Environmental Science Introduction | Past Paper PDF

ENVIRONMENTAL SCIENCE In today’s world, human activities have led to severe INTRODUCTION environmental issues such as climate change, habitat destruction, and loss of biodiv...

ENVIRONMENTAL SCIENCE In today’s world, human activities have led to severe INTRODUCTION environmental issues such as climate change, habitat destruction, and loss of biodiversity. Environmental science - study of the multitude interactions between humans and the world around ES provides the scientific basis for decision- them, living and non-living. making and developing policies that address these problems and protect the environment. As the world develops and human population continues to grow, as technology advances and It also includes knowledge of the connection human needs and wants increase - human between human health and the environment. population’s impacts on the world’s environment become widespread. Environmental science research and sustainable teaching are necessary to balance our ecosystems, Environmental impacts have corresponding effects undoing past harm and averting future damage. on human health and well-being. (Bueno) Environmental Science uses scientific approaches to understand the complex systems in our habitats. A few of the major challenges that are the topics of It systematically studies our environment and our environmental science include: role and place in developing and changing it. (Cunningham & Cunningham) 1. Global Climate Change: Refers to long- term shifts in temperatures and weather patterns, Environmental science integrates multiple primarily driven by human activities such as burning disciplines, including biology, chemistry, physics, fossil fuels. Consequences include rising sea levels, and earth science, to understand the relationship extreme weather events, and disruptions to between human activity and the environment. Some ecosystems. recent events include climate change, air pollution, 2. Management of Earth’s Water Resources: water pollution, and habitat destruction. Involves ensuring the sustainable use and quality of freshwater supplies. Issues include over-extraction, Environmental science applies basic knowledge to pollution, and the impacts of climate change on water real-world problems: an environmental scientist availability. might study patterns of biodiversity or river system 3. Energy and Mineral Resource Depletion: dynamics for their own sake. Refers to the exhaustion of non-renewable resources due to overconsumption and unsustainable practices. An environmental scientist might also study these This raises concerns about energy security and the systems with the larger aim of saving species. need for alternative, renewable sources. 4. Meeting the Food, Fiber, and Clothing Needs: As the global population grows, there is increasing pressure to produce enough food and Why Is the Study of the Environment Important? materials sustainably, while addressing issues like land degradation and water scarcity. Environmental science primarily helps us 5. Air Pollution and Acid Rain Deposition: understand how human activities impact the Air pollutants from industrial activities and vehicles environment. can lead to health problems and environmental damage. Acid rain results from sulfur and nitrogen In the process of understanding them, ES provides compounds in the atmosphere, affecting soil and solutions to the ecological problems that threaten our water bodies. planet. 6. Stratospheric Ozone Depletion: The thinning of the ozone layer, mainly caused by chlorofluorocarbons (CFCs), increases UV radiation reaching the Earth, leading to health risks like skin cancer and environmental impacts.  7. Water Pollution: Contamination of water Ecological Science: Focuses on ecosystems bodies from industrial waste, agricultural runoff, and and interactions between organisms and their sewage affects drinking water quality and aquatic environment. ecosystems, posing health risks to humans and Climate Science: Studies Earth’s climate and wildlife. strategies to mitigate human impacts. 8. Soil Erosion, Fertility Depletion, and Environmental Chemistry: Examines Contamination: Unsustainable agricultural chemical processes in the environment, practices and deforestation can lead to loss of topsoil, addressing pollution and prevention reduced fertility, and contamination from pesticides techniques. and heavy metals, impacting food production. Soil Science: Investigates soil composition, 9. Deforestation: The clearing of forests for structure, and function within ecosystems. agriculture, logging, or urban development results in Environmental Economics: Analyzes the loss of biodiversity, disruption of carbon cycles, and economic impacts of environmental issues contributes to climate change. and potential solutions. 10. Habitat Destruction on Land and in the Oceans: Human activities such as urbanization, Careers in Environmental Science mining, and fishing destroy natural habitats, leading to biodiversity loss and threatening species survival. A degree in environmental science opens various 11. Spread of Infectious Diseases: career opportunities, including: Environmental changes, such as deforestation and climate change, can alter ecosystems, allowing Environmental Scientist: Researches diseases to spread and increase the prevalence of environmental issues and develops solutions. antibiotic-resistant organisms. Environmental Engineer: Designs solutions 12. Long-Term Sustainability of Global and for problems like air and water pollution. National Economies: Balancing economic growth Wildlife Biologist: Studies wildlife and their with environmental protection is crucial for ensuring habitats, working to protect endangered resources are available for future generations and species. minimizing ecological damage. Environmental Consultant: Advises businesses and organizations on environmental issues. Environmental Educator: Promotes History of Environmental Science awareness and educates the public on climate and environmental issues. Environmental science has a rich history beginning in the mid-1800s, when scientists started studying living organisms and ecological factors. Initially, the focus was on discovering new species and Some Pioneering Scientists Who Influenced the understanding natural processes to improve human Study of Environmental Science life, such as identifying new food sources or valuable materials. In the late 19th and early 20th centuries, THOMAS ROBERT MALTHUS key figures like Charles Darwin, Thomas Huxley, 1887-1948 and John Muir explored the relationship between the environment and human activities. As awareness English economist and demographer of environmental issues grew, environmental science Author of the book “An Essay on the Principle of emerged as a distinct field, emphasizing a Population” comprehensive and interdisciplinary approach to Predicted the exponential population growth studying these challenges. would outpace linear food production, which would lead to starvation. Subdisciplines of Environmental Science Malthusianism: This means that population growth will always tend to outrun the food supply and that Environmental science encompasses several the betterment of humankind is impossible without important subdisciplines: stern limits on reproduction.  based on the probability of their extinction. The list is maintained by scientists from around the world. ALDO LEOPOLD 1887-1948 Born in Burlington, Iowa 1990 Father of wildlife conservation in the US Earth Day goes global (April 22, 1990) Author of A Sand County Almanac Earth Day becomes an international celebration of Known for his “concept of the land ethic”: humanity's environmental successes and an “We abuse the land because we regard it as a important motivator in the continued fight for the commodity belonging to us. When we see land as a planet's health. community to which we belong, we may begin to use it with love and respect.” 