SCP-GENELECT2 - EDITED (2) PDF - St. John Paul II College of Davao Past Paper

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St. John Paul II College of Davao

St. John Paul II College of Davao

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terrestrial ecosystems biology ecology environmental science

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This document is a past paper from St. John Paul II College of Davao, covering the world's major terrestrial ecosystems, including deserts, grasslands, and forests. It explores the differences in climate and vegetation across these ecosystems and how human activities impact them. It discusses the concept of biomes and the three main types of deserts.

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ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Y...

ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Week 7 Lesson Title The World’s Major Terrestrial Ecosystems Learning Determine the world’s major terrestrial Outcome(s) ecosystems; Determine the different human activities affecting the major terrestrial ecosystems of the world. LEARNING INTENT! Terms to Ponder Biomes—large terrestrial regions, each characterized by a particular type of climate and a certain combination of dominant plant life. Desert, annual precipitation is low and often scattered unevenly throughout the year. Grasslands occur primarily in the interiors of continents in areas that are too moist for deserts to form and too dry for forests to grow. Forests are lands that are dominated by trees. Essential Content WHAT ARE THE WORLD’S MAJOR TERRESTRIAL ECOSYSTEMS CONCEPT A. Differences in long-term average annual precipitation and temperature lead to the formation of tropical, temperate, and cold deserts, grasslands, and forests, and largely determine their locations. CONCEPT B. Human activities are disrupting ecosystem and economic services provided by many of the earth’s deserts, grasslands, forests, and mountains. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Climate Helps to Determine Where Terrestrial Organisms Can Live Differences in climate help to explain why one area of the earth’s land surface is a desert, another a grassland, and another a forest. Different combinations of varying average annual precipitation and temperatures, along with global air circulation patterns and ocean currents, lead to the formation of tropical (hot), temperate (moderate), and polar (cold) deserts, grasslands, and forests(Concept A). SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Climate and vegetation vary according to latitude and also according to elevation, or height above sea level. If you climb a tall mountain, from its base to its summit, you can observe changes in plant life similar to those you would encounter in traveling from the equator to the earth’s northern polar region. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Biomes—large terrestrial regions, each characterized by a particular type of climate and a certain combination of dominant plant life. The variety of terrestrial biomes and aquatic systems is one of the four components of the earth’s biodiversity—a vital part of the earth’s natural capital. Biomes are shown with sharp boundaries, and each biome is covered with one general type of vegetation. In reality, biomes are not uniform. They consist of a mosaic of patches, each with somewhat different biological communities but with similarities typical of the biome. These patches occur primarily because of the irregular distribution of the resources needed by plants and animals and because human activities have removed or altered the natural vegetation in many areas. There are also differences along the transition zone (called the ecotone) between two different ecosystems or biomes. This zone contains habitats that are common to both ecosystems along with other habitats that are unique to the transition zone. This results in the edge effect, or the tendency for a transition zone between two different ecosystems to have greater species diversity and a higher density of organisms than are found in either of the individual ecosystems. There Are Three Major Types of Deserts In a desert, annual precipitation is low and often scattered unevenly throughout the year. During the day, the baking sun warms the ground and evaporates water from plant leaves and from the soil. But at night, most of the heat stored in the ground radiates quickly into the atmosphere. This explains why in a desert, you may roast during the day but shiver at night. A combination of low rainfall and varying average temperatures creates a variety of desert types—tropical, temperate, and cold. Tropical deserts such as the Sahara and the Namib of Africa are hot and dry most of the year. They have few plants and a hard, windblown surface strewn with rocks and sand. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached In temperate deserts, daytime temperatures are high in summer and low in winter and there is more precipitation than in tropical deserts. The sparse vegetation consists mostly of widely dispersed, drought-resistant shrubs and cacti or other succulents adapted to the dry conditions and temperature variations. In cold deserts such as the Gobi Desert in Mongolia, vegetation is sparse. Winters are cold, summers are warm or hot, and precipitation is low. In all types of deserts, plants and animals have evolved adaptations that help them to stay cool and to get enough water to survive. Desert ecosystems are fragile because they have slow plant growth, low species diversity, slow nutrient cycling (due to low bacterial activity in the soils), and very little water. It can take decades to centuries for their soils to recover from disturbances such as off-road vehicle traffic, which can also destroy the habitats for a variety of animal species that live underground. The lack of vegetation, especially in tropical and polar deserts, also makes them vulnerable to heavy wind erosion from sandstorms. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached There Are Three Major Types of Grasslands Grasslands occur primarily in the interiors of continents in areas that are too moist for deserts to form and too dry for forests to grow. Grasslands persist because of a combination of seasonal drought, grazing by large herbivores, and occasional fires—all of which keep shrubs and trees from growing in large numbers. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached The three main types of grassland—tropical, temperate, and cold (arctic tundra)—result from combinations of low average precipitation and varying average temperatures (Concept A). One type of tropical grassland, called a savanna, contains widely scattered clumps of trees. This biome usually has warm temperatures year-round and alternating dry and wet seasons. Tropical savannas in East Africa are home to grazing (primarily grass-eating) and browsing (twig- and leaf-nibbling) hoofed animals, including wildebeests, gazelles, zebras, giraffes, and antelopes, as well as their predators such as lions, hyenas, and humans. Herds of these grazing and browsing animals migrate to find water and food in response to seasonal and year-to-year variations in rainfall and food availability. Savanna plants, like those in deserts, are adapted to survive drought and extreme heat; many have deep roots that can tap into groundwater. In a temperate grassland, winters can be bitterly cold, summers are hot and dry, and annual precipitation is fairly sparse and falls unevenly throughout the year. Because the aboveground parts of most of the grasses die and decompose each year, organic matter accumulates to produce deep, fertile topsoil. This topsoil is held in place by a thick network of the grasses’ intertwined roots (unless the topsoil is plowed up, which exposes it to high winds found in these biomes). This biome’s grasses are adapted to periodic droughts and to fires that burn the plant parts above the ground but do not harm the roots, from which new grass can grow. Many of the world’s natural temperate grasslands have been converted to farmland because their fertile soils are useful for growing crops and grazing cattle. Cold grasslands, or arctic tundra, lie south of the arctic polar ice cap. During most of the year, these treeless plains are bitterly cold, swept by frigid winds, and covered with ice and snow. Winters are long with few hours of daylight, and the scant precipitation falls primarily as snow. Under the snow, this biome is carpeted with a thick, spongy mat of low-growing plants. Trees and tall plants cannot survive in the cold and windy tundra because they would lose too much of their heat. Most of the annual growth of the tundra’s plants occurs during the 7- to 8-week summer when there is daylight almost around the clock. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached One outcome of the extreme cold is the formation of permafrost, underground soil in which captured water stays frozen for more than two consecutive years. During the brief summer, the permafrost layer keeps melted snow and ice from draining into the ground. As a consequence, many shallow lakes, marshes, bogs, ponds, and other seasonal wetlands form when snow and frozen surface soil melt on the waterlogged tundra. Hordes of mosquitoes, black flies, and other insects thrive in these shallow surface pools. They serve as food for large colonies of migratory birds (especially waterfowl) that migrate from the south to nest and breed in the tundra’s summer bogs and ponds. Animals in this biome survive the intense winter cold through adaptations such as thick coats of fur (arctic wolf, arctic fox, and musk oxen) or feathers (snowy owl) and living underground (arctic lemming). In the summer, caribou (often called reindeer) and other types of deer migrate to the tundra to graze on its vegetation. Tundra is a fragile biome. Tundra soils usually are nutrient- poor. Because of the short growing season, tundra soil and vegetation recover very slowly from damage or disturbance. Human activities in the arctic tundra—primarily on and around oil drilling sites, pipelines, mines, and military bases—leave scars that persist for centuries. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached There Are Three Major Types of Forests Forests are lands that are dominated by trees. The three main types of forest—tropical, temperate, and cold (northern coniferous, or boreal)—result from combinations of varying precipitation levels and varying average temperatures (Concept A). SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Tropical rain forests are found near the equator, where hot, moisture-laden air rises and dumps its moisture. These lush forests have year-round, uniformly warm temperatures, high humidity, and almost daily heavy rainfall. This fairly constant warm, wet climate is ideal for a wide variety of plants and animals. Tropical rain forests are dominated by broadleaf evergreen plants, which keep most of their leaves year-round. The tops of the trees form a dense canopy that blocks most light from reaching the forest floor. Many of the plants that do live at the ground level have enormous leaves to capture what little sunlight filters down to them. Some trees are draped with vines (called lianas) that reach for the treetops to gain access to sunlight. In the canopy, the vines grow from one tree to another, providing walkways for many species living there. When a large tree is cut down, its network of lianas can pull down other trees. Tropical rainforests have a very high net primary productivity. They are teeming with life and possess incredible biological diversity. Although tropical rain forests cover only about 2% of the earth’s land surface, ecologists estimate that they contain at least 50% of the known terrestrial plant and animal species. For example, a single tree in these forests may support several thousand different insect species. Plants from tropical rainforests are a source of a variety of chemicals, many of which have been used as blueprints for making most of the world’s prescription drugs. At least half of all tropical rain forests have been destroyed or disturbed by human activities such as farming, and the pace of this destruction and degradation is. Ecologists warn that without strong protective measures, most of these forests, along with their rich biodiversity and other highly valuable ecosystem services, could be gone by the end of this century. The second major type of forest is the temperate deciduous forest. Such forests typically see warm summers, cold winters, and abundant precipitation—rain in summer and snow in winter months. They are dominated by a few species of broadleaf deciduous trees such as oak, hickory, maple, aspen, and birch. Animal species living in these forests include predators such as wolves, foxes, and wildcats. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached They feed on herbivores such as white-tailed deer, squirrels, rabbits, and mice. Warblers, robins, and other bird species live in these forests during the spring and summer, mating and raising their young. In these forests, most of the trees’ leaves, after developing their vibrant colors in the fall, drop off the trees. This allows the trees to survive the cold winters by becoming dormant. Each spring, they sprout new leaves and spend their summers growing and producing until the cold weather returns. Because they have cooler temperatures and fewer decomposers than tropical forests have, these forests also have a slower rate of decomposition. As a result, they accumulate a thick layer of slowly decaying leaf litter, which becomes a storehouse of nutrients. On a global basis, temperate forests have been degraded by various human activities, especially logging and urban expansion, more than any other terrestrial biome. However, within 100 to 200 years, forests of this type that have been cleared can return through secondary ecological succession. Cold, or northern coniferous forests, also called boreal forests or taigas (“TIE-guhs”), are found south of the arctic tundra. In their subarctic, cold, and moist climate, winters are long and extremely cold, with winter sunlight available only 6–8 hours per day in the northernmost taigas. Summers are short, with cool to warm temperatures, and the sun shines as long as 19 hours a day during mid-summer. Most boreal forests are dominated by a few species of coniferous (cone-bearing) evergreen trees or conifers such as spruce, fir, cedar, hemlock, and pine that keep most of their leaves (or needles) year-round. Most of these species have small, needle- shaped, wax-coated leaves that can withstand the intense cold and drought of winter when snow blankets the ground. Plant diversity is low because few species can survive the winters when soil moisture is frozen. Year-round wildlife includes bears, wolves, moose, lynx, and many burrowing rodent species. Caribou spend the winter in taiga and the summer in the arctic. During the brief summer, warblers and other insect-eating birds feed on flies, mosquitoes, and caterpillars. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Humans have disturbed much of the Earth’s Land -AKSM Content References/Search Indicator: Miller, G.T. & Spoolman, S.E. (2016) Environmental Science (15th Ed.) Cengage Learning SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Week 8 Lesson Title The World’s Major types of Marine Aquatic Systems and Freshwater Systems Learning Determine the world’s major types of Outcome(s) marine aquatic systems and freshwater systems; Determine the different human activities affecting them. LEARNING INTENT! Term to Ponder Aquatic life zones saltwater and freshwater portions of the biosphere that can support life. Salinity the amounts of various salts such as sodium chloride dissolved in a given volume of water. Essential Content WHAT ARE THE MAJOR TYPES OF MARINE AQUATIC SYSTEMS AND HOW ARE HUMAN ACTIVITIES AFFECTING THEM? CONCEPT A. Oceans dominate the planet and provide vital ecosystem and economic services that are being disrupted by human activities. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Water Covers Most of the Planet When viewed from outer space, the earth appears as a mostly blue planet with about 71% of its surface covered with ocean water. Although the global ocean is a single and continuous body of saltwater, geographers divide it into five large areas—the Arctic, Atlantic, Pacific, Indian, and Southern Oceans—separated by the continents. Together, the oceans hold almost 98% of the earth’s water. Each of us is connected to, and utterly dependent on, the earth’s global ocean through the water cycle. The aquatic equivalents of biomes are called aquatic life zones—saltwater and freshwater portions of the biosphere that can support life. The distribution of many aquatic organisms is determined largely by the water’s salinity—the amounts of various salts such as sodium chloride dissolved in a given volume of water. As a result, aquatic life zones are classified into two major types: saltwater or marine life zones (oceans and their bays, estuaries, coastal wetlands, shorelines, coral reefs, and mangrove forests) and freshwater life zones (lakes, rivers, streams, and inland wetlands). In most aquatic systems, the key factors determining the types and numbers of organisms found at various depths are water temperature, dissolved oxygen content, availability of food, and availability of light and nutrients required for photosynthesis, such as carbon (as dissolved CO2 gas), nitrogen (as NO3−), and phosphorus (mostly as PO43−). Oceans Provide Vital Ecosystem and Economic Services Oceans provide enormously valuable ecosystem and economic services that help to keep us and other species alive and that support our economies. They are also enormous reservoirs of biodiversity. Marine life is found in three major life zones: the coastal zone, the open sea, and the ocean bottom. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached The coastal zone is the warm, nutrient-rich, shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf (the submerged part of the continents). It makes up less than 10% of the world’s ocean area, but it contains 90% of all marine species and is the site of most large commercial marine fisheries. This zone’s aquatic systems include estuaries, coastal marshes, mangrove forests, and coral reefs. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached An estuary is where a river meets the sea. It is a partially enclosed body of water where seawater mixes with the river’s fresh water, as well as nutrients and pollutants in runoff from the land. Estuaries are associated with coastal wetlands— coastal land areas covered with water all or part of the year. These wetlands, which are some of the earth’s most productive ecosystems include coastal marshes and mangrove forests. Sea-grass beds, another component of coastal marine biodiversity, are underwater ecosystems in shallow coastal waters that host as many as 60 species of grasses and other plants, located along most continental coastlines. These coastal aquatic systems provide important ecosystem and economic services. They help to maintain water quality in tropical coastal zones by filtering toxic pollutants, excess plant nutrients, and sediments, and by absorbing other pollutants. They provide food, habitats, and nursery sites for a variety of aquatic and terrestrial species. They also reduce storm damage and coastal erosion by absorbing waves and storing excess water produced by storms and tsunamis. The Open Sea and the Ocean Floor Host a Variety of Species The sharp increase in water depth at the edge of the continental shelf separates the coastal zone from the vast volume of the ocean called the open sea. This aquatic life zone is divided into three vertical zones, or layers, primarily based on the degree of penetration of sunlight. Temperatures also change with depth and we can use them to define zones of varying species diversity in these layers. The euphotic zone is the brightly lit upper zone, where drifting phytoplankton carries out about 40% of the world’s photosynthetic activity. Large, fast-swimming predatory fishes such as swordfish, sharks, and Bluefin tuna populate the euphotic zone. The bathyal zone is the dimly lit middle zone, which receives little sunlight and therefore does not contain photosynthesizing producers. Zooplankton and smaller fishes, many of which migrate to feed on the surface at night, are found in this zone. The deepest zone, called the abyssal zone, is dark and very cold. There is no sunlight to support photosynthesis, and this zone has little dissolved oxygen. Nevertheless, the deep ocean floor is teeming with life because it contains enough nutrients to support a large number of species. Most organisms in the deep waters and on the ocean floor get their food from showers of dead and decaying SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached organisms—called marine snow—drifting down from upper, more lighted levels of the ocean. Human Activities Are Disrupting and Degrading Marine Ecosystems Certain human activities are disrupting and degrading many of the ecosystem and economic services provided by marine aquatic systems, especially coastal marshes, shorelines, mangrove forests, and coral reefs. WHAT ARE THE MAJOR TYPES OF FRESHWATER SYSTEMS AND HOW ARE HUMAN ACTIVITIES AFFECTING THEM? CONCEPT B. Freshwater lakes, rivers, and wetlands provide important ecosystem and economic services that are being disrupted by human activities. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Water Stands in Some Freshwater Systems and Flows in Others Precipitation that does not sink into the ground or evaporate becomes surface water—freshwater that flows or is stored in bodies of water on the earth’s surface. Freshwater aquatic life zones include standing bodies of fresh water such as lakes, ponds, and inland wetlands, and flowing systems such as streams and rivers. Surface water that flows into such bodies of water is called runoff. A watershed, or drainage basin, is the land area that delivers runoff, sediment, and dissolved substances to a stream, lake, or wetland. Although freshwater systems cover less than 2.2% of the earth’s surface, they provide a number of important ecosystem and economic services. Lakes are large natural bodies of standing freshwater formed when precipitation, runoff, streams, rivers, and groundwater seepage fill depressions in the earth’s surface. Causes of such depressions include glaciation (as in Lake Louise in Alberta, Canada), displacement of the earth’s crust (Lake Nyasa in East Africa), and volcanic activity. A lake’s watershed supplies it with water from rainfall, melting snow, and streams. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Freshwater lakes vary tremendously in size, depth, and nutrient content. Deep lakes normally consist of four distinct zones that are defined by their depth and distance from shore. Ecologists classify lakes according to their nutrient content and primary productivity. Lakes that have a small supply of plant nutrients are called oligotrophic lakes. This type of lake is often deep and can have steep banks. Glaciers and mountain streams supply water to many of these lakes, which usually have crystal-clear water and small populations of phytoplankton and fish species, such as smallmouth bass and trout. Because of their low levels of nutrients, these lakes have a low net primary productivity. Over time, sediments, organic material, and inorganic nutrients wash into most oligotrophic lakes, and plants grow and decompose to form bottom sediments. A lake with a large supply of nutrients is called a eutrophic lake. Such lakes typically are shallow and have murky brown or green water. Because of their high levels of nutrients, these lakes have a high net primary productivity. Human inputs of nutrients through the atmosphere and from urban and agricultural areas within a lake’s watershed can accelerate the eutrophication of the lake. This process, called cultural eutrophication, often puts excessive nutrients into lakes. Most lakes fall somewhere between the two extremes of nutrient enrichment. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Freshwater Streams and Rivers Carry Large Volumes of Water In drainage basins, water accumulates in small streams that join to form rivers, which, collectively, carry huge amounts of water from highlands to lakes and oceans. Typically, a stream flows through three zones: the source zone, which contains headwater streams found in highlands and mountains; the transition zone, which contains wider, lower-elevation streams; and the floodplain zone, which contains rivers that empty into larger rivers or into the ocean. As streams flow downhill, they shape the land through which they pass. Over millions of years, the friction of moving water has leveled mountains and cut deep canyons, and sand, gravel, and soil carried by streams and rivers have been deposited as sediment in low-lying areas. At its mouth, a river may divide into many channels as it flows through its delta—an area at the mouth of a river built up by deposited sediment and often containing estuaries and coastal wetlands. These important forms of natural capital absorb and slow the velocity of floodwaters from coastal storms, hurricanes, and tsunamis and provide habitats for a wide variety of marine life. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached , swamps, and prairie potholes (Freshwater Inland Wetlands Are Vital Sponges Inland wetlands are lands located away from coastal areas that are covered with freshwater all or part of the time—excluding lakes, reservoirs, and streams. They include marshesdepressions carved out by ancient glaciers). Other examples are floodplains, which receive excess water from streams or rivers during heavy rains and floods. Some wetlands are covered with water year-round and others remain under water for only a short time each year. The latter include prairie potholes, floodplain wetlands, and arctic tundra. Inland wetlands provide a number of free ecosystem and economic services, which include: filtering and degrading toxic wastes and pollutants; reducing flooding and erosion by absorbing storm water and releasing it slowly, and by absorbing overflows from streams and lakes; helping to sustain stream flows during dry periods; helping to recharge groundwater aquifers; helping to maintain biodiversity by providing habitats for a variety of species; supplying valuable products such as fishes and shellfish, blueberries, cranberries, and wild rice; and providing recreation for birdwatchers, nature photographers, boaters, anglers, and waterfowl hunters. Human Activities Are Disrupting and Degrading Freshwater Systems Human activities are disrupting and degrading many of the ecosystem and economic services provided by freshwater rivers, lakes, and wetlands in four major ways. First, dams and canals restrict the flows of about 40% of the world’s 237 largest rivers. This alters or destroys terrestrial and aquatic wildlife habitats along these rivers and in their coastal deltas and estuaries by reducing water flow and the flow of sediments to river deltas. Second, flood control dikes built along rivers disconnect the rivers from their floodplains, destroy aquatic habitats, and alter or degrade the functions of adjoining wetlands. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Third, cities and farms add pollutants and excess plant nutrients to nearby streams, rivers, and lakes. For example, runoff of nutrients into a lake causes explosions in the populations of algae and cyanobacteria, which deplete the lake’s dissolved oxygen. Fishes and other species may then die off, which can mean a major loss in biodiversity. Fourth, many inland wetlands have been drained or filled to grow crops or have been covered with concrete, asphalt, and buildings. Many other countries have suffered similar losses. For example, 80% of all inland wetlands in Germany and France have been destroyed. A large number of scientists and other individuals are devoting their lives to understanding aquatic systems and learning how we can use them more sustainably. Content References/Search Indicator: Miller, G.T. & Spoolman, S.E. (2016) Environmental Science (15th Ed.) Cengage Learning SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Week 9 Lesson Title Soil and Its Uses Learning Understand the complex nature of soil; Outcome(s) Identify various soil types; Describe the various layers in a soil profile. LEARNING INTENT! Terms to Ponder Soils are complex mixtures of minerals, water, air, organic matter, and countless organisms that are the decaying remains of once-living things. Soil profile is a series of horizontal layers in the soil that differ in chemical composition, physical properties, particle size, and amount of organic matter, each recognizable layer is known as a horizon. Essential Content WHAT IS SOIL? Soils are complex mixtures of minerals, water, air, organic matter, and countless organisms that are the decaying remains of once-living things. It forms at the surface of land – it is the “skin of the earth.” Soil is capable of supporting plant life and is vital to life on earth. Soil and Land are not the same. Land is the part of the world not covered by the oceans. Soil is a thin covering over the land consisting of a mixture of minerals, organic material, living organisms, air, and water that together support the growth of plant life. The proportions of the soil components vary with different types of soils, but a typical, “good” agricultural soil is about 45 percent mineral, 25 percent air, 25 percent water, and 5 percent organic matter. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached So then, what is dirt? Dirt is what gets on our clothes or under our fingernails. It is soil that is out of place in our world – whether tracked inside by shoes or on our clothes. Dirt is also soil that has lost the characteristics that give it the ability to support life – it is “dead.” Soil performs many critical functions in almost any ecosystem (whether a farm, forest, prairie, marsh, or suburban watershed). There are seven general roles that soils play: 1. Soils serve as media for growth of all kinds of plants. 2. Soils modify the atmosphere by emitting and absorbing gases (carbon dioxide, methane, water vapor, and the like) and dust. 3. Soils provide habitat for animals that live in the soil (such as groundhogs and mice) to organisms (such as bacteria and fungi), that account for most of the living things on Earth. 4. Soils absorb, hold, release, alter, and purify most of the water in terrestrial systems. 5. Soils process recycled nutrients, including carbon, so that living things can use them over and over again. 6. Soils serve as engineering media for construction of foundations, roadbeds, dams and buildings, and preserve or destroy artifacts of human endeavors. 7. Soils act as a living filter to clean water before it moves into an aquifer. Soil Types (Texture) Soil can be categorized into sand, clay, silt, peat, chalk and loam types of soil based on the dominating size of the particles within a soil. Sandy soil Sandy Soil is light, warm, dry and tend to be acidic and low in nutrients. Sandy soils are often known as light soils due to their high proportion of sand and little clay (clay weighs more than sand). These soils have quick water drainage and are easy to work with. They are quicker to warm up in spring than clay soils but tend to dry out in summer and suffer from low nutrients that are washed away by rain. The addition of organic matter can help give plants an additional boost of nutrients by improving the nutrient and water holding capacity of the soil. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Clay Soil Clay Soil is a heavy soil type that benefits from high nutrients. Clay soils remain wet and cold in winter and dry out in summer. These soils are made of over 25 percent clay, and because of the spaces found between clay particles, clay soils hold a high amount of water. Because these soils drain slowly and take longer to warm up in summer, combined with drying out and cracking in summer, they can often test gardeners. Silt Soil Silt Soil is a light and moisture retentive soil type with a high fertility rating. As silt soils compromise of medium sized particles they are well drained and hold moisture well. As the particles are fine, they can be easily compacted and are prone to washing away with rain. By adding organic matter, the silt particles can be bound into more stable clumps. Peat Soil Peat soil is high in organic matter and retains a large amount of moisture. This type of soil is very rarely found in a garden and often imported into a garden to provide an optimum soil base for planting. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Chalk Soil Chalk soil can be either light or heavy but always highly alkaline due to the calcium carbonate or lime within its structure. As these soils are alkaline they will not support the growth of ericaceous plants that require acidic soils to grow. If a chalky soil shows signs of visible white lumps then they can’t be acidified and gardeners should be resigned to only choose plants that prefer an alkaline soil. Loam Soil Loam soil is a mixture of sand, silt and clay that are combined to avoid the negative effects of each type. These soils are fertile, easy to work with and provide good drainage. Depending on their predominant composition they can be either sandy or clay loam. As the soils are a perfect balance of soil particles, they are considered to be a gardener’s best friend, but still benefit from topping up with additional organic matter. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Soil Profile There are different types of soil, each with its own set of characteristics. Dig down deep into any soil, and you’ll see that it is made of layers, or horizons (O, A, E, B, C, R). Put the horizons together, and they form a soil profile. Like a biography, each profile tells a story about the life of a soil. Most soils have three major horizons (A, B, C) and some have an organic horizon (O). SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached The horizons are: O – (humus or organic) Mostly organic matter such as decomposing leaves. The O horizon is thin in some soils, thick in others, and not present at all in others. A - (topsoil) Mostly minerals from parent material with organic matter incorporated. A good material for plants and other organisms to live. E – (eluviated) Leached of clay, minerals, and organic matter, leaving a concentration of sand and silt particles of quartz or other resistant materials – missing in some soils but often found in older soils and forest soils. B – (subsoil) Rich in minerals that leached (moved down) from the A or E horizons and accumulated here. C – (parent material) The deposit at Earth’s surface from which the soil developed. R – (bedrock) A mass of rock such as granite, basalt, quartzite, limestone or sandstone that forms the parent material for some soils – if the bedrock is close enough to the surface to weather. This is not soil and is located under the C horizon. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Soil Erosion Erosion is the wearing away and transportation of soil by water, wind, or ice. Soil erosion takes place everywhere in the world, but some areas are more exposed than others. Erosion occurs wherever grass, bushes, and trees are disappearing. Deforestation and desertification both leave land open to erosion. In deforested areas, water washes down steep, exposed slopes, taking the soil with it. Badly eroded soil has lost all of the topsoil and some of the subsoil and is no longer productive farmland. Most current agricultural practices lose soil faster than it is replaced. Content References/Search Indicator: Enger, E., & Smith, B. (2016). Environmental science: A study of interrelationships, 14th Ed. McGraw-Hill Education. https://www.soils4kids.org/about https://www.soils4teachers.org/soil-horizons/ https://www.ctahr.hawaii.edu/mauisoil/a_profile.aspx https://courses.lumenlearning.com/geo/chapter/reading-soil- horizons-and-profiles/ https://www.boughton.co.uk/products/topsoils/soil-types/ https://www.carlisle.k12.ky.us/userfiles/1044/Classes/6685/040 070.pdf SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Week 10 Lesson Title Climate Change Learning Identify the causes of climate change; Outcome(s) Determine the effects of climate change on the society; Illustrate how the community helps in mitigating the hazards caused by climate change. LEARNING INTENT! Terms to Ponder Climate change refers to the statistically significant changes in climate for continuous period of time Essential Content Climate Change (Serafica et al., 2018) The Intergovernmental Panel on Climate Change (IPCC), a United Nations body that evaluates climate change released its report on global climate change. The report’s important conclusions were the following: the world’s climate has changed significantly over the past century; the significant change has human influence; using climate models and if the trend continues, the global mean surface temperature will increase between 1°C and 3.5°C by 2100. Why should a few degrees of warming be a cause for concern? According to experts, global climate change could have a greater potential to change lives on our planet than anything else except a nuclear war. These changes will also lead to a number of potentially serious consequences. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached But first, what is climate change? Climate change refers to the statistically significant changes in climate for a continuous period of time. Factors that contribute to climate change can be a natural internal processes, external forces, and persistent anthropogenic change in the composition of the atmosphere or in land use. It can also be due to natural occurrences or contributed by acts of human beings. Causes of Climate Change Natural Causes Volcanic Eruptions Volcanic eruptions are one of the natural causes of climate change. When volcanoes erupt, it emits different natural aerosols like carbon dioxide, sulfur dioxides, salt crystals, volcanic ashes or dust, and even microorganisms like bacteria and viruses. The volcanic eruption can cause a cooling effect to the lithosphere because its emitted aerosol can block a certain percentage of solar radiation. This cooling effect can last for one to two years. What happens in violent volcanic eruptions is the release of ash particles in the stratosphere. The volcanic ashes which have sulfur dioxide combine with water vapor. It then forms sulfuric acid and sulfurous aerosol. The sulfurous aerosols then are transported by easterly or westerly winds. Volcanoes located near the equator are more likely to cause global cooling because of the wind pattern. Volcanoes located near to north or south poles are less likely to cause cooling because of pole wind pattern, the sulfurous aerosols are confined in the pole area. There are several recorded major volcanic eruptions that cause climate change. Mount Tambora of Indonesia erupted in 1815. It was considered as the largest known eruption in human history. The eruption caused snowfall in the northeastern United States and Canada. It affected their agricultural lands, losing crops that caused food shortage and increased human mortality. The eruptions of Mount Krakatau of Indonesia in 1883 and Mount Pinatubo of the Philippines in 1991 contributed too to the cold years of planet Earth. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Orbital Changes Earth’s orbit can also cause climate change. This was proposed by Milankovitch theory. The Milankovitch theory states “that as the Earth travels through space around the Sun, cyclical variations in three elements of Earth-Sun geometry combine to produce variations in the amount of solar energy that reaches Earth (Academic Emporia, 2017). The three elements that have cyclic variations are eccentricity, obliquity and precession. Eccentricity is a term used to describe the shape of Earth’s orbit around the Sun. Academic Emporia (2017) states, the eccentricity influences seasonal differences: when Earth is closest to the Sun, it gets more solar radiation. If the perihelion occurs during the winter, the winter is less severe. If a hemisphere has its summer while closest to the sun, summers are relatively warm. Obliquity is the variation of the tilt of Earth’s axis away from the orbital plane. As this tilt changes, the seasons become more exaggerated. The obliquity changes on a cycle taking approximately 40,000 years. Academic Emporia (2017) states “the more tilt means more severe seasons – warmer summers and colder winters; less tilt means less severe seasons – cooler summers and milder winters”. Precession is the change in orientation of Earth’s rotational axis. The precession cycle takes about 19,000 to 23,000 years. Precession is caused by two factors: a wobble of Earth’s axis and a turning around of the elliptical orbit of Earth itself (Academic Emporia, 2017). Obliquity affected the tilt of Earth’ axis, precession affects the direction of Earth’s axis. The change in the axis location changes the dates of perihelion (closest distance from the sun) and aphelion (farthest distance from Sun), and this increase the seasonal contrast in one hemisphere while decreasing it in the other hemisphere. Currently, Earth is closest to the Sun in the Northern Hemisphere, which makes the winters there less Severe (Academic Emporia, 2017). SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Carbon Dioxide Carbon dioxide (CO2) is added when power and heat are produced by burning coal, oil, and other fossil fuels. Carbon dioxide is transparent to sunshine but not visible to infrared (heat) radiation leaving the ground. Carbon dioxide absorbs part of the infrared radiation in the air and returns it to the ground keeping the air near the surface warmer than it would be if the carbon dioxide did not act like a blanket. Doubling the carbon dioxide raises the temperature to 2°C to 3°C. Human Activities Human activities contribute to climate change. The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide gas to the atmosphere. Greenhouse gases and aerosols affect climate by altering incoming solar radiation and outgoing infrared (thermal) radiation that are part of Earth’s energy balance. Changing the atmospheric abundance or properties of these