ECOLOGYEcology is the study of the interactions of organisms with one another and with their environment. An environment is composed of both biotic and abiotic factors which influence the survival and behaviors of organisms. ______________________ are the living and once living parts of an environment (i.e. plants, animals, dead organisms). _______________________ are the nonliving parts of the environment (i.e. air, water, rocks, sand, light & temperature).

_________________ - an individual living thing. A species is a group of organisms that can mate to produce fertile offspring. Every organism is a member of a species.

_________________ – all the members of the same species that LIVE in the same place at the same time

_________________ – a group of various species that live in the same place and interact with each other. It’s only made of biotic components.

_________________ - are all of the organisms living in an area together with their physical environment.

_________________ - are large climatic region that contains a number of smaller ecosystems. Biomes may exist in more than one location and are distinguished by plants and animals.

________________ - the thin layer of Earth and the atmosphere that supports life.

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All organisms live in particular place called ___________________. Every habitat has specific biotic and abiotic factors that the organism living there needs to survive. Organisms tend to be very well suited to their natural habitats due to adaptations, inherited traits, which increase their chance of survival and reproduction. Adaptations such as: camouflage (blending in with surroundings), mimicry (looking or sounding like another organism), chemical defenses (venom, ink, sprays), body parts (claws, beaks, armor plates) and unique methods of obtaining food, defending oneself, hibernation, migration, etc..________________________ refers to the unique role a species has in its environment – how it meets its needs for food and shelter, how it survives, and how it reproduces. A niche includes the species’ habitat, the environmental factors necessary for the species’ survival and all the species interactions with other organisms. For example: A tree frog in a Brazilian rainforest can only survive if temperatures and humidity stay within a certain range. It also needs access to a certain amount and type of food. It must avoid becoming food for predators. The sum of these conditions is the frog’s niche.

HABITAT & NICHE

POPULATION ECOLOGYPopulations may be described in terms of size, density and dispersion. These properties can be used to describe populations and to predict changes within them. Population sizes can be determined by factors such as births, death, immigration and emigration. r = (b - d) + (i - e)

_________________________ is a measurement of the number of individuals living in a specified habitat. Environmental influences can alter population density and distribution, age structure and variations in population size.

Population dispersion refers to the relative distribution of its individuals within an area. Dispersion can occur in patterns:1. _______________ - individuals aggregate in patches;

influenced by resource availability & behavior2. _______________ - individuals are evenly distributed;

influenced by social interactions such as territoriality3. _______________ - the position of each individual is

independent of other individuals

Populations usually stay about the same size from year to year because various factors kill many individuals before they can reproduce. A species’ ______________________ is the fastest rate at which its population can reproduce. This rate is limited by an organism’s reproductive potential which is the maximum number of offspring that each member of the population can produce. Reproductive potential increases when individuals produce more offspring at a time, reproduce more often, and reproduce earlier in life.

Population Growth Patterns: Exponential growth – occurs when populations have plenty of food, space and have little or no competition or predators. Populations rapidly increase due to an abundance of resources. There are _____________________________. (J-shaped curve) This growth is not sustainable – short lived in nature. Natural

conditions are neither ideal nor constant; populations cannot grow forever and rarely grow at their reproductive potential. Resources are used up or the environment changes.

Logistic growth – populations are ____________________ by environmental factors and tend to attain equilibrium in size which is determined by available resources. (S-shaped curve)

______________________________ of a particular species is the maximum population that the ecosystem can support indefinitely. A population may increase beyond this number, but it cannot stay at this increased size due to resource availability. Because ecosystems change, carrying capacity is difficult to

calculate exactly --- it’s a theoretical limit. A species reaches it carrying capacity when it consumes a

natural resource at the same rate at which the ecosystem produces the resources. The limited resource determines the carrying capacity for a species at a particular time.