1992 UN Earth Summit (June 3-14, 1992) RACHEL CARSON The Earth Summit is the largest gathering of world 1907-1964 leaders at the time and seeks to foster economic development in ways that will protect the Mother of the Environmental Science Movement environment. She wrote about the dangers of pesticides such as DDT in her book “Silent Spring” (1962), highlighting the risks of its use in agriculture. She was attacked by pesticide companies and the 1992 chemical industry, discrediting her work and Biodiversity Treaty (June 5, 1992) threatening lawsuits. One of the treaties signed at the UN Earth Summit, Carson died before she could see any substantive the Convention on Biological Diversity aims to results from her work, but she left behind some of the promote the conservation of biodiversity and the most influential environmental writing ever equitable sharing of the planet's genetic resources. published. DDT was banned as a result of her study. 1997 TIMELINE OF KEY EVENTS IN Kyoto Protocol (December 11, 1997) ENVIRONMENTAL SCIENCE The groundbreaking Kyoto Protocol is one of the first international treaties aimed at addressing 1962 global warming and reducing greenhouse gas Silent Spring published (September 1962) emissions. Rachel Carson's prophetic book is credited with creating a worldwide awareness of the dangers of environmental pollution and the risks of pesticides. It is one of the most influential books in 2015 the modern environmental movement. Paris Agreement (December 12, 2015) The Paris Agreement is adopted at the 21st Conference of the Parties to the UN Framework Convention on Climate Change. It replaces the 1964 Kyoto Protocol to curb the release of greenhouse IUCN Red List (1964) gases and is eventually signed by 195 countries. The IUCN Red List of Threatened Species is created to objectively assess and classify species SEVEN ENVIRONMENTAL PRINCIPLES IN WAR DESTROYS WILDLIFE AND ENVIRONMENTAL SCIENCES HABITATS. Adapted from Barry Commoner, as compiled by Miriam College. 2. ALL FORMS OF LIFE ARE IMPORTANT - 1. EVERYTHING IS CONNECTED TO ANG LAHAT NA MAY BUHAY IBA IBANG EVERYTHING ELSE - ANG LAHAT NG KAPALIGIRAN SA DAIGDIG AY BAGAY SA KAPALIGIRAN NG MUNDO AY MAHALAGA MAGKAKAUGNAY Each organism plays a fundamental role in nature. This principle is best exemplified by the concept of The role is occupational or functional position, ecosystem. In an ecosystem, all biotic and abiotic otherwise known as NICHE. The niche cannot be components interact with each other to ensure that simultaneously occupied by more than one species. the system is perpetuated. Any outside interference may result in an imbalance and the deterioration of It is apparent that all living things must be the system. considered invaluable in the maintenance of homeostasis in the environment. It is easy to The intricate relationship of various elements of the appreciate the beautiful butterflies, especially ecosystem binds the components together into one knowing their important role in pollination. functional unit. It has been customary for many to step on wriggling THERE IS A CAUSE-AND-EFFECT CHAIN, creatures (e.g., earthworms) or react adversely to EVEN WHEN IT IS NEITHER ALWAYS snakes. Spiders are often looked at with disdain. VISIBLE NOR OBSERVABLE Each of the species plays an important role in the functioning of the ecosystem. The ecosystem has living or biotic components and abiotic factors such as the soil, air, and water. The THE VARIETY OF LIFE FORMS forest ecosystem is an example of a functional unit. CONTRIBUTES TO THE STABILITY OF The abiotic environment provides the basic THE ENVIRONMENT. elements (nitrogen, hydrogen, oxygen, and other ALL LIVING ORGANISMS WERE CREATED minerals) needed for the growth of plants and food FOR A PURPOSE, EITHER TO HUMANS, TO production for animals. OTHER SPECIES, OR TO THE GLOBAL ECOSYSTEM. Plants provide oxygen for animal consumption. The soils are the home of worms and other ground or The Philippines ranks high among the surface animals. The shrubs and trees offer habitats biodiversity hotspots, being the richest yet for birds, snakes, and wild pigs. The leaves and most threatened of terrestrial ecosystems fruits serve as food for all living components of the globally. forest ecosystem. The composition of biological diversity changes slowly, but the rate of transition has Animal wastes and decomposing leaves serve as accelerated due to factors like habitat soil nutrients that plant and tree roots absorb for destruction. growth. Human interaction with nature changes the Deforestation diminishes species, such as ecosystems. Wastes improperly disposed of birds, and impacts ecosystems— deteriorate water and soil quality. deforestation in mountains can cause floods, drought, and erosion in lowlands. SUSPENDED PARTICULATES FROM Pollution of water affects aquatic life, and VEHICLES MAY CAUSE RESPIRATORY over-harvesting leads to unsustainable use PROBLEMS FOR CITY RESIDENTS. of resources.  Cities can preserve patches of forests and trees and support the captive breeding of endangered species. 5. NATURE KNOWS BEST - ANG Local actions, like overfishing, can have KALIKASAN AY MAS NAKAKAALAM broader impacts on regional ecosystems. This principle emphasizes adhering to natural processes to ensure a steady supply of resources. 3. EVERYTHING MUST GO SOMEWHERE - Nutrient cycling is crucial; disruptions can ANG LAHAT NG BAGAY AY MAY lead to ecological imbalances. PATUTUNGUHAN Burning organic waste can release harmful carbon dioxide, contributing to the This principle states that nothing can be greenhouse effect. created or destroyed, only transformed or Natural mechanisms maintain homeostasis transferred. in ecosystems, controlling population When waste is disposed of, it does not dynamics through predator-prey disappear; it goes to landfills or the ocean, relationships. affecting the environment. Human interventions can lead to ecological Burning materials, like wood, creates smoke backlash, such as floods and invasive and ash, which also have environmental species. consequences. If the ecosystem is in a state of equilibrium, By-products of consumption return to the then human intervention takes place, environment, and ecosystems rely on negative impacts may arise nutrient cycling. Food chains and food webs Artificial products such as plastic are non- Population control through predator-prey biodegradable, necessitating retrieval, relationships collection, and recycling. Flow of energy Biodegradable wastes can be composted, o Light energy to chemical energy while solid wastes should be reduced, o Producers eaten by consumers segregated, reused, and recycled. 6. NATURE IS BEAUTIFUL AND WE ARE 4. OURS IS A FINITE EARTH - ANG MUNDO STEWARDS OF GOD’S CREATION - ANG AY MAY MGA LIMITASYON KALIKASAN AY MAGANDA AT TAYO ANG TAGAPANGASIWA Earth's resources are either renewable (e.g., water, air, plants) or non-renewable (e.g., Humans, made in God’s image, have a duty fossil fuels, metals). to care for creation, not to abuse it. Renewable resources can be replenished, but This stewardship is rooted in many religious pollution can make them inaccessible. beliefs, emphasizing respect for all life. Awareness of resource limits is vital for Stewardship signifies guardianship over developing sustainable consumption nature, acknowledging that humans are part patterns. of the ecosystem. Excessive extraction of non-renewable Teachings across cultures advocate for a resources poses significant risks to kinship with nature, reinforcing our sustainability. responsibility to protect it. Population growth increases demand for Sacrament resources, highlighting the importance of o Nature is a testimony of God’s love. reducing consumption, using renewable Covenant energy, and implementing pollution o Protection of the earth is a life control. mission.  Stewardship o We are not owners but guardians of the integrity of nature. Kinship o We are no higher than the birds and fishes. “Brother Sun, Sister Moon.” 7. EVERYTHING CHANGES - ANG LAHAT AY NAGBABAGO It is said that the only permanent thing is change. Change may be cyclical, linear or random. Cyclical o Evolution of species Linear o Seasonal changes Random o Eruption of Mt. Pinatubo Human-induced changes, such as climate change, can have profound and rapid effects on ecosystems. Changes in the biophysical world occur naturally o Metamorphosis o Seasons o Random changes Sustainable development practices are essential to mitigate negative impacts and encourage positive environmental changes.  