Eco-chapter1 (1) PDF

**Chapter 1: The Study of Ecology** **Overview**: Ecology studies the interactions among organisms and their environment. Objects of study include interactions of organisms with each other and with abiotic components of their environment. Topics of interest include the biodiversity, distribution,...

**Chapter 1: The Study of Ecology** **Overview**: Ecology studies the interactions among organisms and their environment. Objects of study include interactions of organisms with each other and with abiotic components of their environment. Topics of interest include the biodiversity, distribution, biomass, and populations of organisms, as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, and the non-living components of their environment. **Chapter objectives:** At the end of the chapter the students should able to: 1. discuss the level of ecological study. 2. discuss the application of ecology to other sciences. 3. use scientific methods in the study of ecology. 4. determine the importance of ecology upon knowing its basic ecological ideas. **LESSON 1.1: Definitions of Ecology** With caveats in mind, consider definitions of ecology. In the 1860s, Ernst Haeckel, combined the term oikos---a place to live, home, habitat---with logia---discourse, study---to coin the word "ecology." In the 1890s Ellen Richards included humans and harmony, quite a modern view. Variations over the years. **Objectives** **At the end of the lesson the students should:** 1. define the term ecology. 2. describe the development of the scope of ecology in terms of ecologist views and consideration. **Content:** Table 1.1. History of Ecology Ecologist Year Definition of Ecology -------------- ------- ------------------------------------------------------------------------------------------------------ Haeckel 1860s The total relations of an organism to its organic and inorganic environment Richards 1890s Living in harmony with the environment, first including the human species Elton 1920s Scientific natural history Odum 1960s The study of structure and function of nature, including the human species Andrewartha 1960s The scientific study of the distribution and abundance of organisms Krebs   The scientific study of the interactions that determine the distributions and abundance of organisms Molles 1990s The study of relationships between organisms and the environment Eltis 2010s Life in context Pope Francis 2015 The relationship between living organisms and the environment in which they develop Table above shows various views of ecology. Each of these definitions has merit, but the first two and the last two are closest to the way the term is applied. We humans have become prominent in ecology, locally to globally. No modern treatment of ecology is complete without a strong dose of anthropology. The definition by Andrewartha has been widely quoted, but focusing merely on distribution and abundance reduces ecology to mapping, which is why Krebs modified this definition. The Pope's definition from his 2015 Encyclical includes the interesting idea of development, which can be taken to mean short-term development like embryogenesis and growth, plus long-term development like evolution. Overall, the definition by Eilts is perhaps the most general and engaging. First and foremost, the most important concepts in ecology are about relationships, plus all of life, the whole environment, the processes of living and development, and, above all context. And in today's world, harmony. But also consider, "Poetry is the subject of the poem" (Wallace Stevens, 1937) and perhaps "Ecology is what ecologists do." With these in mind, we strive in the remainder to define a theoretical form of ecology through examples and demonstrations, representative models and symbols, patterns and explanations, and lessons. From its early days, ecology has been in part a theoretical-- mathematical science, and it is now also a computational science. Mathematical theory arises where systems are relatively simple. In our modern era, computation can address somewhat more complex systems, though creating computations on complex systems that satisfy the basic tenets of science is still problematic. For very complex systems, narrative is all we have available **Summary:** Ecology has strong ties to other sciences. The complex interaction taking place within the system involves all sorts of physical and biological processes.This dependency makes ecology an interdisciplinary science. **Enrichment; ( Limit your answer in 1 page only)** 1. Is ecology a science? 2..What is the summary definition of ecology from different views of ecologist since 1860s to 2015? 3. Enumerate some sciences and explain how they are related to ecology. Suggested Readings: "Focus on Ecology 1.1: Ecology has Complex Roots". Elements of Ecology by RL.Smith and TM. Smith **Lesson1.2: Levels of Ecological Studies and** **Application** **Introduction:** Ecology covers a vast range of topics and can be viewed on multiple levels. These levels include (1) individual organism, (2) population ecology, (3) community ecology, (4)  and global ecology. Ecology the study of organisms, populations, and communities as they relate to one another and interact in the ecosystems they comprise. In ecology, ecosystems are composed of organisms, the communities they comprise, and the non-living aspects of their environment. Its processes are those that sustain and regulate the environment..Ecological areas of study include topics ranging from the interactions and adaptations of organisms within an ecosystem to the abiotic processes that drive the development of those ecosystems. **Objectives:** **At the end of the lesson, the students should be able to:** 1.relate ecology with organismal interaction in the ecosystem. 