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LIMITING FACTORS - Factors that prevent a population from reaching its biotic potential. Population size can be limited in ways that may or may not depend on the density of the population. 1. ________________________________ - Factors that have an increasing effect as the

population increase. As organisms crowd together, these factors cause more damage and spread faster in larger populations. resource availability, predation, disease, competition, parasitism, stress due to

overcrowding2. ________________________________ – Factors that affect any population, regardless of

density; NOT influenced by population size. weather, natural disasters, human activities, adaptations & behaviors of organisms

COMMUNITY ECOLOGYSpecies interactions are based on whether each species causes benefit or harm to the other species in a given relationship. Each interaction affects evolution, persistence of a species and the overall diversity of life. Organisms have evolved together and therefore adjusted to one another. An organism’s niche and habitat are important factors in these interactions.

_______________________ – A relationship in which different individuals or populations attempt to use the same limited resources. Each individual has less access to the resource & is harmed by the competition. Members of the same species must compete with each other because they require the same

resource – they occupy the same niche. When members of different species compete, their niches overlap, which means that both species use some of the same resources in a habitat.

Competitive Exclusive Principle - Two species that have exactly the same requirements cannot coexist in exactly the same habitat. Otherwise, competition will occur.

Indirect competition – Species compete even if they never come into direct contact with each other. (i.e. Insects feeding on same plant at different times.)

_______________________ – The act of one organism (predator) feeding on another organism (prey). Most organisms are vulnerable to predation, so there are strong selective pressures for adaptations that serve as defenses against predators. Adaptations that can enhance survival of prey include camouflage, warning coloration, mimicry and protective covering. Some predators eat only specific types of prey. In

this close relationship, the sizes of each population tend to increase and decrease in linked patterns. However, many predators will feed on whichever type of prey is easiest to capture.

Symbiosis – A relationship in which two species live in close association. These species may evolve adaptations that reduce the harm or improve the benefit of the relationship. _____________________ – An organism that lives in or on another organism (host) and

feeds on it. Parasites usually do not kill their hosts, but weakens or develops a disease. _____________________– Two species provide a benefit and depend on each other for

survival. ______________________ – A relationship in which one species benefits and the other

species is neither harmed nor helped.

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______________________________________ is composed of species best adapted to conditions in an area and has reached equilibrium. The ecosystem is established and changes are slow.

ECOSYSTEMSChanges in Ecosystems - Ecological succession is a gradual __________________________ and replacement of some or all of the species in a community. Ecological succession may take hundreds or thousands of years. Each new community that arises makes it harder for the previous community to survive, because of competition for resources. Succession provides opportunities for new resources and niches to become available for the next community.

__________________________________ – The initial establishment and development of an ecosystem. Begins in a place without any soil and no previous life exists. Starts with the arrival of living things such as lichen, moss or bacteria that do not need soil to survive…these first organisms are called ________________________. Soil starts to form as pioneer species and the forces of weather and erosion help break down rocks into smaller pieces. Pioneer species decompose and add small amounts of organic matter to the rock to make soil. Simple plants like mosses and ferns grow in the new soil. When these plants decompose, it adds more organic material. The soil layer thickens and other plants begin to take over. These plants die, and they add more nutrients to the soil. Shrubs and trees can survive now. Insects, small birds, and mammals have begun to move in. What was once bare rock now supports a variety of life.

Primary succession can occur on new islands created by volcanic eruptions, in areas exposed when a glacier retreats, sand dunes or any other surface that has not previously supported life. Slow process because it begins with no soil.

__________________________________ – The reestablishment of an ecosystem that contains soil and vegetation of a previous biological community ---- ecosystems have been disturbed or disrupted by humans or animals, or by natural processes such as storms, floods, fires, earthquakes, etc. These disturbances open up opportunities for new niches to be established during the rebuilding of the area. The soil remains and the process is faster than primary

succession.

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Remember: Energy can neither be created nor destroyed; it can only be changed from one form to another. There is always some loss of energy usually in the form of heat during the change.