MEANING AND COMPONENTS OF Species ECOSYSTEMS They are genetically alike. Ecosystem They are capable of freely interbreeding and producing fertile offspring. It is all of the living organisms (plants, animals, and bacteria) and the nonliving components (air, water, Trophic Structure of an Ecosystem soil, weather) that interact with each other as a system. Essentially, it’s an ecological system. 1. Autotrophic Component: Producers 2. Heterotrophic Component: Consumers “No life exists in a vacuum. For survival, anything requires from its environment a supply of energy, a Abiotical Factors supply of materials, and a removal of waste products.” They are physical, or nonliving, elements that shape the ecosystem. Key climatic conditions in Ecology terrestrial, freshwater, and marine ecosystems include: Derived from the Greek root “oikos” meaning “house” and “logy” meaning “the science of” or “the Temperature study of.” Precipitation and humidity Wind It is the study of the earth’s households, including Nutrients available plants, animals, microorganisms, and people that Substrate (soil) live together as interdependent components. It Atmospheric gases focuses on organisms, as well as energy flows and Currents material cycles in land, sea, air, and freshwater. Sunlight It is the “study of the structure and function of Other Physical Factors nature.” It can be defined as the “totality or pattern of relations between organisms and their Light environment.” Under natural conditions in the field, Fire this pattern is complex and non-linear. Therefore, Pressure ecology is the study of an organism's interaction Geomagnetism with its environment. Abiotic Factors and Their Influence Biocentrism: A belief that humans are part of nature. Abiotic factors determine the type of organisms that Anthropocentrism: A belief that humans are can successfully live in a particular area: not a part of nature. Sunlight: Necessary for photosynthesis. Ernst Haeckel Water: All living things require some water, though some can survive with lesser A German zoologist and evolutionist who amounts. defined a new science, “Oecologie.” Temperature: Each species has a range of He suggested that it was important to study temperatures in which it can survive; living organisms and their interaction with exceeding these limits makes survival the non-living world. difficult. Oxygen: Many organisms require oxygen for cellular respiration to obtain energy from food, while some bacteria are harmed by its presence.  Soil: Factors like soil type, pH, water Victor Shelford later explained Liebig’s principle: retention, and available nutrients determine which organisms can thrive. For example, Each environmental factor has both cacti live in sandy soil, while cattails thrive minimum and maximum levels, known as in water-saturated soil. tolerance limits, beyond which a species cannot survive or reproduce. Limiting Factors These limits determine where a particular organism can live. An organism’s physiology and behavior allow it to In some species, tolerance limits affect the survive only in certain environments. Temperature, distribution of young differently than that of moisture level, nutrient supply, soil and water adults. chemistry, living space, and other environmental factors must be at appropriate levels for organisms to Desert Pupfish persist. Adult pupfish can survive temperatures A critical limiting factor prevents an organism from between 0°C and 42°C. expanding everywhere. They can tolerate a wide range of salt concentrations. Limitations Can Include: Lichens and eastern white pine, for Physiological stress (due to inappropriate example, are highly sensitive to sulfur levels of a critical environmental factor) dioxide and ozone, respectively. o Moisture o Light Indicator species: A general term for organisms o Temperature whose sensitivities can provide insights about o pH environmental conditions in an area. o Specific nutrients Competition (with other species) Example: Anglers know that trout require Predation (including parasitism and disease) cool, clean, well-oxygenated water. The presence or absence of trout is used as an Justus von Liebig (1840) indicator of water quality. The single factor in shortest supply relative to Habitat demand is the critical factor determining where a species lives. A habitat describes the place or set of environmental conditions in which a particular organism lives Example: Giant Saguaro Cactus (Carnegiea (Cunningham & Cunningham). It can be defined as gigantea) the natural abode of an animal, plant, or person (Singh). Grows in the dry, hot Sonoran Desert of Southern Arizona and Northern Mexico. Aquatic Habitats Tolerant of: o Extreme heat Marine o Drought Brackish o Intense sunlight Freshwater o Nutrient-poor soil Extremely sensitive to freezing Terrestrial Habitats temperatures. Land supports numerous terrestrial Ecologist Victor Shelford (1877-1968) organisms.  Soil provides a habitat for a variety of Example: Black Bear (Ursus americana) microbes, plants, and animals. Omnivorous and abundant. Biomes Ranges across most of North America’s forested regions. Biomes are distinct large areas of Earth that include specific flora and fauna, such as deserts, prairies, Specialists (Species) and tropical forests. Have a narrow ecological niche. Niche Example: Giant Panda (Ailuropoda melanoleuca) Describes both the role played by a species in a biological community and the environmental factors Evolved from carnivorous ancestors to that determine its distribution. subsist almost entirely on bamboo. Must spend up to 16 hours a day eating to First defined by British ecologist Charles acquire enough nutrients. Elton (1900-1991) in 1927: Characteristics such as slow metabolism, o “Each species has a role in a slow movements, and a low reproductive community of species, and the niche rate help it survive on this specialized diet. defines its way of obtaining food, the relationships it has with other species, Conservation Concerns and the services it provides to its community.” The giant panda's narrow niche now Thirty years later, American limnologist G. endangers its survival. E. Hutchinson (1903-1991) proposed a Recent destruction of most of its native broader definition: bamboo forests has reduced its range and o Every species exists within a range of population to the margins of survival. physical and chemical conditions, The saguaro cactus is slow-growing and such as temperature, light levels, finely adapted to certain climatic conditions acidity, humidity, or salinity. but cannot persist in wetter or cooler environments. Types of Niches Due to their exacting habitat needs, specialists tend not to tolerate a) Spatial or Habitat Niche: Deals with the physical environmental change well. space occupied by organisms. Endemic Species b) Trophic Niche: Distinguished based on the food level of an organism. They occur only in one area or one type of environment. c) Multidimensional or Hypervolume Niche: Complex to understand, explained using Example: The giant panda is endemic to the fundamental and realized niches. mountainous bamboo forests of southwestern China. Generalists (Species) The saguaro is endemic to the Sonoran Desert. Tolerate a wide range of conditions. Exploit a wide range of resources. Specialists Often have large geographic ranges. In many organisms, genetic traits and intrinsic behaviors restrict the ecological niche. However, some species have complex social structures that enable them to expand the range of resources or environments they can utilize. Examples: o Elephants, chimpanzees, and dolphins learn from their social groups how to behave. o They can invent new ways of doing things when faced with novel opportunities or challenges. Competition and the Principle of Competitive Exclusion When two species compete for limited resources, one will typically gain the larger share, while the other may find a different habitat, die out, or adapt to minimize competition. G. F. Gause (1910-1986) Russian biologist known for the Principle of Competitive Exclusion: o “Complete competitors cannot coexist.” o No two species can occupy the same ecological niche for long. o The more efficient species will exclude the other, which may then disappear or adapt by developing a new niche. Resource Partitioning Resource partitioning allows several species to utilize different parts of the same resource and coexist within a single habitat. A classic example is the woodland warblers, studied by ecologist Robert MacArthur. Resources can be partitioned in both time and space.  