2\. explain the level and scope of ecological study. 3\. appreciate the applications of ecological knowledge. **Content:** Ecology is the study of the interactions of living organisms with their environment. Within the discipline of ecology, researchers work at four specific levels, sometimes discretely and sometimes with overlap. These levels are organism, population, community, and ecosystem. In ecology, ecosystems are composed of dynamically-interacting parts, which include organisms, the communities they comprise, and the non-living (abiotic) components of their environment. Ecosystem processes, such as primary production, pedogenesis (the formation of soil), nutrient cycling, and various niche construction activities, regulate the flux of energy and matter through an environment. These processes are sustained by organisms with specific life-history traits. The variety of organisms, called biodiversity, which refer to the differing species, genes, and ecosystems, enhances certain ecosystem services. image Figure 1.2.1 **Levels of ecological study**: Ecologists study within several biological levels of organization, which include organism, population, community, and ecosystem. Ecology covers a vast range of topics and can be viewed on multiple levels. One level is that of the* individual organism*--- a single bacterium, an individual wolf pup. This includes individual behavior and physiology, with behavior as part of ecology. *Population ecology *covers groups of organisms of the same species---a bison herd or a grove of maples. *Community ecology* looks at how different populations interact, and the communities examined can be quite large. Above this level is *ecosystem ecology*, which examines how different communities interact with their environments. Finally, there is *global ecology*---ecology of the planetary ecosystem. Individual ecology Single organisms, behavior, and physiology -------------------- -------------------------------------------- Population ecology Groups of organisms from a single species Community ecology Populations of interacting species Ecosystem ecology Multiple communities and the environment Global ecology The planet as a biosphere In essence, ecologists seek to explain: - life processes - interactions, interrelationships, behaviors, and adaptations of organisms - the movement of materials and energy through living communities - the successional development of ecosystems - the abundance and distribution of organisms and biodiversity in the context of the environment Figure1. 2.2 Levels of Biological Organization There are many practical applications of ecology in conservation biology, wetland management, natural resource management (agroecology, agriculture, forestry, agroforestry, fisheries), city planning (urban ecology), community health, economics, basic and applied science, and human social interaction (human ecology). Organisms and resources comprise ecosystems which, in turn, maintain biophysical feedback mechanisms that moderate processes acting on living (biotic) and nonliving (abiotic) components of the planet. Ecosystems sustain life-supporting functions and produce natural capital, such as biomass production (food, fuel, fiber and medicine), the regulation of climate, global biogeochemical cycles, water filtration, soil formation, erosion control, flood protection, and many other natural features of scientific, historical, economic, or intrinsic value. There are also many subcategories of ecology, such as ecosystem ecology, animal ecology, and plant ecology, which look at the differences and similarities of various plants in various climates and habitats. In addition, physiological ecology, or ecophysiology, studies the responses of the individual organism to the environment, while population ecology looks at the similarities and dissimilarities of populations and how they replace each other over time. Finally, it is important to note that ecology is not synonymous with environment, environmentalism, natural history, or environmental science. It is also different from, though closely related to, the studies of evolutionary biology, genetics, and ethology. **Ecology** is the study of how living things interact with each other and with their environment. Although it is a science in its own right, ecology has areas of overlap with many other sciences, including biology, geography, geology, and climatology. It is also closely related to genetics and ethology (the study of animal behavior). In addition, evolutionary concepts of adaptation and natural selection are the cornerstones of modern ecological theory. Some of the phenomena that ecologists study include the interactions of organisms, the flow of energy and recycling of matter through living things, and the biodiversity and distribution of organisms relative to the environment. There are many practical applications of ecology. Among others, they include the conservation of endangered species natural resource management, urban planning, and human health. **Summary:** Ecology is the study of the interactions of living organisms with their environment.These levels are organism ecology, population ecology, community ecology, and ecosystem ecology. Knowledge in ecology have many practical applications in conservation biology, wetland management, natural resource management (agroecology, agriculture, forestry, agroforestry, fisheries), city planning (urban ecology), community health, economics, basic and applied science, and human social interaction (human ecology **Enrichment:** 1. Explain the coverage of each level of ecological study. 