Energy Flow in Ecosystems - The primary source of energy for an ecosystem is the sun. Photosynthetic organisms change light energy from the sun into carbohydrates. As organisms consume food and use energy from carbohydrates, the energy travels from one organism to another. When an animal eats a plant, some energy is transferred from the plant to the animal. Organisms use this energy to move, grow and reproduce.

Because plants make their own food, they are called __________________ or producers. A producer is an organism that can make carbohydrates (organic compounds) from the sun’s energy or inorganic compounds. (i.e. Bacteria in deep-ocean vents use hydrogen sulfide, an inorganic compound, as the energy source to perform chemosynthesis).

A ___________________ or consumer is an organism that eats other organisms or organic matter instead of producing its own nutrients. Consumers get their energy indirectly by eating producers or other consumers.

Each time an organism eats another organism, an energy transfer occurs. Studying the paths of energy between organisms can tell us how much energy is transferred and which organisms depend on other organisms for survival in an ecosystem.

A food chain is a sequence in which energy is transferred from one organism to the next as each organism eats another organism.Energy flow in an ecosystem is more complex than energy flow in a simple chain. So a food web includes multiple food chains linked together to show many feeding relationships in an ecosystem.

Each step in the transfer of energy through a food chain or food web is known as a _______________________________. Energy flows from one trophic level to the next --- in ONE direction from the producer to the consumer.

Find one food chain in the web --- label the trophic levels.

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Types of ConsumersHerbivore eats producersCarnivore eats consumersOmnivore eats consumers and producersDecomposers(fungi & bacteria)

break down dead organisms and returns nutrients to the soil, water and air

CARBON CYCLE

WATER CYCLE

Energy decreasesBiomass decreasesPopulation decreases

Each time energy is transferred, some of the energy is lost as heat. Therefore, less energy is available to organisms at higher trophic levels. One way to visualize this is with an energy pyramid. When energy is used, about ________ of the energy

at each trophic level is _________________ _______________________ and dispersed into the environment. Only about _______ of energy is stored in the animal’s body as fat or as tissue and is the amount of energy ___________________ to the next trophic level.

Decreasing amounts of energy at each trophic level affects the number of organisms at each level and limits the number of trophic levels in an ecosystem. Big predators are rare because a lot more energy is required to support a single predator than a single herbivore. Many ecosystems do not have enough energy to support a large population of predators.

____________________ is the total amount of living tissue in each tropic level --- lower level has the greatest amount.

Matter Cycles in Ecosystems - Matter is recycled within and between ecosystems. Biogeochemical cycles pass the same molecules around within the biosphere.

Water Cycleo _____________________ returns H2O back into

the atmosphere which leads to condensation in the clouds.

o Precipitation sends water back to Earth’s surface. Most of the surface water is runoff hat returns back into a body of water, but some water seeps into the soil for groundwater or for plants to use.

Carbon Cycleo Carbon is an essential component of fats, proteins and carbohydrates, which make up all

organisms. o Carbon cycles between the process of _________________ and ______________________.

Photosynthesis removes CO2 and respiration releases CO2. o Carbon is converted into carbonates which make up bones and shells. Over millions of years,

______________________ have produced large formations of limestone rocks resulting in one of the largest carbon reservoirs on Earth.

o Some carbohydrates in organisms are converted to fats that store energy. When an organism dies and ____________________ occurs, this carbon is returned to the soil and air. Over millions of years, these deposits will form coal, oil, and natural gas (fossil fuels). __________ ______________________ release carbon dioxide back into the atmosphere.

How humans affect the Carbon Cycle?

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NITROGEN CYCLE

PHOSPHORUS CYCLE

Cars, factories and power plants rely on fossil fuels to operate. Each year, about 6 billion metric tons of carbon is released into the atmosphere as CO2 by the burning of fossil fuels and the burning of wood in forest fires. As a result, the amount of CO2 levels in the atmosphere has steadily increased. Increased levels of CO2 may contribute to global warming, which is an overall increase in temperature of the Earth.