gases and particles can lead to a warming or cooling of the climate system. Since the start of the industrial era (about 1750), the overall effect of human activities on climate has been a warming influence. The human impact on climate during this era greatly exceeds that due to known changes in natural processes, such as solar changes and volcanic eruptions. Human activities result in emissions of four principal greenhouse gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and the halocarbons (a group of gases containing fluorine, chlorine and bromine). These gases accumulate in the atmosphere, causing concentrations to increase with time. The greenhouse gases mentioned are natural gases. However, the high level of these gases in the atmosphere contributes to the greenhouse effect. The increasing amount of these gases is due to human activities. A high level of carbon dioxide comes from fossil fuel use in transportation; and the building, heating, cooling, and manufacture of cement and other goods. Deforestation releases carbon dioxide and reduces its uptake by plants. High methane emission is related to agriculture, natural gas distribution, and landfills. High nitrous oxide is also emitted by human activities such as fertilizer use and fossil fuel burning. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Halocarbon gas concentrations have increased primarily due to human activities. Principal halocarbons include the chlorofluorocarbons which were used extensively as refrigeration agents and in other industrial processes before their presence in the atmosphere was found to cause stratospheric ozone depletion. The abundance of CFC gases is decreasing as a result of international regulations designed to protect the ozone layer (The Encyclopedia of Earth, 2016). Ozone is another greenhouse gas that is naturally produced and destroyed in the atmosphere by chemical reactions. In the troposphere, human activities have increased ozone through the release of gases such as carbon monoxide, hydrocarbons, and nitrogen oxide, which chemically react to produce ozone. Halocarbons released by human activities destroy ozone in the stratosphere and have caused the ozone hole over Antarctica. While water vapor is the most abundant and important greenhouse gas in the atmosphere, human activities have only a small direct influence on the amount of atmospheric water vapor. Indirectly, humans have the potential to affect water vapor substantially by changing climate. For example, a warmer atmosphere contains more water vapor. Human activities also influence water vapor through CH 4 emissions, because CH4 undergoes chemical destruction in the stratosphere, producing a small amount of water vapor, and aerosols, the small particles present in the atmosphere with widely varying sizes, concentrations, and chemical composition. Some aerosols are emitted directly into the atmosphere while others are formed from emitted compounds. Aerosols contain both naturally occurring compounds and those emitted as a result of human activities. Fossil fuel and biomass burning have increased aerosols containing Sulphur compounds, organic compounds, and black carbon (soot). Human activities such as surface mining and industrial processes have increased dust in the atmosphere. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Effects of Climate Change on Society Climate change could cause severe effects on all life forms on our planet. It directly affects the basic elements of people’s lives like water, food, health, use of land, and the environment. Climate change will increase worldwide deaths from malnutrition and heat stress. Vector-borne diseases such as malaria and dengue fever could become more widespread if effective control measures are not in place. Rising sea levels may result in more flooded areas each year with a warming of 3 or 4°C. There will be serious risks and increasing pressures for coastal protection. Content References/Search Indicator: McNamara, D.J., Valverde, V.M., & Beleno III, R. (2018). Science, technology and society. C & E Publishing, Inc. Serafica, J.P.J., Pawilen, G.T., Caslib, B.N., & Alata, E.J.P. (2018). Science, technology and Society. Rex Book Store, Inc. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Week 11 Lesson Title Water and Hydrologic Cycle Learning Determine the properties of water; Outcome(s) Identify water resources; Explain how water is cycled through the hydrologic cycle. LEARNING INTENT! Terms to Ponder Water is a renewable resource that circulates continually between the atmosphere and the Earth’s surface. Hydrologic Cycle. The constant recycling process of water. Essential Content Water Water in its liquid form is the material that makes life possible on Earth. All living organisms are composed of cells that contain at least 60 percent water. Furthermore, their metabolic activities take place in a water solution. Organisms can exist only where they have access to adequate supplies of water. Water is also unique because it has remarkable physical properties. Water molecules are polar; that is, one part of the molecule is slightly positive and the other is slightly negative. Because of this, the water molecules tend to stick together, and they also have a great ability to separate other molecules from each other. Water’s ability to act as a solvent and its capacity to store heat is a direct consequence of its polar nature. These abilities make water extremely valuable for societal and industrial activities. Water dissolves and carries substances ranging from nutrients to industrial and domestic wastes. A glance at any urban sewer will quickly point out the importance of water in dissolving and transporting wastes. Because water heats and cools more slowly than most substances, it is used SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached in large quantities for cooling in electric power generation plants and in other industrial processes. Water’s ability to retain heat also modifies local climatic conditions in areas near large bodies of water. These areas do not have the wide temperature-change characteristic of other areas. For most human as well as some commercial and industrial uses, the quality of the water is as important as its quantity. Water must be substantially free of dissolved salts, plant, animal waste, and bacterial contamination to be suitable for human consumption. The oceans, which cover approximately 70 percent of the Earth’s surface, contain over 97 percent of its water. However, saltwater cannot be consumed by humans or used for many industrial processes. Freshwater is free of the salt found in ocean waters. Of the freshwater found on Earth, only a tiny fraction is available for use. Unpolluted freshwater that is suitable for drinking is known as potable water. The global water supply, by comparison, is finite. Whether it’s in the form of ice, vapor, steam, or liquid, the amount of water on Earth today is about the same as the water that slaked the planet’s thirst a million years ago. Only a very thin slice of that supply is the liquid freshwater that we depend