POPULATIONS AND COMMUNITIES unit area, such as population mass per unit area. Population o Examples: ▪ The number of Lauan trees Group of interacting individuals, usually of per square kilometer in the same species, in a definable space, that Lucban. roughly occupy the same geographical area ▪ The number of Escherichia at the same time (e.g., fish population in a coli bacteria per milliliter in a pond). test tube. Individual members of the same population can either interact directly or may interact Population Dispersion with the dispersing progeny of other members of the same population. The pattern of spacing among individuals within Population members interact with a similar the boundaries of the population. environment and experience similar environmental limitations (e.g., a deer Individual members of populations may be population in a tropical forest). distributed over a geographical area in several The study of factors that affect the growth, different ways, including: stability, and decline of populations is population dynamics. Clumped distribution (attraction) Uniform distribution (repulsion) Population Size Random distribution (minimal interaction/influence) Population size depends on how the population is defined. Patterns of Dispersion If defined in terms of some degree of reproductive isolation, then the Clumped Distribution population’s size is the size of its gene pool. If defined in terms of some geographic o Clumped distribution may result from range, then the population’s size is the individual organisms being attracted to number of individuals living in the defined each other or being more attracted to area. certain patches within a range than to Ecologists typically focus on the latter others. definition, as it is both easier to measure and o The net effect is that some parts of the more practical for determining the impact of range will have a large number of a given population on a given ecosystem, or individuals, whereas others will contain vice versa. few or none. Population Density Uniform Distribution Given that a population is defined in terms of In a uniform distribution, individual some natural or arbitrarily defined organisms are spaced at approximately the geographical range, population density is same distance from one another. defined as the number of individual This type of distribution results from organisms per unit area or volume. individual organisms actively repelling each Different species exist at different densities other. in their environments, and the same species may achieve one density in one environment Patterns of Dispersion and another in a different environment. Population densities may also be determined Both clumping and uniform distributions suggest using measures other than population size per that:  1. Individual organisms are either interacting Local Extinction with one another (actively seeking each other out or actively avoiding each other). The loss of all individuals in a population. 2. All are competing with one another for the same limited resources, regardless of the Species Extinction overall population density. Occurs when all members of a species and its Random Distribution component populations go extinct. In a random distribution, the location of Population Decline individual organisms is only minimally influenced by interactions with other Scientists estimate that 99% of all species members of the same population. that ever existed are now extinct. Random distributions are uncommon. The ultimate cause of decline and extinction “Random spacing occurs in the absence of is environmental change. strong attractions or repulsions among Some extinctions are caused by the individuals of a population.” migration of a competitor. Demographics Population Growth The vital statistics of a population, particularly those Occurs when available resources exceed the that can impact present and future population size, number of individuals able to exploit them. include: Reproduction is rapid, and death rates are low, producing a net increase in the Population's age structure population size. Population's gender ratio The simplest case of population growth occurs when there are no limitations on All populations undergo three distinct phases of their growth within the environment. life cycle: Factors Influencing Population Growth 1. Growth 2. Stability Nearly all populations will tend to grow 3. Decline exponentially as long as there are resources available. Population Stability Most populations have the potential to expand at an exponential rate, since Often preceded by a “crash” since the reproduction is generally a multiplicative growing population eventually outstrips its process. available resources. Stability is usually the longest phase of a Key Factors population's life cycle. Birth rate and death rate are two of the most Population Decline basic factors that affect the rate of population growth. The decrease in the number of individuals in The intrinsic rate of increase is the birth rate a population. minus the death rate. Eventually leads to population extinction. The Exponential Curve Extinction Also known as a J-curve, it occurs when The elimination of all individuals in a group. there is no limit to population size.  Example: Female housefly (Musca The exponential growth equation is a very simple domestica). model; it is an idealized description of a real The growth of the housefly population just process. described is exponential, having no limit and possessing a distinctive shape when graphed A graph of exponential population growth is over time. described as a J curve because of its shape. Initially, Many species have the potential to produce the number of individuals added to a population can almost unbelievable numbers of offspring. be relatively small. However, the numbers begin to Consider a single female housefly (Musca increase rapidly with a fixed growth rate. domestica), which can lay 120 eggs. In 56 days, those eggs become mature adults, and Example: if half are female, each can lay another 120 eggs. When a population has just 100 individuals, At this rate, there can be seven generations a 2 percent growth rate adds just 2 of flies in a year, leading to the original fly individuals. being the grandparent of 5.6 trillion For a population of 10,000, that same 2 offspring. percent growth results in an increase of 200 If this rate of reproduction continued for 10 individuals. years, the entire Earth would be covered in several meters of housefly bodies. This demonstrates how growth accelerates as the Luckily, housefly reproduction, as with most population size increases. organisms, is constrained in a variety of ways: scarcity of resources, competition, In the real world, there are limits to growth. predation, disease, and accident. Carrying Capacity An exponential growth rate (increase in numbers per unit of time) is expressed as a constant fraction, Carrying Capacity refers to the mean or exponent, which is used as a multiplier of the number or biomass of animals that can be existing population. supported (without harvest) in a certain area of habitat. Mathematical Equation for Exponential Growth It represents a limit of sustainability that an environment has in relation to the size of a dN/dt=rNdN/dt = rNdN/dt=rN species' population. Understanding carrying capacity is helpful in Where: understanding the population dynamics of some species. d = change When a population exceeds the carrying N = number of individuals in the population capacity of its environment, resources dN = change in the number of individuals become limited and death rates rise. dt = change in time r = rate of growth Biomass The r term (intrinsic capacity for increase) is a Biomass is the total mass of living fraction representing the average individual organisms, such as plants and animals, in a contribution to population growth. specific unit of area or volume of habitat. It refers to the dry weight of all organic If r is positive, the population is increasing. matter contained in its organisms. If r is negative, the population is shrinking. If r is zero, there is no change, and If deaths exceed births, the growth rate becomes dN/dt=0dN/dt = 0dN/dt=0. negative, and the population may suddenly decrease, a change called a population crash or dieback. Population Cycles This predator-prey oscillation is described mathematically in the Lotka-Volterra model, Irregular cycles include outbreaks of named after the scientists who developed it. migratory locusts in the Sahara and tent caterpillars in temperate forests, representing Environmental limits lead to logistic growth. irruptive population growth. Immigration refers to the arrival of a species When resources are unlimited, populations grow into an area, while emigration refers to the exponentially; however, this growth slows as the departure from an area. carrying capacity of the environment is approached. Some species experience predictable cycles if simple factors are involved, such as the Factors Affecting Population Growth seasonal light and temperature-dependent bloom of algae in a lake. Often, immigration of a species into an area Cycles can be irregular if complex or emigration from an area also affects environmental and biotic relationships exist. population growth and declines. Populations may oscillate from high to low levels around the habitat’s carrying This population dynamic is called logistic growth capacity, which may be lowered if the habitat because of its changes in growth rate over time. is damaged. For example, moose and other browsers or The Logistic Curve grazers sometimes overgraze their food plants, leading to future populations finding Also known as an S-curve, the logistic curve less preferred food to sustain them until the illustrates the effect of a limiting factor, habitat recovers. specifically the carrying capacity of the environment. The 200-year record of furs sold at Hudson Bay Mathematically, this growth pattern is Company trading posts in Canada reveals important described by the following equation, which insights into population dynamics. incorporates a feedback term for carrying capacity (K) into the exponential growth The ecologist Charles Elton demonstrated that the equation: numbers of Canada lynx (Lynx canadensis) fluctuate on about a 10-year cycle that mirrors, dN/dt = rN(1 - N/K) slightly out of phase, the population peaks of snowshoe hares (Lepus americanus). Where: Predator-Prey Dynamics dN/dt = change in population size over time r = intrinsic growth rate When the hare population is high, the lynx N = current population size prosper on abundant prey, leading to good K = carrying capacity of the environment reproduction and population growth. Eventually, the abundant hares overgraze This equation reflects how population growth slows vegetation, decreasing their food supplies, as it approaches the carrying capacity. which results in a decline in hare populations. For a while, lynx benefit because starving The Logistic Curve hares are easier to catch than healthy ones. As hares become scarce, however, so do lynx. In the logistic growth equation: When hares are at their lowest levels, their food supply recovers, and the whole cycle dN/dt = change in numbers over time starts over again. rN = exponential growth rate K = carrying capacity N = population size  (K−N)/K(K - N)/K(K−N)/K = relationship Internal factors such as slow growth and maturity, between population size at any given time body size, metabolism, or hormonal status can and the carrying capacity reduce reproductive output. Often, crowding exacerbates these factors. Key Points: For example, overcrowded house mice (more If N is less than K, the rate of population than 1,600/m³) average 5.1 babies per litter, change will be positive (population grows). while uncrowded house mice (fewer than If N is greater than K, the rate of population 34/m³) produce 6.2 babies per litter. change will be negative (population declines). All these factors are density-dependent. Density-Dependent Factors Species Response to Limits: r and K-Selected Species As population size increases, the effects of density-dependent factors intensify. These r-Selected Species factors often include competition, predation, and disease. r-selected species depend on a high rate of reproduction and growth (denoted as r) to Density-Independent Factors secure their place in the environment. They are adapted to employ a high These factors are affected by external and reproductive rate to overcome the high internal conditions and impact the population mortality rates of their often neglected regardless of its size. Examples include offspring. drought, flooding, and landslides, all of These species may even overshoot carrying which can increase mortality rates capacity and experience population crashes; irrespective of population size. however, as long as vast quantities of young are produced, a few will survive. Population Growth Potential Related to Life Examples: Dandelions and barnacles. History Organisms with r-selected, or exponential, growth The age at which an organism reproduces patterns tend to occupy low trophic levels in their affects the rate of population increase. ecosystems or serve as successional pioneers. Some organisms grow fast, reproduce quickly, and have abundant offspring each Characteristics of r-Selected Species reproductive cycle. Others grow slowly, reproduce at a later age, Niche generalists occupy disturbed or new and have few offspring per cycle. Most environments. organisms fall somewhere intermediate They grow rapidly, mature early, and between these two extremes. produce many offspring with excellent dispersal abilities. Density-Independent Factors As individual parents, they provide little care for their offspring or protection from External factors include habitat quality, food predation. availability, and interactions with other organisms. They invest their energy in producing huge As populations grow: numbers of young, counting on some to survive to adulthood. Food becomes scarcer, leading to increased competition for resources. K-Selected Species With a larger population, there is an increased risk that disease or parasites will spread, and that predators will be attracted to the area. K-selected species are organisms that reproduce Relationship Between Diversity and Abundance more conservatively, characterized by: Diversity and abundance are often related. Longer generation times Communities with high diversity may have Late sexual maturity few individuals of any one species, as many Fewer young different species share available resources. As a general rule, species diversity is These species are usually: greatest at the equator and decreases toward the poles. Larger in size Although the number of species is lower near Long-lived the poles, the abundance of particular species Mature slowly can be very high. Produce few offspring in each generation Have few natural predators Patterns Produce Community Structure K-selected species are adapted for slower growth The spatial distribution of individuals, species, and conditions near the carrying capacity (K) of their populations can influence diversity, productivity, environment. and stability in a community. COMMUNITY AND ECOSYSTEM Niche diversity and species diversity can increase as the complexity of the landscape Community increases. For example, varied habitats and microenvironments provide more No species is an island; it always lives with other opportunities for different species to thrive species in a biological community within a and interact, enhancing overall community particular environment. Interactions among species structure. significantly affect biological communities. Resilience and Complexity The many species in an area together produce the basic properties of biological communities and The relationship between complexity and resilience ecosystems. The main properties of interest to has long been a significant question in ecology. ecologists are: The more complexity a community 1. Diversity and abundance possesses, the more resilient it is when 2. Community structure and patchiness disturbances occur. If many different species occupy each Diversity and Abundance trophic level, some can compensate if others are stressed or eliminated by external forces, Diversity refers to the number of different species in thereby maintaining the community's overall an area, or the number per unit area. It is important stability and function. because it indicates the variety of ecological niches and genetic variation in a community. Examples Resilience and Community Complexity include: Often, diversity is thought of in terms of species The number of herbaceous plant species per counts, but another important aspect is community square meter of the African savanna. complexity. The number of bird species in Costa Rica. The total number of insect species on Earth. Complexity refers to the number of trophic levels in a community and the number of Abundance refers to the number of individuals of a species at each of those levels. particular species (or group) in an area.  