Nitrogen CycleAll organisms need nitrogen to build proteins, which are used to build new cells. However, most organisms CAN NOT use atmospheric nitrogen, which makes up 78% of atmospheric gases. It must be altered or fixed before organisms can use it. Nitrogen-fixing bacteria convert atmospheric nitrogen into ammonia or nitrate, a usable form of nitrogen. o Nitrogen-fixing bacteria live in the soil or in nodules on the roots of plants called legumes. The

bacteria use sugars provided by the legumes to produce nitrates. The excess nitrogen fixed by the bacteria is released into the soil. _____________________ – The process of bacteria converting ammonia (NH3) (toxic to plants) to nitrites (toxic to plants) (NO2-) and then finally to nitrates (NO3-).

o Animals get nitrogen by eating plants or other animals. Decomposers in the soil break down waste or decaying organisms and return the nitrogen to the soil.

o __________________________ - The process of releasing fixed nitrogen back to atmospheric nitrogen gas. Denitrifying bacteria transform nitrogen in the soil back into atmospheric nitrogen gas.

How humans affect the Nitrogen Cycle?Humans have impacted this cycle due to agricultural fertilization, burning of fossil fuels, wastewater etc. Excessive nitrogen contributes to acid precipitation, contamination of water, removal of nitrogen from topsoil, and destruction of plant through the release of excess nitrogen.

Phosphorus Cycle The phosphorus cycles fairly slowly through the earth’s water, soil and living organisms. It is an essential element for life, in molecules of DNA and ATP, and often is a limiting nutrient for plant growth. Most phosphorus is stored in the Earth’s ______________________ and is released to water via erosion and weathering. Phosphorus does NOT exist as a gas!! o When rocks erode, small amounts of phosphorus dissolve in soil and water. When organisms

excrete waste or decompose, phosphorus is added in soil and water. o Plants take up phosphorus in aquatic and terrestrial ecosystems and animals eat the plants;

returning the phosphorus to the soil via urine, feces, and death.

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Excessive amounts of phosphorus and nitrogen in aquatic ecosystems can cause an algal bloom, overgrowth of algae. Algal blooms can deplete nutrients such as oxygen from the ecosystem.

How humans affect the Phosphorus Cycle?Humans remove large amounts of phosphate from the earth through mining to make fertilizers, reduce phosphorus in tropical soils by clearing forests and then we add excess phosphates into aquatic systems. Phosphorus disrupts aquatic systems through runoff of animal wastes, fertilizers and discharges from sewage treatment systems.

BIOMESTerrestrial biomes are characterized by specific type of climate and certain types of plants and animal communities. Climate refers to the average weather conditions such as temperature, precipitation, humidity, and winds in an area. The climate zones are caused by differences in latitude and the angle the sun hits the Earth. The unequal heating causes winds and ocean currents which transport heat throughout the biosphere. Topography interferes with the movement of the air masses.

Tropical Rain Forest – It is the most widespread biome and has the greatest diversity of plants, animals and other organisms. This biome is located at the equator and helps to regulate world climate by playing a vital role in the nitrogen, oxygen and carbon cycles.

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Tropical rain forests are always humid and maintain a relatively constant warm temperature year-round. The soil is nutrient poor because the nutrients are within plants. Decomposers break down organic matter and return nutrients to the soil, but plants quickly absorb the nutrients. Layers of the forest: Emergent layer – tallest trees; Canopy – epiphytes grow to help support life; Understory – plants adapted to shade grow here.

Temperate Deciduous Forest – These forests are generally located between 30o-50oN latitudes. The range of temperatures can be extreme with the growing seasons lasting only 4 to 6

months. Plants are adapted to survive seasonal changes. Trees are predominately are broad, flat leaf which fall during the fall. Decomposition of organic matter occurs slowly which causes nutrient rich soil. Animals usually hibernate or migrate during the winter months.

