themselves or leave them to die? In areas that do not have enough resources, do we leave those populations of people to struggle and die out? For humans to survive, we rely on organisms from other species. We need food, we need shelter, we need water, and we need oxygen. Since we rely so heavily on other organisms, we must learn how to conserve our

UNIT V STUDY GUIDE Ecology

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resources. If we do not, we could become like other species. Would we stop caring for our less fit and less healthy members? Would we become less human if our will to live and competition for resources became a fight for existence? Of course, we do not, but does this upset the balance of things? Extinction is a natural process; however, it is believed that humans are presently the greatest threat to biodiversity. Natural disasters, such as hurricanes, floods, volcanoes, and the like sometimes force species to go extinct; however, habitat destruction is one of the major forces driving extinction today. Why are we destroying habitats? With a growing human population, we need more space. When we clear-cut a forest or dam a river, we destroy the habitats of numerous organisms from a variety of species. When an organism’s habitat changes quickly or is destroyed, its population may not have time to adapt, forcing extinction. Alabama has about 25 miles of coast line between Mobile Bay and the Florida line. If you wish to read an interesting discussion about how human development affects the beach, please access Encyclopedia Alabama.

Along the Alabama beach lives a mouse, appropriately called the Alabama beach mouse (ABM). The mouse is a distinct species and has become endangered. It is now listed as such with the U.S. Fish and Wildlife Service (USFWS) (n.d.). This provides the mouse with federal protection, including preservation of its habitat. For a time, this listing halted all beachfront development along Alabama’s coast. Imagine how you would feel if you purchased an expensive piece of beachfront property and could neither sell it nor build a condominium on it. Basically, your property would now belong to the mouse. Since the endangered listing in 1985, the Wildlife Service has become a bit more flexible about development and takes development requests on a case by case basis (USFWS, n.d.). However, the

USFWS requires developers to adhere to certain rules such as protecting the dunes the mouse lives in, planting only native coastal vegetation, removing any free-roaming cats, not using poison, and properly disposing of garbage that might attract other vermin that would compete with the mouse. There is only so much space along the Alabama coast line. Can people and the ABM coexist? So far, federal regulations seem to have helped, and the ABM is holding its own. However, this is a microcosm of what is happening over the entire globe. Humans destroy habitats by introducing invasive species into an area (Belk & Maier, 2019). Invasive animals such as domestic cats and invasive, non-native plants make life difficult for the ABM. How many times have you traveled somewhere and seen a plant that you thought was beautiful? People travel and bring back plants from other areas. They plant the plants in their yard, seeds are dispersed to other areas by birds, wind, water, and insects, and soon the plant is growing unchecked in the wild. This is not that important, is it? It can be if the new plant outcompetes native plants. Take kudzu, for example. You may have seen kudzu growing along interstates and in areas that are not inhabited by humans. This vine is not native to the United States. It was brought over from Japan to help control erosion, but it grows out of control. It outcompetes other native plants and is not easy to kill.

The Alabama beach mouse (ABM) is an endangered species (Bureau of Land Management, 2015)

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Competition is natural; however, when new species are introduced into an area by humans, this is not natural. Ecosystems contain predators, consumers, decomposers, and producers. One provides a food source for the other—this is the web of life. Organisms within an environment have a special ecological niche; they have a certain role or job to perform. Think about it like a manufacturing warehouse with an assembly line. The first person has a very small job of placing one tiny screw in each product that passes. That does not seem very important; however, if that person does not insert the screw, the next person cannot do his job, and the next cannot do his job. It is like a domino effect. The same thing happens in nature. What if a very small organism that seems unimportant goes extinct? Other organisms may not be able to “do their job” or may not have a food source. The extinction of one organism could result in the extinction of numerous others. This is known as an extinction vortex (Belk & Maier, 2019). A good example of the effect caused by the removal of a keystone species is that of the wolf in Yellowstone National Park. Wolves were removed from the park in the 1920s; when they were brought back in the 1990s, it was clear that their impact on other park inhabitants and the ecosystem was widespread. Although there does not seem to be an intuitive connection, the absence of wolves in the park adversely impacted both beavers and elk, as well as warblers, insects, and even some fish. “Wolves in Yellowstone appear to fit the profile of a classic keystone species, one whose removal had numerous and surprising effects on biodiversity” (Belk & Maier, 2019, p. 357). Another great example is the experience of the African elephant (Kasnoff, n.d.). Elephants, being what they are, eat huge amounts of vegetation. However, they do not eat grass. Consequently, elephants keep the grasslands intact by eating the trees that threaten to take over. By preserving the grass, the elephants preserve the herbivores such as wildebeest, water buffaloes, and others upon which the lions, hyenas, and predators feed. One would not normally think that preserving elephants also preserves lions. Some species have so few numbers that genetic diversity among those living is very small. Can we save all species that are nearing extinction? What does it mean if a species is of concern or endangered? You will conduct an exploration activity for this unit in which you will learn about species that are in danger in your state or local area. You will learn about their importance, their habitat, how many currently exist, and what (if anything) is being done to protect their numbers.