A complex community may have many Resists changes despite disturbances. trophic levels, with groups of species Springs back resiliently after disturbances. performing similar functions. Supports the same species in approximately the same numbers as before the disturbance. For example, in tropical rainforests, herbivores form guilds based on their specialized feeding Communities Are Dynamic and Change Over strategies, including: Time Fruit-eaters When a fire sweeps through a forest, it's common to Leaf-nibblers say that the forest was destroyed, but this description Root-borers is often inaccurate. Seed gnawers Sap-suckers In many cases, fire is beneficial for a community. It can release nutrients in a This complexity enhances the community's burned grassland or facilitate the resilience to disturbances. regeneration of aging trees in a coniferous forest. Resilience and Productivity Dramatic, periodic change can be a normal part of ecosystem dynamics, contributing to Another factor that contributes to resilience is overall health and resilience. Such changes productivity. can promote diversity and allow for new growth and species to emerge, demonstrating Primary productivity refers to the the adaptability of ecosystems over time. production of biomass through photosynthesis. Succession Describes Community Change Plants, algae, and some bacteria produce biomass by converting solar energy into Succession is the process by which organisms chemical energy. occupy a site and change its environmental Primary productivity can be measured in conditions, gradually paving the way for a different terms of units of biomass per unit area per type of community. year (e.g., grams per m² per year). Types of Succession Factors Influencing Productivity 1. Primary Succession Productivity depends on several environmental o This occurs in land that is bare of soil, factors, including: such as a sandbar, rock surface, or volcanic flow. It is colonized by Light levels living organisms where none existed Temperature before. Moisture 2. Secondary Succession Nutrient availability o This happens after a disturbance, when a new community develops Higher productivity often leads to greater resilience from the biological legacy of the in communities, as it supports a larger and more previous one. This can occur in areas diverse array of species. where soil remains intact, such as after a fire, flood, or human activity. Resilience, Complexity, and Stability Primary Succession Stability is another important property that varies among ecosystems. A stable ecosystem: Pioneer species are the first to colonize barren environments. These organisms, such  as microbes, mosses, and lichens, can of understanding and managing both natural withstand harsh conditions and limited and anthropogenic disturbances to maintain resources. They play a crucial role in ecosystem health. modifying the environment, making it more hospitable for subsequent species. Secondary Succession Secondary succession is evident in various disturbed environments, such as abandoned farm fields, clear-cut forests, and disturbed suburbs or lots. In these areas, soil, seeds, and residual plant roots may still be present, allowing for a quicker recovery and establishment of new plant communities compared to primary succession. This process often leads to the re- establishment of a more complex community over time. The Equilibrium Between Biotic and Abiotic Factors There must be a delicate balance between biotic (living) and abiotic (non-living) factors in ecosystems. Disturbance Disturbance is defined as any force that disrupts established patterns of species diversity, abundance, community structure, or community properties. Disturbances occur frequently in ecosystems and can include events such as landslides, mudslides, hailstorms, earthquakes, hurricanes, tornadoes, tidal waves, wildfires, and volcanoes. Human-Induced Disturbances People also cause disturbances in various ways. For example, Aboriginal people historically set fires, introduced new species, harvested resources, and altered communities. In contrast, disturbances caused by modern technological societies are often much more obvious and can be irreversible, leading to significant and lasting impacts on ecosystems. This highlights the importance  TROPHIC STRUCTURE: FOOD CHAIN, First Trophic Level FOOD WEB & BIOMASS PYRAMID o Food Source: Prepares their food o Examples: Green plants, algae Trophic Levels Second Trophic Level o Food Source: Feeds on producers Trophic levels refer to the position of organisms in o Examples: Grasshoppers, butterflies, a food chain, food web, or ecological pyramid, deer, cows based on their feeding patterns. Third Trophic Level o Food Source: Feeds on primary Trophic levels are shown in a series or consumers succession to represent energy flow from o Examples: Frogs, rats, mice, one level to the next. sparrows The position of a trophic level depends on Fourth Trophic Level the number of steps an organism takes from o Food Source: Feeds on secondary the start of the food chain until its consumers consumption. o Examples: Snakes, owls Fifth Trophic Level Structure of Food Chains o Food Source: Feeds on tertiary consumers Food chains start with the producer, which o Examples: Hawks occupies the bottom of the food chain, representing the first trophic level. First Trophic Level: Producers Food chains end with the apex consumer, whose trophic level depends on its prey: Producers, also known as autotrophs, are o If it consumes a primary consumer, found at the base of food chains and it is at the third trophic level. ecological pyramids. o If it feeds on a tertiary consumer, it These organisms include photosynthesizing is at the fourth trophic level. organisms such as algae and plants. Producers convert the sun's energy into Trophic Levels glucose and biomass using inorganic compounds like water and carbon dioxide. An organism’s feeding status in an ecosystem is They store glucose as energy and release expressed as its trophic level (from the Greek word oxygen into the atmosphere. ‘trophe’, meaning food). In terrestrial ecosystems, primary production is carried out by vascular plants such as Food Chain ferns, flowering plants, and trees. In marine ecosystems, seaweed and algae A food chain is a succession of organisms fulfill the role of primary producers. that eat other organisms and may themselves be consumed. Second Trophic Level: Primary Consumers It represents a sequence of organisms in a natural community, where each link in the Primary consumers cannot make their own chain feeds on the one below and is eaten by food; they obtain energy by consuming the one above. autotrophs. There are seldom more than six links in a They are primarily herbivores (or food chain, with plants at the bottom omnivores) that feed directly on plants or (producers) and the largest carnivores at the algae. top (apex consumers). Examples include caterpillars, insects, grasshoppers, termites, and Trophic Levels hummingbirds. Common primary consumers are herbivores such as cows, goats, and pigs.  