Taiga – This northern coniferous forest stretches in a band across the Northern Hemisphere. Winters are long (6-10 months) and have average temperatures below freezing. Plant growth

is abundant during summer months because of nearly constant daylight and larger amounts of precipitation. Mostly conifers trees grow which have needle-like leaves and seeds that develop in cones. The shape of the leaves and their cuticle prevents the tree from losing too much water especially important when ground is frozen and the roots cannot replace lost water by absorbing more from the soil. Conifer needles contain substances that make the soil acidic when the needles fall. Most plants cannot grow in acidic soil, which is one reason the forest floor has few plants. Soil forms very slowly because the climate and acidity of fallen leaves slows decomposition. This biome has many lakes and swamps which attract birds that feed on aquatic organisms. Animals usually hibernate or migrate during winter months.

Threats to the FOREST biomes - Deforestation reduces the amount of water that is absorbed by plants after it rains. As

deforestation increases, an increase in flooding is likely to occur. Tropical rain forest once covered about 20% of Earth, but today it only covers about 7%.

Forests are cleared for logging operations, agriculture or oil exploration. Habitat destruction usually results in species endangerment or extinction.

Savannas – Grassland found in Africa, western India, northern Australia and South America. A tropical biome that is dominated by grasses, shrubs and small trees. Rain falls mainly during

the wet season, which last for only a few months of the year. Because most rain falls during the wet season, plants must be able to survive prolonged periods without water. During the dry season, plants lose their leaves or die down to the ground. Many plants have horizontal root systems so they can draw water from a larger area. Most plants have vertical leaves to reduce water loss and thorns to keep herbivores away. Grazing herbivores have adopted a migratory way of life and follow the rains. Many animals give birth during the rainy season when food is abundant and the young are more likely to survive.

Temperate Grassland – This grassland covers a large area of the interior of continents, where there is moderate rainfall, but still too little for trees to grow. This includes the prairies in North America, the steppes of Asia, the veldt in South Africa and the pampas in South America. Vegetation consists of mainly grasses and wildflowers. Near the banks of streams, the soil

contains more water so shrubs and trees can grow. The root systems form dense layers that survive drought and fire. Grasslands are highly productive because of their fertile soil. The summer is hot and the winter is cold, so the plants die back to their roots in winter. Low temperatures in the winter slow decomposition and organic matter accumulate in the soil

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making it the most fertile soil in the world. Grazing animals (herbivores) and burrowing animals are predominately found.

Threats – Farming and overgrazing has caused soil erosion and depletion of nutrients from the soil making the soil less fertile.

Chaparral – Temperate shrub land that is found in areas that have moderately dry, coastal climates with little to no rainfall. Most plants are low-lying, evergreen shrubs and small trees that tend to grow in small

patches. These plants have small, leathery leaves that retain water. The leaves contain natural oils that promote burning, which is an advantage because natural fires destroy trees that might compete with chaparral plants for light and space. These plants are well adapted to fire and can re-sprout from small bits of surviving plant tissue. Common adaptation of animals is camouflage, which is shape and coloring that allows animals to blend into its environment.

Threats – Human development is the greatest threat.

Deserts – Areas that have widely scattered vegetation and receive very little rain. Even in hot deserts near the equator, there is little insulating moisture in the air that temperatures change rapidly in a 24-hour period. The temperature may go from 40oC in the day to near freezing at night. Deserts are often located near mountain ranges, which block the passage of rain clouds. Plants have adaptations for obtaining and conserving water, which allow the plants to live in

dry desert conditions. Succulents are plants that have thick, fleshy stems and leaves that store water. Their leaves have a waxy coating that prevents water loss. Sharp spines protect the plants from animals. Rainfall rarely penetrates deep into the soil, so many plant roots spread out just under the surface to absorb as much rain as possible. Many shrubs drop their leaves during dry periods and grow new leaves when it rains again. When conditions are too dry, some plants die and drop seeds that stay dormant until the next rainfall. Reptiles have thick, scaly skin that prevents water loss. Amphibians survive summers by estivating – burying themselves in the ground and sleeping during the dry season. Desert insects and spiders are covered with body armor that helps retain water. Most desert animals are nocturnal which means they are active mainly at night when the air is cooler.