2. Discuss the levels of biological organization. 3. Explain why ecological organization is a part of a biological organization? 4. Cite one exact application of ecological management in the following Conservation Biology: a\. Agriculture b\. Forestry c\. Fisheries d\. Economics e\. Community heath f\. Botany 1. **LESSON 1.3: Theory and Models in the Study of** **Ecology.** **Overview:** From its early days, ecology has been in part a theoretical-- mathematical science, and it is now also a computational science. Mathematical theory arises where systems are relatively simple. In our modern era, computation can address somewhat more complex systems, though creating computations on complex systems that satisfy the basic tenets of science is still problematic. For very complex systems, narrative is all we have available. **Objectives:** **At the end of the lesson the students should be able to:** 1\. determine the role of theory and models in studying Ecology.. 2\. classify the model applied in an ecological study. **Content:** The whole earth begins to be simpler, and at the level of planets and solar systems, things once again become nicely mathematical. This is the level where, with Newton, modern science was born. In part, this emerging simplicity is because levels of detail again merge together. At the level of planetary orbits, it does not matter that dinosaurs once dominated the planet or that Mozart ever wrote any concertos. At larger scales still, solar systems are completely describable with computers, although the mathematics becomes difficult, and as we move out into galaxies and the entire universe the descriptions become difficult again. Changing scales thus involves the successive movement in and out of simplicity. Where is the complexity in the universe greatest? It turns out to be at about one meter. In other words, at our scale. A great spike in complexity appears just where we and other forms of life arose. That is no accident. A philosophical idea called the weak anthropic principle suggests that any part of the universe that can sit around and contemplate itself and the larger universe must itself be complex. We are constrained to live at a scale of great complexity, or not to exist at all. That is worth some reflection. But we try to find simplicity among this complexity, to let us feel we understand, and to let us predict what can happen. **What is a model?** Science strives for simplicity, and models are part of the process. What is a model? It is just a simplified view of something more complex.The word "model" is used here essentially as it's used in everyday English. For example, in ordinary English, "modeling clay" can be used to make simplified miniatures of three-dimensional images of animals, automobiles, buildings, or even full-scale three-dimensional images of objects like the human heart. A "model airplane" can be rendered to show at a glance the physical appearance of a large aircraft, and can even be constructed to fly so as to test aerodynamics under proper rescaling. A "model organism" is a simpler organism that may respond to medical tests or treatments in ways similar to those of a more complex organism. Two different simplifications of time are commonly used in ecological models: - *Discrete time* --- Events happen at periodic time steps, as if time is non-existent in between. - *Continuous time* --- Events happen smoothly and at all times. In addition, there are two different classes of models: - *Macroscale* --- Individual organisms are not tracked, but are measured in aggregate and represented by composite variables such as *N*. - *Microscale* --- Individual organisms are tracked separately. These are also known as agent-based or individual-based models. Macroscale models can be handled either by computers or mathematics, but microscale models are usually restricted to computers. Keep in mind that all four categories are only approximations of reality. Changing scales thus involves the successive movement in and out of simplicity. Where is the complexity in the universe greatest? It turns out to be at about one meter. In other words, at our scale. A great spike in complexity appears just where we and other forms of life arose. That is no accident. A philosophical idea called the weak anthropic principle suggests that any part of the universe that can sit around and contemplate itself and the larger universe must itself be complex. We are constrained to live at a scale of great complexity, or not to exist at all. That is worth some reflection. But we try to find simplicity among this complexity, to let us feel we understand, and to let us predict what can happen. **Research into Ecosystem Dynamics: Ecosystem Experimentation and Modeling** The study of the changes in ecosystem structure caused by changes in the environment (disturbances) or by internal forces is called ecosystem dynamics. Ecosystems are characterized using a variety of research methodologies. Some ecologists study ecosystems using controlled experimental systems, while some study entire