Many primary consumers are specialists, At the top of the ecological pyramid are meaning they only eat specific types of quaternary consumers that feed on tertiary autotrophs or producers. consumers. They act as intermediaries, making the Quaternary consumers are apex predators energy stored in plants accessible to other with no natural predators; they typically die organisms. of natural causes. Primary consumers transfer energy from Examples include carnivorous mammals plants to upper trophic levels as they such as tigers and lions. consume autotrophs. In aquatic ecosystems, sharks, piranhas, and barracudas are examples of quaternary Third Trophic Level: Secondary Consumers consumers, along with dolphins, seals, walruses, and sea lions. Secondary consumers consist of These organisms feed on smaller fish and heterotrophs, primarily carnivores and other marine organisms. omnivores that feed on producers (plants) and primary consumers (meat) to obtain Humans Feed at More Than One Trophic Level energy. They link herbivores and top-level Primary Consumers: When humans eat predators, transferring energy to higher vegetables, they are classified as primary trophic levels. consumers. The term carnivore comes from the Latin Secondary Consumers: When consuming word meaning “meat eater.” cows, goats, and pigs, humans act as Secondary consumers consume primary secondary consumers. consumers, which may include animals, Tertiary Consumers: When eating salmon, plants (e.g., the Venus flytrap), or fungi that humans are considered tertiary consumers. trap and consume small organisms. Obligate carnivores, such as cats, rely Which Trophic Level is Most Vulnerable to solely on animal flesh. Extinction? Facultative carnivores, like dogs, consume both animal and non-animal food. Top Predators: The top predators, typically Reptiles, such as snakes and certain lizards, found at the fourth or fifth trophic levels, are typically eat smaller animals. the most vulnerable to extinction. Omnivores consume a variety of foods, including both plant-based and animal- Many Consumers Feed at More Than One derived sources. Examples include humans, Trophic Level bears, raccoons, chickens, cockroaches, and crayfish. Primary Consumers: Humans are primary Omnivores exhibit dietary flexibility, consumers when they eat vegetables. allowing them to consume plants, animals, Secondary Consumers: They become algae, and fungi. secondary consumers when they consume cows, goats, and pigs. Fourth Trophic Level: Tertiary Consumers Tertiary Consumers: When eating salmon, humans are classified as tertiary consumers. Tertiary consumers are primarily carnivores that prey on secondary Which Trophic Level is Most Vulnerable to consumers. Extinction? Examples include reptiles, foxes, and hawks. Top Predators: In any ecosystem, the top Predatory birds such as eagles, vultures, predators are the most vulnerable to falcons, hawks, and owls hunt animals. extinction. They are typically found in the fourth or fifth trophic levels, depending on Fifth Trophic Level: Quaternary Consumers the food chain. Decomposers in the Food Chain land, including the largest dinosaurs, are herbivores. Trophic Levels: In some food chains, o Granivore: Herbivores (like rodents) decomposers occupy the sixth trophic level, that primarily eat grains and seeds. preceded by a fifth level occupied by o Omnivore: Animals that eat both scavengers (e.g., insect larvae). plant and animal material (e.g., Detritivores: Decomposers are also known humans). as detritivores, as they consume decaying o Insectivore: Predatory animals (such or dead plants and animals. as shrews or bats) that mainly eat insects. Role of Decomposers 3. Secondary Consumers (Third Trophic Level): Decomposition Process: Decomposers o Definition: Carnivorous animals that carry out the process of decay, breaking feed on herbivores. down complex organic matter—typically o Predator: Animals that kill and feed dead animals or plant matter—into simpler upon other animals. In rare cases, forms. animals may kill and eat their mates. Nutrient Recycling: Through o Prey: Animals that are hunted and decomposition, minerals and nutrients are killed for food. released back into the soil, allowing them to 4. Tertiary Consumers (Fourth Trophic be reused by primary producers. Level): Organisms Involved: Decomposers include o Definition: Larger carnivores that bacteria, fungi, and other organisms that kill and eat smaller carnivores and break down organic material. herbivores from the lower trophic Importance: Although decomposers lie levels. outside of the typical food chain, they play a crucial role in recycling nutrients and Heterotrophic Nutrition maintaining ecosystem health. Heterotrophic: Organisms unable to Trophic Levels in a Food Chain synthesize their own energy-rich carbohydrates; they rely on other organisms. Definition: A trophic level is a level of o Parasitic Heterotrophs: Live on nutrition or “link” in a food chain. other living organisms. Chain Length: Following the Second Law o Saprophytic Heterotrophs: Depend of Thermodynamics, food chains seldom on dead, decaying organic matter. have more than six links. Food Web and Trophic Levels Trophic Levels Explained Food Web: A complex pattern of 1. Producers (First Trophic Level): interconnected food chains in a community, o Definition: Autotrophic showing how organisms are related through photosynthetic plants that occupy the arrows that indicate the direction of energy first level. flow. o Autotrophic: Organisms that synthesize energy-rich carbohydrate Trophic Levels and Energy Transfer molecules. 2. Primary Consumers (Second Trophic Energy Transfer: Energy moves from Level): lower to higher trophic levels in a food o Definition: Plant eaters (herbivores). chain. o Herbivore: Animals that eat plant Energy Efficiency: Only about 10% of the material. The largest animals on energy at one trophic level is passed to the  next. The remainder is lost as heat or used in ▪Energy Loss: metabolic processes. 10,000 - 1,000 = 9,000 kcal 2. Calculate Percent Decrease: Energy Distribution in Trophic Levels o Percent decrease = (9,000 kcal / 10,000 kcal) × 100 = 90% First Trophic Level: 3. Repeat for Other Trophic Levels: o Energy: 1,000 kilocalories o This method can be applied to Second Trophic Level: calculate percent decreases for o Energy: 100 kilocalories Trophic Levels 3, 4, and 5. Third Trophic Level: o Energy: 10 kilocalories General Trends Fourth Trophic Level: o Energy: 1 kilocalorie In most ecosystems, the percent decrease in Fifth Trophic Level: energy from one trophic level to the next o Energy: 0.1 kilocalories typically ranges from 80% to 90%. Energy Pyramid Definition of Biomass Pyramid Pyramidal Shape: Due to energy loss at A biomass pyramid is a graphical each trophic level, food chains rarely exceed representation that illustrates the total four levels. biomass or organic matter at each trophic Eltonian Pyramid: Named after ecologist level in an ecosystem, demonstrating the Charles Elton, who conceptualized this flow of energy from producers to energy distribution in 1927. consumers. Energy Transfer and Decrease in Trophic Levels What is Biomass? Example of Energy Transfer: In ecology, biomass is defined as the o It takes approximately 100 kg of cumulative mass of all living or organic clover to produce 10 kg of rabbit, entities present within a specific ecosystem which in turn produces 1 kg of fox. at a given moment. Pyramid of Mass & Numbers Types of Biomass Mass and Numbers: Both the mass 1. Species Biomass: (weight) and number of organisms typically o Refers to the total mass of all decrease along a food chain. individuals within a single species in o Example: Grass → Grasshoppers an ecosystem. This includes → Frog → Snakes → Hawk everything from microscopic o It requires a significant amount of organisms to larger beings, such as grass to sustain a single hawk at the humans. top of the food chain. 2. Community Biomass: o Represents the combined mass of all Percent Decrease at Each Trophic Level species that inhabit a particular community. 