Tundra – In northern arctic regions, the winter is too cold and dry to permit the growth of trees. The deeper layers of soil called permafrost are permanently frozen. In the summer the thin topsoil layer thaws and becomes a moist, spongy wet area ideal for insects and birds. Moss and lichen which can grow without soil cover vast areas of rock. The soil is thin, so

plants have wide, shallow roots to anchor them against the icy winds. Most plants are short and grow close to the ground to avoid wind and help absorb heat from the sunlit soil during the summer. Migratory birds and other animals are present during the summer. Some animals burrow underground during the winter, but are still active. Many animals that live in the tundra year-round lose their brown fur and grow white fur to camouflage them in the winter snow. These animals are also extremely well insulated.

Threats – It’s the most fragile biome and is easily disrupted. Because conditions are so extreme, the lands is easily damaged and slow to recover. Until recently, the tundra was undisturbed by humans, but oil exploration, extraction and transport has disrupted the habitats of plants and animals. Pollution caused by spills of oil or other toxic materials may poison the food and water sources of organisms.

Aquatic ecosystems are determined mainly by water’s salinity – the amount of dissolved salts. Freshwater ecosystems include waters of lakes, ponds, rivers, streams and wetlands. Marine

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ecosystems include the diverse coastal areas of marshes, swamps, coral reefs and oceans. Factors such as temperature, sunlight, oxygen and nutrients determine which organisms live in which areas of the water. Zooplankton and phytoplankton form masses of microscopic organisms that float or drift freely in the water.

Lakes and Ponds – In a nutrient-rich littoral zone near the shore, aquatic life can be diverse and abundant. Plants are rooted in mud underwater and their upper leaves and stems emerge above the water. In the open water, sunlight near the surface support drifting phytoplankton. Benthic zone is the bottom which is inhabited by decomposers, insect larvae and clams. Eutrophication is an increase in the amount of nutrients in an aquatic ecosystem. As the

amount of plants and algae grows, the number of decomposers increases. These bacteria use oxygen dissolved in the water. The reduced amount of oxygen kills oxygen-loving organisms and the lake becomes eutrophic over time. This process can be accelerated due to runoff.

Freshwater Wetlands – Land is covered with freshwater for at least part of the year such as marshes and swamps. Most freshwater wetlands in the U.S. are located in the Southeast. Wetlands act as filters because they absorb and remove pollutants from the water that flows

through them. Wetlands improve the water quality of lakes, rivers and reservoirs downstream. They control flooding by absorbing extra water when rivers overflow. Many game fish use wetlands for feeding and spawning. These areas provide habitats for wildlife.

Human Impact – Wetlands were previously considered to be wastelands that provide breeding grounds for disease-carrying insects. Therefore, many have been drained, filled and cleared for development. For example, the Florida Everglades once covered 8 million acres, but now covers less than 2 million acres. The government now protects many wetlands and prohibits their destruction.

Rivers – Many rivers originate from the snow melt in mountains. At its headwaters, a river is usually cold, full of oxygen and runs swiftly through a shallow riverbed. As the river flows down a mountain, it becomes warmer, wider, slower, contains more vegetation and less oxygen. A river changes with the land and the climate through which it flows. Runoff washes nutrients and sediments into rivers affecting the growth and health of organisms. Near the headwaters, moss anchor themselves to rocks using root-like structures called

rhizoids. Trout and minnows are adapted to the cold, oxygen-rich headwaters. Downstream the plants set roots into the sediment and other species of fish live in the calmer waters.