ecosystems in their natural state, and others use both approaches. A holistic ecosystem model attempts to quantify the composition, interaction, and dynamics of entire ecosystems; it is the most representative of the ecosystem in its natural state. A food web is an example of a holistic ecosystem model. However, this type of study is limited by time and expense, as well as the fact that it is neither feasible nor ethical to do experiments on large natural ecosystems. To quantify all different species in an ecosystem and the dynamics in their habitat is difficult, especially when studying large habitats such as the Amazon Rainforest, which covers 1.4 billion acres (5.5 million km^2^) of the Earth's surface. For these reasons, scientists study ecosystems under more controlled conditions. Experimental systems usually involve either partitioning a part of a natural ecosystem that can be used for experiments, termed a mesocosm, or by re-creating an ecosystem entirely in an indoor or outdoor laboratory environment, which is referred to as a microcosm. A major limitation to these approaches is that removing individual organisms from their natural ecosystem or altering a natural ecosystem through partitioning may change the dynamics of the ecosystem. These changes are often due to differences in species numbers and diversity and also to environment alterations caused by partitioning (mesocosm) or re-creating (microcosm) the natural habitat. Thus, these types of experiments are not totally predictive of changes that would occur in the ecosystem from which they were gathered. As both of these approaches have their limitations, some ecologists suggest that results from these experimental systems should be used only in conjunction with holistic ecosystem studies to obtain the most representative data about ecosystem structure, function, and dynamics. Scientists use the data generated by these experimental studies to develop ecosystem models that demonstrate the structure and dynamics of ecosystems. Three basic types of ecosystem modeling are routinely used in research and ecosystem management: a conceptual model, an analytical model, and a simulation model. A conceptual model is an ecosystem model that consists of flow charts to show interactions of different compartments of the living and nonliving components of the ecosystem. A conceptual model describes ecosystem structure and dynamics and shows how environmental disturbances affect the ecosystem; however, its ability to predict the effects of these disturbances is limited. Analytical and simulation models, in contrast, are mathematical methods of describing ecosystems that are indeed capable of predicting the effects of potential environmental changes without direct experimentation, although with some limitations as to accuracy. An analytical model is an ecosystem model that is created using simple mathematical formulas to predict the effects of environmental disturbances on ecosystem structure and dynamics. A simulation model is an ecosystem model that is created using complex computer algorithms to holistically model ecosystems and to predict the effects of environmental disturbances on ecosystem structure and dynamics. Ideally, these models are accurate enough to determine which components of the ecosystem are particularly sensitive to disturbances, and they can serve as a guide to ecosystem managers (such as conservation ecologists or fisheries biologists) in the practical maintenance of ecosystem health. **Conceptual Models** Conceptual models are useful for describing ecosystem structure and dynamics and for demonstrating the relationships between different organisms in a community and their environment. Conceptual models are usually depicted graphically as flow charts. The organisms and their resources are grouped into specific compartments with arrows showing the relationship and transfer of energy or nutrients between them. Thus, these diagrams are sometimes called compartment models. To model the cycling of mineral nutrients, organic and inorganic nutrients are subdivided into those that are bioavailable (ready to be incorporated into biological macromolecules) and those that are not. For example, in a terrestrial ecosystem near a deposit of coal, carbon will be available to the plants of this ecosystem as carbon dioxide gas in a short-term period, not from the carbon-rich coal itself. However, over a longer period, microorganisms capable of digesting coal will incorporate its carbon or release it as natural gas (methane, CH~4~), changing this unavailable organic source into an available one. This conversion is greatly accelerated by the combustion of fossil fuels by humans, which releases large amounts of carbon dioxide into the atmosphere. This is thought to be a major factor in the rise of the atmospheric carbon dioxide levels in the industrial age. The carbon dioxide released from burning fossil fuels is produced faster than photosynthetic organisms can use it. This process is intensified by the reduction of photosynthetic trees because of worldwide deforestation. Most scientists agree that high atmospheric carbon dioxide is a major cause of global climate change. Conceptual models are also used to show the flow of energy through particular ecosystems. Figure 1.3.1 is based on Howard T. Odum's classical study of the Silver Springs, Florida, holistic ecosystem in the mid-twentieth century.