1. Calculate Energy Loss: o For Trophic Level 2: Biomass provides a quantitative measure of ▪ Starting with 10,000 kcal of the organic matter within an ecosystem, grass (Level 1) and 1,000 offering valuable insights into its health and kcal from grasshoppers vitality. (Level 2): Trophic Levels and Biomass In the biomass pyramid, energy flows from producers to consumers, converting into The energy pyramid represents the biomass biomass as it moves through the trophic of organisms at each trophic level. levels. With less energy available at each trophic level, there are fewer organisms at Types of Biomass Pyramids successive levels. Consequently, the first trophic level has the There are two main classifications of most biomass, which decreases as we move biomass pyramids: up the pyramid. o Upright Pyramid: Commonly found This representation is known as the in ecosystems like grasslands and pyramid of biomass. forests, where biomass decreases at higher trophic levels. What is a Biomass Pyramid? o Inverted Pyramid: Typically seen in marine environments, where a In ecology, the intricate relationship small number of large consumers can between energy, biomass, and productivity support a large biomass of producers. across various trophic levels is visually represented by the ecological pyramid or Biomass Pyramid Overview Eltonian pyramid. A biomass pyramid illustrates the The Biomass Pyramid is a graphical representation cumulative biomass or organic matter that showcases the distribution of biomass across distributed across different trophic levels different trophic levels in an ecosystem. within an ecosystem. The biomass pyramid elucidates the process Types of Biomass Pyramids of energy transmission from producers to consumers. 1. Upward Pyramid Only about 10% of energy is passed to the next trophic level, while the remaining Structure: Characteristic of most terrestrial energy is used for metabolic activities or ecosystems, featuring a broad base for excreted. primary producers, with progressively decreasing sizes of subsequent trophic Biomass levels. Distribution: Biomass is the total mass of living entities o Primary Producers: Occupying the within a specific trophic level, typically base, the biomass of autotrophs quantified as dry weight in grams or calories (primary producers) is at its per unit area. maximum. The quantification of biomass is often o Primary Consumers: Positioned achieved using a bomb calorimeter. above producers, their biomass is less than that of the primary Biomass and Trophic Levels producers. o Secondary Consumers: Their The biomass at a specific trophic level biomass is even lower than that of reflects the living material available within primary consumers. that level's organisms per unit area. o Higher Trophic Levels: As one This pyramid’s structure is based on the ascends the pyramid, biomass principles of thermodynamics, which state continues to diminish, resulting in that energy is conserved but transforms from minimal biomass at the apex. one state to another. Inverted Pyramid Energy Flow in the Biomass Pyramid  Structure: Predominantly observed in many Shape: Narrow at the top and broad at the aquatic ecosystems, this pyramid exhibits an bottom inverted shape. Proportion of Biomass: More biomass at Distribution: the bottom than at the top o Primary Producers: The base is Trophic Levels: Higher trophic levels are at relatively narrow, consisting mainly the top of phytoplankton. These microscopic Food Chain: Long food chain with few organisms can reproduce rapidly, organisms at higher levels leading to a swift turnover. Ecosystem: Stable and balanced ecosystem o Consumers: As one moves up the pyramid, the biomass of consumers Inverted Pyramid of Biomass consistently surpasses that of the producers, giving the pyramid its Shape: Broad at the top and narrow at the inverted appearance. bottom Proportion of Biomass: More biomass at Comparison with Upward Pyramid the top than at the bottom Trophic Levels: Higher trophic levels are at While the upward pyramid reflects the typical the bottom structure of terrestrial ecosystems, the inverted Food Chain: Short food chain with many pyramid underscores the unique dynamics of organisms at higher levels aquatic ecosystems, especially where rapid Ecosystem: Disturbed or degraded reproduction of primary producers is observed. Both ecosystem types provide valuable insights into the distribution of organic matter and energy flow within different ecosystems. Upright Pyramid of Biomass Characteristics: Represents a stable and balanced ecosystem. Structure: o Primary Producers: A large amount of plants. o Primary Consumers: A smaller amount of herbivores. o Secondary and Tertiary Consumers: An even smaller number of carnivores. Inverted Pyramid of Biomass Characteristics: Occurs in disturbed or degraded ecosystems. Structure: o Primary Producers: Fewer primary producers compared to consumers. o Primary Consumers: A higher number, leading to an imbalance in the food chain. Upright Pyramid of Biomass  NUTRIENT AND BIOGEOCHEMICAL This occurs as animals and plants consume CYCLES soil nutrients; the nutrients are released back into the environment via death and Matter decomposition. Inorganic nutrients cycle through many Stored: Nutrients can be kept in various organisms and enter into the atmosphere, the forms within organisms and the environment. oceans, and rocks. Transformed: Nutrients can be changed into different molecules during biological Important of Nutrient Cycle processes. Transferred: Nutrients move from one Continuous cycles organism to another through consumption. Nutrients pass through living organisms Returned: Nutrients can revert to their initial and back to the environment configuration through processes like death Recycling of important nutrients needed for and decomposition. life Renewal of resources to support life on Nutrient Cycle Earth Human bodies change over time; food is the It is a system where energy and the flow of fuel for those changes matter are transferred between living Basic nutrients needed: amino acids, organisms and non-living parts of the carbohydrates, fatty acids, vitamins, environment. minerals, water Essential Nutrients include: Cycling of Materials Non-mineral elements (Carbon, Hydrogen, Sustains biotic life and conditions on Earth Oxygen), which make up 95% of the mass of by enabling oxygen, carbon, etc., to all living organisms. These nutrients come circulate. from carbon dioxide in the air and water Human activities impact nutrient cycles by (H₂O). altering the balance of carbon dioxide in the Mineral elements categorized into atmosphere. macronutrients and micronutrients: Burning of fossil fuels and deforestation o Macronutrients (e.g., Nitrogen (N), have led to an increase in atmospheric Phosphorus (P), Potassium (K), carbon dioxide levels, affecting the growth Calcium (Ca), Magnesium (Mg)) are and nutrient uptake of plants. needed in large quantities by plants to perform basic functions. Their Importance of Material Cycle availability can limit the growth of organisms. In Engineering, Closing the Loop of Material o Micronutrients are required in much Cycles (CLMC) is defined as: smaller amounts but are vital for growth and metabolism. Examples “A construction constituting materials and building include Boron (B), Copper (Cu), Iron elements that can be recovered from buildings and (Fe), Manganese (Mn), and Zinc (Zn). infinitely recycled through natural or industrial processes” (Ayres and Ayres, 1996). Nutrients are chemical substances found in every living organism and are essential for every process in How Do Earth Materials Cycle? an organism's body. They help organisms to derive energy, build muscles, cure deficiency diseases, The rock cycle is driven by two forces: fulfill mineral needs, and provide fluids to various parts of the body.  1. Earth's internal heat engine, which moves carbon, nitrogen, and water, are material around in the core and mantle, continuously recycled. leading to slow but significant changes within the crust. Chemical Processes in Biogeochemical Cycles 2. The hydrological cycle, which is the movement of water, ice, and air at the Chemical processes are carried out by living surface, powered by the sun. organisms. It involves the movement and Nutrient Cycling in Forest Ecosystems transformation of chemical elements and compounds in the atmosphere and Earth's Nutrient cycle: Involves animals, plants, crust, across land, water, and air. fungi, and bacteria living above- and below- Both the environment and living organisms ground, along with mineral components of are needed to continuously process chemical soil, dead leaves, wood, and water from rain elements. and snowfall. Studying biogeochemical cycles is crucial for Three materials that cycle through understanding how ecosystems resist ecosystems are: ester monomers, nitrogen Anthropocene stresses and for modeling the (N), and hydrogen (H). sustainable functioning of human-impacted Trees and other plants absorb mineral and ecosystems, such as agricultural soils. non-mineral nutrients from the soil through their roots. CO2 Cycle The nutrients are stor