REVIEWER ENV SCIENCE

Group 1 Environmental Science is the study of the interactions between the physical, chemical, and biological components of the environment. It examines how humans affect the environment and how the environment, in turn, affects humans. Environmental Science integrates knowledge from biology, chemistry, physics, geology, and social sciences to address environmental issues and promote sustainable solutions. SCOPE / FIELD OF ENVIRONMENTAL SCIENCE Environmental Science is a multidisciplinary field that covers a wide range of topics. Its main scopes include: 1. Ecology – Study of interactions among organisms and their environment. 2. Natural Resources Management – Study and management of resources like water, soil, minerals, and forests. 3. Environmental Pollution – Understanding the sources, effects, and control of pollutants. 4. Environmental Health – Study of environmental factors affecting human health. 5. Environmental Policy and Management – Development of strategies, laws, and regulations to protect the environment. 6. Climate Change and Global Warming – Study of changing climate patterns and their impact. 7. Sustainable Development – Finding ways to meet human needs while protecting the environment for future generations. IMPORTANCE OF ENVIRONMENTAL SCIENCE 1. Protects Natural Resources – Helps in the sustainable use of resources like water, air, and forests. 2. Addresses Environmental Problems – Provides solutions for issues like pollution, climate change, and biodiversity loss. 3. Promotes Human Health – Reduces exposure to harmful pollutants and improves overall quality of life. 4. Informs Policy-Making – Guides governments and organizations in creating laws and regulations for environmental protection. 5. Encourages Sustainable Practices – Supports development that balances economic growth with environmental conservation. ENVIRONMENTAL INTERRELATIONSHIPS Environmental issues are rarely isolated. They exist in a web of cause and effect known as The Nexus: • Human activities (Social) > Resource extraction (Economic) > Habitat loss (Environmental)..

Example: Cutting down a forest (deforestation) doesn’t just remove trees; it affects local rainfall, increases carbon dioxide levels, and displaces wildlife. ECOLOGY VS. ENVIRONMENTAL SCIENCE • ECOLOGY: A branch of biology focused on how organisms interact with one another and their physical environment. (The "How it works"). • ENVIRONMENTAL SCIENCE: A broader field that incorporates ecology but also focuses on human impact and finding solutions to problems. (The "How to fix it"). UNIFYING ENVIRONMENTAL THEMES What are Unifying Environmental Themes? These are core concepts that explain how living things, natural systems, and human activities interact within the environment. They help people understand environmental systems and make informed choices about how to care for the planet. 1. INTERDEPENDENCE: Explains how living organisms and the physical environment are connected and rely on one another for survival; changes in one part affect the entire ecosystem. 2. DIVERSITY AND STABILITY / CHANGE: Means that ecosystems with many species are stronger, balanced, and better able to recover from changes. 3. BALANCE OF NATURE: Describes how natural systems maintain stability through interactions among organisms and environmental processes. 4. FINITENESS OF RESOURCES: Emphasizes that Earth’s natural resources exist in limited amounts and must be managed carefully to avoid depletion. 5. MATERIAL CYCLES: Explains how essential elements continuously move through air, water, soil, and living organisms to support life. 6. POPULATION GROWTH AND CARRYING CAPACITY: Explains that population size increases over time but is limited by the amount of resources an environment can provide. 7. STEWARDSHIP: Means using natural resources responsibly and protecting ecosystems through human care and management. 8. SUSTAINABLE DEVELOPMENT: Focuses on improving human well- being while conserving natural systems for long-term environmental health. 9. COOPERATION: Means that living organisms, humans, communities, and governments work together to protect the environment and solve environmental problems..