upon for drinking, washing, irrigation, manufacturing, energy, and more. The world’s total water supply is estimated at about 1.38 billion cubic kilometers (333 million cubic miles). Of this, about 97.5 percent is saltwater and about 2.5 percent is freshwater. Most of the freshwater (78 percent) is locked up in glaciers and ice caps, about 21 percent is groundwater in deep sediments or soil, and less than 1 percent is surface water. About 87 percent of surface freshwater is in lakes, 11 percent in wetlands, and 2 percent in rivers. Some areas of the world have abundant freshwater resources, while others have few. In addition, demand is increasing for freshwater for industrial, agricultural, and personal needs. Shortages of potable freshwater throughout the world can also be directly attributed to human abuse in the form of pollution. Water pollution has negatively affected water supplies throughout the world. In many parts of the developing world, safe drinking water is scarce. The World Health Organization estimates that about 25 percent of the world’s people do not have access to safe drinking water. Even in the economically advanced regions of the world, water quality is a major issue. According to the United Nations Environment Programme, 5 million to 10 million deaths occur each year from water-related diseases. The illnesses include cholera, SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached malaria, dengue fever, and dysentery. The United Nations also reports that these illnesses have been increasing over the past decade and that without large economic investments in safe drinking-water supplies, the rate of increase will continue. Water, used by households, agriculture, and industry, is clearly the most important good provided by freshwater systems. Increasing scarcity, competition, and arguments over water in the first quarter of the twenty-first century could dramatically change the way we value and use water and the way we mobilize and manage water resources. Furthermore, changes in the amount of rain from year to year result in periodic droughts for some areas and devastating floods for others. However, rainfall is needed to regenerate freshwater and, therefore, is an important link in the cycling of water. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached The Hydrologic Cycle All water is locked into a constant recycling process called the hydrologic cycle. Two important processes involved in the cycle are the evaporation and condensation of water. Evaporation involves adding energy to molecules of a liquid so that it becomes a gas in which the molecules are farther apart. Condensation is the reverse process in which molecules of gas give up energy, get closer together, and become a liquid. Solar energy provides the energy that causes water to evaporate from the ocean surface, the soil, bodies of fresh water, and the surfaces of plants. The water evaporated from plants comes from two different sources. Some is water that has fallen on plants as rain, dew, or snow. In addition, plants take up water from the soil and transport it to the leaves, where it evaporates. This process is known as evapotranspiration SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached The water vapor in the air moves across the surface of the Earth as the atmosphere circulates. As warm, moist air cools, water droplets form and fall to the land as precipitation. Although some precipitation may simply stay on the surface until it evaporates, most will either sink into the soil or flow downhill or enter streams and rivers, which eventually return the water to the ocean. Surface water that moves across the surface of the land and enters streams and rivers is known as runoff. Water that enters the soil and is not picked up by plant roots moves slowly downward through the spaces in the soil and subsurface material until it reaches an impervious layer of rock. The water that fills the spaces in the substrate is called groundwater. It may be stored for long periods in underground reservoirs. The porous layer that becomes saturated with water is called an aquifer. An aquifer is an underground layer of gravel, sand, or permeable rock that holds groundwater that can be extracted by wells. There are three basic kinds of aquifers: unconfined, semi- confined, and confined. An unconfined aquifer usually occurs near the land’s surface where water enters the aquifer from the land above it. The top of the layer saturated with water is called the water table. The lower boundary of the aquifer is an impervious layer of clay or rock that does not allow water to pass through it. Unconfined aquifers are replenished (recharged) primarily by rain that falls on the ground directly above the aquifer and infiltrates the layers below. The water in such aquifers is at atmospheric pressure and flows in the direction of the water table’s slope, which may or may not be similar to the surface of the land above it. Above the water table and below the land surface is a layer known as the vadose zone (also known as the unsaturated zone or zone of aeration) that is not saturated with water. A confined aquifer is bounded on both the top and bottom by layers that are impervious to water and is saturated with water under greater-than-atmospheric pressure. An impervious confining layer is called an aquiclude. If water can pass in and out of the confining layer, the layer is called an aquitard and the aquifer is known as a semiconfined aquifer. Both confined and semi-confined aquifers are primarily replenished by rain and surface water from a recharge zone (the area where water is added to the aquifer) that may be many kilometers from where the aquifer is tapped for use. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached If the recharge area is at a higher elevation than the place where an aquifer is tapped, water will flow up the pipe until it reaches the same elevation as the recharge area. Such wells are called artesian wells. If the recharge zone is above the elevation of the top of the well pipe, it is called a flowing artesian well because water will flow from the pipe. The nature of the substrate in the aquifer influences the amount of water the aquifer can hold and the rate at which water moves through it. Porosity is a measure of the size and number of the spaces in the substrate. The greater the porosity, the more water it can contain. The rate at which water moves through an aquifer is determined by the size of the pores, the degree to which they are connected, and any cracks or channels present in the substrate. The rate at which the water moves through the aquifer determines how rapidly water can be pumped from a well per minute. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached Content References/Search Indicator: Enger, E., & Smith, B. (2016). Environmental science: A study of interrelationships, 14th Ed. McGraw-Hill Education. SCP-GENELECT 2 | 1 ST. JOHN PAUL II COLLEGE OF DAVAO EDUCATION DEPARTMENT Physically Detached Yet Academically Attached SCP-GENELECT 2 | 1

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