^2^ This study shows the energy content and transfer between various ecosystem compartments. Figure 1.3.1: This conceptual model shows the flow of energy through a spring ecosystem in Silver Springs, Florida. Notice that the energy decreases with each increase in trophic level. Why do you think the value for gross productivity of the primary producers is the same as the value for total heat and respiration (20,810 kcal/m2/yr)? **Analytical and Simulation Models** The major limitation of conceptual models is their inability to predict the consequences of changes in ecosystem species and/or environment. Ecosystems are dynamic entities and subject to a variety of abiotic and biotic disturbances caused by natural forces and/or human activity. Ecosystems altered from their initial equilibrium state can often recover from such disturbances and return to a state of equilibrium. As most ecosystems are subject to periodic disturbances and are often in a state of change, they are usually either moving toward or away from their equilibrium state. There are many of these equilibrium states among the various components of an ecosystem, which affects the ecosystem overall. Furthermore, as humans have the ability to greatly and rapidly alter the species content and habitat of an ecosystem, the need for predictive models that enable understanding of how ecosystems respond to these changes becomes more crucial. Analytical models often use simple, linear components of ecosystems, such as food chains, and are known to be complex mathematically; therefore, they require a significant amount of mathematical knowledge and expertise. Although analytical models have great potential, their simplification of complex ecosystems is thought to limit their accuracy. Simulation models that use computer programs are better able to deal with the complexities of ecosystem structure. A recent development in simulation modeling uses supercomputers to create and run individual-based simulations, which accounts for the behavior of individual organisms and their effects on the ecosystem as a whole. These simulations are considered to be the most accurate and predictive of the complex responses of ecosystems to disturbances. **Summary** Ecosystems exist on land, at sea, in the air, and underground. Different ways of modeling ecosystems are necessary to understand how environmental disturbances will affect ecosystem structure and dynamics. Conceptual models are useful to show the general relationships between organisms and the flow of materials or energy between them. Analytical models are used to describe linear food chains, and simulation models work best with holistic food webs. **Enrichment:** 1\. Why do you think the value for gross productivity of the primary producers is the same as the value for total heat and respiration (20,810 kcal/m^2^/yr)? 2.According to the first law of thermodynamics, energy can neither be created nor destroyed. Eventually, all energy consumed by living systems is lost as heat or used for respiration, and the total energy output of the system must equal the energy that went into it. **Review Questions** The ability of an ecosystem to return to its equilibrium state after an environmental disturbance is called \_\_\_\_\_\_\_\_. 1. resistance 2. restoration 3. reformation 4. resilience A re-created ecosystem in a laboratory environment is known as a \_\_\_\_\_\_\_\_. 1. mesocosm 2. simulation 3. microcosm 4. reproduction Decomposers are associated with which class of food web? 1. grazing 2. detrital 3. inverted 4. aquatic The primary producers in an ocean grazing food web are usually \_\_\_\_\_\_\_\_. 1. plants 2. animals 3. fungi 4. phytoplankton What term describes the use of mathematical equations in the modeling of linear aspects of ecosystems? 1. analytical modeling 2. simulation modeling 3. conceptual modeling 4. individual-based modeling The position of an organism along a food chain is known as its \_\_\_\_\_\_\_\_. 1. locus 2. location 3. trophic level 4. microcosm **C. Assignment** 1.Compare and contrast food chains and food webs. What are the strengths of each concept in describing ecosystems? 2.Describe freshwater, ocean, and terrestrial ecosystems. 3..Compare grazing and detrital food webs. Why would they both be present in the same ecosystem? **\ ** **LESSON 1.4: The Scientific Methods** **Overview:** The practice of scientific method by most scientists would indeed be considered a success by almost any measure. Science "as a way of knowing" the world around us constantly tests, confirms, rejects and ultimately reveals new knowledge, integrating that knowledge into our worldview. **Objectives:** **At the end of the lesson, the students should be able to:** 1\. identify the components of the scientific method 2\. compare and contrast laws and theories and place them and other elements of the scientific enterprise into their place in the cycle of the scientific method. **Content:** Scientists search for answers to questions and solutions to problems by using a procedure called the scientific method. This procedure consists of making observations, formulating hypotheses, and designing experiments, which in turn lead to additional observations, hypotheses, and experiments in repeated cycles (Figure 1.4.1) Figure 1.4.1: The Steps in the Scientific Method. **Step 1: Make observations** Observations can be qualitative or quantitative. **Qualitative observations** describe properties or occurrences in ways that do not rely on numbers. Examples of qualitative observations include the following: the outside air temperature is cooler during the winter season, table salt is a crystalline solid, sulfur crystals are yellow, and dissolving a penny in dilute nitric acid forms a blue solution and a brown gas. **Quantitative observations** are measurements, which by definition consist of both a number and a unit. Examples of quantitative observations include the following: the melting point of crystalline sulfur is 115.21° Celsius, and 35.9 grams of table salt---whose chemical name is sodium chloride---dissolve in 100 grams of water at 20° Celsius. For the question of the dinosaurs' extinction, the initial observation was quantitative: iridium concentrations in sediments dating to 66 million years ago were 20--160 times higher than normal. **Step 2: Formulate a hypothesis** After deciding to learn more about an observation or a set of observations, scientists generally begin an investigation by forming a hypothesis, a tentative explanation for the observation(s). The hypothesis may not be correct, but it puts the scientist's understanding of the system being studied into a form that can be tested. For example, the observation that we experience alternating periods of light and darkness corresponding to observed movements of the sun, moon, clouds, and shadows is consistent with either of two hypotheses: a. Earth rotates on its axis every 24 hours, alternately exposing one side to the sun, or b. the sun revolves around Earth every 24 hours. Suitable experiments can be designed to choose between these two alternatives. For the disappearance of the dinosaurs, the hypothesis was that the impact of a large extraterrestrial object caused their extinction. Unfortunately (or perhaps fortunately), this hypothesis does not lend itself to direct testing by any obvious experiment, but scientists can collect additional data that either support or refute it. **Step 3: Design and perform experiments** After a hypothesis has been formed, scientists conduct experiments to test its validity. Experiments are systematic observations or measurements, preferably made under controlled conditions---that is, under conditions in which a single variable changes. **Step 4: Accept or modify the hypothesis** A properly designed and executed experiment enables a scientist to determine whether the original hypothesis is valid. In which case he can proceed to step 5. In other cases, experiments often demonstrate that the hypothesis is incorrect or that it must be modified thus requiring further experimentation. **Step 5: Development into a law and/or theory** More experimental data are then collected and analyzed, at which point a scientist may begin to think that the results are sufficiently reproducible (i.e., dependable) to merit being summarized in a law, a verbal or mathematical description of a phenomenon that allows for general predictions. A law simply says what happens; it does not address the question of why. A theory attempts to explain why nature behaves as it does. Laws are unlikely to change greatly over time unless a major experimental error is discovered. In contrast, a theory, by definition, is incomplete and imperfect, evolving with time to explain new facts as they are discovered. Because scientists can enter the cycle shown in Figure 1.4.11.4.1 at any point, the actual application of the scientific method to different topics can take many different forms.  For example, a scientist may start with a hypothesis formed by reading about work done by others in the field, rather than by making direct observations.. **Summary** The scientific method is a method of investigation involving experimentation and observation to acquire new knowledge, solve problems, and answer questions. The key steps in the scientific method include the following: - Step 1: Make observations. - Step 2: Formulate a hypothesis. - Step 3: Test the hypothesis through experimentation. - Step 4: Accept or modify the hypothesis. - Step 5: Development into a law and/or a theory **Enrichment:** 1.Classify each statement as a law, a theory, an experiment, a hypothesis, an observation. a. Ice always floats on liquid water. b. Birds evolved from dinosaurs. c. Hot air is less dense than cold air, probably because the components of hot air are moving more rapidly. d. When 10 g of ice were added to 100 mL of water at 25°C, the temperature of the water decreased to 15.5°C after the ice melted. e. The ingredients of Ivory soap were analyzed to see whether it really is 99.44% pure, as advertised. 11.Classify each statement as a law, a theory, an experiment, a hypothesis, a qualitative observation, or a quantitative observation. a. Measured amounts of acid were added to a Rolaids tablet to see whether it really "consumes 47 times its weight in excess stomach acid." b. Heat always flows from hot objects to cooler ones, not in the opposite direction. c. The universe was formed by a massive explosion that propelled matter into a vacuum. d. Michael Jordan is the greatest pure shooter ever to play professional basketball. e. Limestone is relatively insoluble in water but dissolves readily in dilute acid with the evolution of a gas. **Lesson 1.5 Basic Ideas in Ecology** **Overview:** **Objectives:** At the end of the lesson, the students should be able to: 1.define and comprehend the basic ideas in ecology. 2\. differentiate ecosystem, niche and habitat. 3\. describe the interaction of ecosystem components. 