Group 2 I. ENVIRONMENTAL WORLDVIEWS A worldview explains how people understand the relationship between humans and nature. There are three major environmental worldviews: 1. Anthropocentrism (Human- centered): Humans are the most important; nature is valuable because it benefits us. 2. Biocentrism (Life-centered): All living organisms have intrinsic value; humans are not superior to other life forms. 3. Ecocentrism (Earth-centered): Focuses on the entire ecosystem (both living and non-living); values balance and biodiversity. Importance of Worldviews: Worldviews are critical because they influence: • Environmental laws and government policies. • Business decisions and corporate ethics. • Personal lifestyle choices. II. TYPES OF ENVIRONMENTAL ETHICS Environmental ethics is categorized into two main approaches: • Individual Environmental Ethics: Focuses on each person’s moral responsibility. It emphasizes that daily actions—such as recycling, conserving water, and reducing waste—can protect the environment. • Holistic Environmental Ethics: Focuses on protecting entire ecosystems and communities rather than just individuals. It supports broad environmental laws and sustainable development. III. FOREFATHERS OF ENVIRONMENTAL ETHICS The Industrial Revolution (18th–19th century) led to rapid growth, but also increased pollution and deforestation, sparking the work of these early thinkers: 1. Henry David Thoreau: Advocated for simple living and harmony with nature. He believed nature has intrinsic value beyond economic use and wrote Walden to emphasize respect for the natural world. 2. John Muir: The founder of the modern conservation movement. He argued for the preservation of wilderness areas and believed nature should be protected for its own sake. 3. George Perkins Marsh: One of the first to warn about human-caused environmental damage. In his book Man and Nature, he highlighted how industrial activities degrade ecosystems..

IV. ENVIRONMENTAL ATTITUDES & PERSPECTIVES Different ethical attitudes guide how society treats the planet: • Development Ethics: Focuses on balancing economic growth with environmental protection. It promotes sustainable development to ensure progress doesn't harm future generations. • Preservation Ethics: Aims to protect nature from all human interference. It values nature for its own sake and supports strict protection of natural areas. • Conservation Ethics: Encourages the responsible and sustainable use of natural resources. It supports controlled consumption rather than total preservation. • Corporate Environmental Ethics: The responsibility of businesses to protect the environment through ethical practices, such as reducing waste and pollution. • Environmental Justice: The fair treatment of all people in environmental policies. It seeks to protect marginalized communities and prevent environmental discrimination. • Global Environmental Ethics: The concept of shared global responsibility and international cooperation to address worldwide environmental issues. Group 3 I. EVOLUTION OF THE ECOSYSTEM CONCEPT The concept of the ecosystem has evolved through three major stages: • Origin (1935): Coined by Arthur Roy Clapham and popularized by Arthur Tansley. • Functional Shift (1942): Raymond Lindeman introduced the "Trophic- Dynamic" model. • Modern View: Developed further by the Odum brothers. The Ecosystem Concept Properties: 1. Functional Unit 2. Open System 3. Dynamic Properties II. LEVELS OF BIOLOGICAL ORGANIZATION Level Definition Ecological Focus Organism A single living individual. Survival and adaptation to the physical environment. Population A group of organisms of the same species in one area. Population growth and competition for resources..

Level Definition Ecological Focus Community All populations of different species in an area. Predation, symbiosis, and niche partitioning. Ecosystem Community plus the abiotic environment. Energy flow and nutrient cycling. Biome Regional group of ecosystems with similar climate. Global patterns of biodiversity and climate. Biosphere The global sum of all life- supporting regions. Earth-scale carbon cycle and planetary health. III. ECOSYSTEM STRUCTURE • Abiotic Factors (Non-living): Light, Water, Temperature, Soil Nutrients, and Gases. • Biotic Factors (Living): Producers, Consumers, and Decomposers. IV. INTERRELATED SCIENTIFIC PRINCIPLES 1. For Matter (Matter Cycles): Matter is neither created nor destroyed. It moves in biogeochemical cycles (Carbon, Nitrogen, Phosphorus, Oxygen). Decomposers play a vital role in recycling these nutrients. 2. For Energy (Energy Flows): Energy flows in a one-way stream. It enters as sunlight, is captured by producers, passed to consumers, and is lost as heat at each level. V. LAWS OF THERMODYNAMICS • First Law (Conservation of Energy): Energy cannot be created or destroyed, only transformed from one form to another. • Second Law (Entropy and Efficiency): With each transformation, some energy is lost as heat, increasing entropy (disorder) in the system. • The 10% Rule: Approximately 90% of energy is lost as heat at each trophic level, which limits the length of food chains. VI. FOOD CHAINS, WEBS, AND TROPHIC LEVELS • Food Chain: A linear representation of energy flow. • Food Web: Interconnected chains showing the complexity of an ecosystem. • Trophic Levels: o Level 1: Producers (Make their own food/Photosynthesis)..