Since kudzu was brought to the United States years ago to combat erosion, the vines have been growing wild, outcompeting other forms of plant life. The U.S. map at right shows areas that kudzu has infested. Below is a close-up of kudzu growing in the wild.

(Strongbad1982, 2007) (McCranie, 2014)

1994 report by the U.S. Department of the Interior and the U.S. Fish and Wildlife Service concerning the environmental impact of returning gray wolves to Yellowstone Park (U.S. Department of Interior, 1994)

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You will also learn that humans and other species live in a variety of biomes. The temperature and amount of precipitation in an area can be limiting factors for life. Still, some species live and thrive in cold climates, hot climates, wet climates, and dry climates. You will be able to determine the type of biome in which you live or have lived. In areas such as the tundra, many animals migrate or hibernate during the extreme cold seasons. In areas such as tropical rain forests, temperatures are moderate and precipitation is high, resulting in the greatest diversity of species on Earth. We hear a lot about saving the rainforests these days. What if you do not live near a rainforest? Does it matter to you if we save them or not? Does only what happens in your local environment matter? If we combine all the different biomes, we end up with a biosphere. If we break that word down, bio means life, and sphere means circle. So, it really is one big circle of life.

References Belk, C., & Maier, V. B. (2019). Biology: Science for life with physiology (6th ed.). Pearson. Bureau of Land Management. (2015). My public lands roadtrip- sunny Alabama shores for National Trails

Day! [Photograph]. Wikimedia https://commons.wikimedia.org/wiki/File:My_Public_Lands_Roadtrip- _Sunny_Alabama_Shores_for_National_Trails_Day!_(18581840295).jpg

Kasnoff, C. (n.d.). Asian elephant and African elephant.

http://www.bagheera.com/inthewild/van_anim_elephant.htm McCranie, J. (2014). Kudzu plants [Photograph]. Wikimedia

https://commons.wikimedia.org/wiki/File:KudzuPlants.JPG Strongbad1982. (2007). Kudzu [Graphic map]. Wikimedia

https://commons.wikimedia.org/wiki/File:Kudzu.PNG U.S. Department of Interior. (1994). The reintroduction of grey wolves to Yellowstone National Park and

Central Idaho [Photograph]. Wikimedia https://commons.wikimedia.org/w/index.php?title=File%3AThe_Reintroduction_of_Grey_Wolves_to_ Yellowstone_National_Park_and_Central_Idaho.pdf&page=1

U.S. Fish & Wildlife Service. (n.d.). Critical habitat for Alabama beach mouse.

https://www.fws.gov/daphne/es/abm/abm-ch.html Worldometers. (n.d.). Current world population. http://www.worldometers.info/world-population/ Learning Activities (Nongraded) Nongraded Learning Activities are provided to aid students in their course of study. You do not have to submit them. If you have questions, contact your instructor for further guidance and information. Learn About Your Biome Review Chapter 17, Section 17.2, “Terrestrial Biomes and the Human Footprint.” Which type of biome do you think you are living in? If you are unsure, or just for fun, type “which biome do I live in?” into an online search engine. If you want to see a map, type “biome” into the search engine and click “images.” Pick your biome, or another you are interested in, and type “grassland (or your type of biome) biome” into a search engine. Click a few links that look appealing to you, and consider the following questions as they pertain to the biome you chose:

• What kind of animals live in this biome? • What kind of people live there?

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• Is the biome threatened by humans? • Do you recognize any plants from this biome?

Write a brief paper detailing your findings. If you have questions, contact your instructor to discuss them.