4\. explain the levels of ecological hierarchy. **CONTENT** **Living Things and the Environment** Despite their tremendous diversity, all organisms have the same basic needs: energy and matter. These must be obtained from the environment. Therefore, organisms are not closed systems. They depend on and are influenced by their environment. Figure 1.5.1: An important role of ecology is identifying, and forging plans to protect, endangered species, like the Madagascar lemur pictured here. Ecological assessments have determined that of all the world\'s endangered animals, Madagascar's lemurs are among the species that are closest to extinction. Knowledge such as this is a necessary first step in preventing the extinction of these primates. (CC BY-SA 2.0; Frank Vassen via [[Wikimedia.org]](https://commons.wikimedia.org/wiki/File:Milne-Edwards%27_Sportive_Lemur,_Ankarafantsika,_Madagascar.jpg)). The environment of an organism includes two types of factors: **biotic **and **abiotic**. - Biotic factors are the living aspects of the environment. They consist of other organisms, including members of the same and different species. - Abiotic factors are the nonliving aspects of the environment. They include factors such as sunlight, soil, temperature, and water. Consider as an example the relationship between leafhoppers and ants. Ants "herd" leafhoppers and use their excretions for food, much as a dairy farmer herds cows and use their milk. Leafhoppers suck sap from plants and excrete excess liquid as a sugary fluid called honeydew. As the honeydew passes out of a leafhopper's anus, the ant "farmer" feeds on the fluid.  Figure 1.5.2: The ant and leafhopper in this photo have a mutually beneficial relationship. Where they are most likely to interact is influenced by the amount of available shade. (CC BY-NC; fir0002 Fir0002/Flagstaffotos via [[Wikimedia.org]](https://commons.wikimedia.org/wiki/File:Common_jassid_nymph_and_ant.jpg)). The leafhoppers in the "herd" also benefit from their relationship with the "farmer." The ant protects the leafhoppers from potential predators such as wasps. The amount of shade in the environment, which is an abiotic factor, is an important influence on the leafhoppers and ants. Environments with at least 50 percent shade are more densely populated by ants and leafhoppers than sunnier environments. Some species of "herder" ants even construct shelters to provide shade for their "herds." **Ecological Hierarchy** Studying all living things and their environments would be a huge undertaking. Generally, the study of ecology is made more manageable by organizing the biological world into a nested hierarchy. Below the level of the individual organism, the hierarchy ranges from genes to cells, to tissues, to organs, to organ systems. These levels of the hierarchy are typically the focus of biology, genetics, physiology, and similar sciences. Figure 1.5.3: This figure shows levels of organization in nature, from the individual organism to the biosphere. Many individuals make up a population. Many populations make up a community. A community and its environment make up the ecosystem. Ecosystems are part of a biome. All the biomes on earth make up the biosphere. (CC BY-NC 3.0; Christopher Auyeung of [[CK-12 Foundation]](https://www.ck12.org/book/ck-12-college-human-biology/section/24.2/)). Ecology typically focuses on the living world at and above the level of the individual organism. These levels are illustrated in Figure 1.5.3 and defined as follows: - A **population** consists of all the individual organisms of the same species that live and interact in the same area. For example, all of the angelfish living in the same area of the ocean make up the angelfish population. - A **community **refers to all of the populations of different species that live and interact in the same area. The aquatic community that includes the angelfish also includes the populations of other species of fish, corals, and many other organisms. - An **ecosystem **includes all the living things in a given area, together with the nonliving environment. The nonliving environment includes abiotic factors such as water, minerals, and sunlight. - A **biome **is a group of similar ecosystems with the same general type of physical environment anywhere in the world. Terrestrial biomes are generally delineated by climate and major types of vegetation. Examples of terrestrial biomes include tropical rainforests and deserts. Aquatic biomes are generally defined by the distance from shore and depth of water. Examples of aquatic biomes include the shallow water near shore (littoral zone) and the deepest water at the bottom of a body of water (benthic zone). - The **biosphere** includes every part of Earth where life exists, including all the land, water, and air where living things can be found. The biosphere is the largest ecological category and consists of many different biomes. **Ecosystem** The ecosystem is one of the most important concepts in ecology and often the focus of ecological studies. It consists of all the biotic and abiotic factors in an area and their interactions. While an ecosystem is a real system in nature, it is often artificially delineated by researchers. For example, depending on an ecologist's research focus, a lake could be considered an ecosystem, but so could a dead log, like the one in Figure 1.5.3. Both the lake and the log contain a variety of species that interact with each other and with abiotic factors. Figure 1.5.4: Dead logs like this one are called "nurse logs" because