o Level 2: Primary Consumers (Herbivores/Eat plants). o Level 3: Secondary Consumers (Carnivores/Eat herbivores). o Level 4: Tertiary Consumers (Top predators). VII. TYPES OF ECOLOGICAL PYRAMIDS 1. Energy Pyramid: Shows energy flow. It is always upright because only 10% of energy transfers to the next level. 2. Biomass Pyramid: Shows the total mass of organisms. Usually upright but can be inverted in aquatic ecosystems. 3. Numbers Pyramid: Shows the number of individual organisms. Can be upright or inverted depending on the specific ecosystem. VIII. PRODUCTIVITY AND RESPIRATION • Primary Productivity: o GPP (Gross Primary Productivity): Total energy captured by plants. o R (Respiration): Energy used by plants for their own survival. o NPP (Net Primary Productivity): The energy available to herbivores (NPP = GPP - R). • Secondary Productivity: Refers to the rate at which consumers convert the chemical energy of their food into their own new biomass (Growth and Reproduction). • Secondary Productivity: Refers to the rate at which consumers convert the chemical energy of their food into their own new biomass (Growth and Reproduction). Group 4 I. CONCEPT OF MATERIAL CYCLING Material cycling (or biogeochemical cycling) is the continuous movement of essential elements through the biotic (living) and abiotic (non-living) components of an ecosystem. The Major Cycles: 1. Water 2. Carbon 3. Nitrogen 4. Phosphorus 5. Sulfur II. THE WATER CYCLE (HYDROLOGIC CYCLE) The continuous movement of water on, above, and below the surface of the Earth. Water changes form (liquid, gas, or solid) to support life, regulate climate, and move nutrients. Key Fluxes (Processes):.

• Evaporation: Liquid water changes to gas (water vapor) due to heat from the sun. • Transpiration: Water released from plants into the atmosphere through tiny leaf openings called stomata. • Sublimation: Ice or snow changes directly into water vapor, bypassing the liquid phase. • Condensation: Water vapor cools and changes back into liquid water. • Deposition: The direct change of water vapor into solid ice without becoming liquid. • Precipitation: Condensed water or ice crystals fall to Earth (rain, snow, etc.) due to gravity. • Infiltration: The movement of water into the soil surface. • Percolation: The downward movement of water through deeper soil and rock layers. • Runoff: Water that flows over the land surface toward rivers, lakes, and oceans. • Transportation: The movement of water through the atmosphere as vapor or clouds. III. THE CARBON CYCLE Known as "Nature's Great Recycler," the carbon cycle moves carbon through the atmosphere and food chain. • Step 1: Photosynthesis: Plants act as "natural carbon vacuums," taking in $CO_$ to create energy. • Step 2: Consumption & Respiration: Carbon moves from plants to animals to humans; $CO_$ is released back into the air through breathing. • Step 3: Decomposition: Bacteria and fungi break down dead organisms, releasing stored carbon. • The "Slow" Cycle: Involves the long- term storage of carbon in rocks and fossil fuels. IV. THE NITROGEN CYCLE A process where nitrogen moves through air, soil, and water. Most organisms cannot use nitrogen gas ($N_$) directly from the air. 1. Nitrogen Fixation: Bacteria or lightning convert nitrogen gas ($N_$) into ammonia ($NH_$). 2. Nitrification: Bacteria convert ammonia into nitrites and then into nitrates. 3. Nitrogen Assimilation: Plants absorb the nitrates through their roots. 4. Ammonification: Decomposers turn dead matter and waste back into ammonia. 5. Denitrification: Bacteria convert nitrates back into nitrogen gas, returning it to the atmosphere..

V. THE PHOSPHORUS CYCLE The movement of phosphorus through rocks, soil, and living organisms. Unlike other cycles, it does not involve the atmosphere. 1. Weathering: Rocks containing phosphate break down over time. 2. Phosphorus Intake: Plants absorb phosphate from the soil through their roots. 3. Food Chain: Animals eat plants to gain phosphorus for organic compounds (like DNA). 4. Return to Ecosystem: Phosphorus returns to the soil/water when organisms die or produce waste. VI. THE SULFUR CYCLE • What is Sulfur? A pale yellow substance that produces a strong, unpleasant smell when burned. It is an essential element for life and is used widely in medicine and industry. • The Cycle: Sulfur moves between the weathering of rocks, volcanic eruptions, and biological processes..