they provide a suitable site for the growth of mosses, small plants, and many other kinds of organisms. The organisms that live in and on the log are part of the same ecosystem. (CC BY 2.0 Generic; via flickr.com; [[Nicholas A. Tonelli]](https://www.flickr.com/people/14922165@N00) ). When it comes to energy, ecosystems are not closed. They need constant inputs of energy. Most ecosystems get energy from sunlight. A small minority, including hydrothermal vent ecosystems, get energy from chemical compounds. Unlike energy, the matter is not constantly added to ecosystems. Instead, it is recycled. Water and elements such as carbon and nitrogen are used over and over again. **Niche** One of the most important concepts associated with ecosystems is the niche. A **niche** refers to the role of a species in its ecosystem. It includes all the ways that the species interacts with the biotic and abiotic factors of the ecosystem. Two important aspects of any species' niche are its sources of energy and nutrients and how it obtains them. For example, the jumping spider in the photo below is a carnivore (meat eater) that obtains food by preying on insects such as flies. Figure 1.5.5: This jumping spider has captured and is consuming a long-legged green fly. What the spider eats and how it obtains it are important aspects of its ecological niche. (CC BY 2.0 Generic; [[James Niland]](https://www.flickr.com/people/25027666@N02)). Habitat Another fundamental aspect of a species' niche is its habitat. The **habitat** is the natural environment in which a species lives and to which it is adapted. A species' habitat includes any factors of the environment --- including both biotic and abiotic factors --- that are related directly or indirectly to the use of the environment by the species. Figure 1.5.6: *Pieris rapae *butterflies have general habitat requirements, so they can live in many different ecosystems. (CC BY 2.0 Generic; Christian Bauer; via [[Wikimedia.org]](https://commons.wikimedia.org/wiki/File:ChristianBauer_Pieris_rapae_adult.jpg)) Species may have general or specific habitat requirements. For example, small white butterflies in the species *Pieris rapae*  are found on all continents of the world except Antarctica. Their larvae can feed on many different plant species, and the butterflies themselves thrive in any open location. In contrast, large blue butterflies in the species *Phengaris arion* (Figure 24.2.824.2.8) are found only in certain types of grassland areas. Their larvae can feed only on species in the plant genus *Thymus.* In addition, because of their complex life cycle, the butterflies can live only in areas in which certain ant species also reside. Figure 1.5.7:* Phengaris arion* butterflies have very specific habitat requirements, so they can live only in a limited number of ecosystems. (CC BY 2.0 Generic; via flickr.com [[Pengannel]](https://www.flickr.com/people/25801055@N00)). **Summary** - Ecology is the study of how living things interact with each other and with their environment. All organisms need energy and matter that must be obtained from the environment, so organisms are not closed systems. The environment of an organism includes biotic factors, which are the living aspects of the environment, and abiotic factors, which are the nonliving aspects of the environment. - Ecologists generally organize the biological world in a nested hierarchy. Above the level of the individual organism, from the least to most inclusive, the levels of this hierarchy are the population, community, ecosystem, biome, and biosphere. The biosphere consists of every part of Earth where life exists, including the land, water, and air. **Enrichment: ( maximum of 3 pages only)** 1. Define ecology. 2. Why are individual organisms not closed systems? 3. Compare and contrast biotic and abiotic environmental factors, and give examples of each type of factor. 4. Describe the nested hierarchy by which ecologists organize the biological world. 5. What is the biosphere? 6. Define ecosystem. 7. Describe the niche concept in ecology. 8. How is the habitat of a species defined? 9. State the competitive exclusion principle. 10. Compare and contrast the roles of energy and matter in an ecosystem. 11. Which of the following can contain more than one species for an extended period of time? Explain your answer. 12. Do you think there can be an ecosystem in an urban environment, such as a city? Why or why not? 13. *True or False.* The jumping spider and its prey occupy the same niche. 14. *True or False. *The same type of biome can exist in different locations on the plane. Chapman JL. And MJ Reiss, 2010. Ecology;Principles and Application.2^nd^ Ed. Cambridge University Presss Campbell NA. et al 2011. Biology.9^th^ ed. Pearson Education South Asia Pte Ltd. Singapore Miller Jr. GT and SE Spoolman. 2009. Essentials of Ecology.5^th^ Cengage Learning. Connie Rye (East Mississippi Community College), Robert Wise (University of Wisconsin, Oshkosh), Vladimir Jurukovski (Suffolk County Community College), Jean DeSaix (University of North Carolina at Chapel Hill), Jung Choi (Georgia Institute of Technology), Yael Avissar (Rhode Island College) among other contributing authors. **Note: Please always observe the General Instructions** 1. **In essay, answer it direct to the point but still concise and complete.** 2. **Send your answer in document at my gmail (adfrancisco628\@gmail.com)** 3. **Observe the submission date and the maximum number of pages.**