Human Impact – People draw water to use in homes and manufacturing. Sewage and garbage have been disposed of in rivers resulting in toxins that kill organisms and make the organisms unsuitable for eating. Runoff of pesticides and other poisons accumulate in sediments. Dams also alter ecosystems in rivers.

Coastal Wetlands – Coastal lands covered by salt water for all or part of the time. Coastal wetlands provide habitat and nesting areas for fish and other wildlife. Coastal wetlands absorb excess rain, protect areas from flooding, filter out pollutants and sediments and provide a recreational area for humans. Many coastal wetlands form in estuaries where fresh water rivers mix with the salt water from

the ocean. As the two bodies meet, currents form and cause mineral-rich mud and dissolved nutrients to fall to the bottom. These nutrients become available and in shallow areas, marsh grass will grow in the mud. Estuaries constantly receive fresh nutrients from the river. The surrounding land protects estuaries from the force of ocean waves. Estuaries support many marine organisms that are able to tolerate variations in salinity when tides go in and out. Estuaries provide protective harbors, access to the ocean and connection to a river.

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Threats to Estuaries – In populated areas, estuaries were often used as solid waste landfills which were filled and used as building sites. Pollutants such as sewage, industrial waste and agricultural runoff damage the ecosystem. Most pollutants are broken down over time, but estuaries cannot cope with the excessive amounts produced by humans.

Salt Marshes – In estuaries, where river deposit their load of mineral-rich mud, salt marshes form. The marsh supports a community of clams, fish and aquatic birds. It serves as a nursery for many species. It absorbs pollutants and protects inland areas.

Mangrove Swamps – Mangroves are small trees adapted for growing in shallow salt water (i.e. above-ground root systems for support). Dense growths of mangrove trees in swampy areas form mangrove swamps that grow in tropical and subtropical zones. These areas protect the coastline from erosion and reduce the damage from storms.

Rocky and Sandy Shores – Rocky shores have more plant and animal species than sandy shores do. The rocks anchor seaweed and many animals live on it. Life on sandy shores is abundant in the water, the sand and in sediments. Animals in these areas are adapted to the effects of drying and exposure at low tide. Barrier islands often run parallel to sandy shores and help protect the mainland and coastal wetlands from storms and ocean waves.

Coral Reefs – Reefs are limestone ridges built by tiny coral animals called polyps and the algae that live inside them. Coral polyps secrete skeletons of limestone (calcium carbonate) which slowly accumulates and form the reefs. Thousands of species live in the reefs making it one of the most diverse ecosystems. Reefs are found in shallow, clear tropical seas. Threats – If the water is too hot or cold for too long or if it is too polluted, muddy or high in

nutrients, the algae that live in the coral will leave or die. As a result, the coral turn white causing coral bleaching. If bleaching occurs often or long enough, the animals and reef will die. About 50% of the world’s coral reefs are now in danger of destruction. In addition, global warming, oil spills and polluting runoff have been linked to the destruction of coral reefs. Overfishing upsets the balance of reef ecosystem by devastating fish populations. Because coral reefs grow slowly, a reef may not be able to repair itself when stressed or destroyed.

Oceans – Much of ocean’s life is concentrated in the shallow, coastal waters were sunlight penetrates to the bottom and rivers wash nutrients form the land. Seaweed and algae grow anchored to rocks and phytoplankton drift on the surface. In the open ocean, phytoplankton grows only in areas where there is enough light and nutrients. Zooplankton and other herbivores feed and live in areas with more plant life. Fish and marine mammals feed on these herbivores. Deep ocean water organisms depend on food that drifts down from above. Threats – Pollution from agricultural runoff and industrial waste may cause algal blooms to

occur depleting the nutrients from the water. Overfishing and certain fishing methods have reduced the number of ocean animals.

Arctic and Antarctic Ecosystems – The Arctic Ocean is rich in nutrients from the surrounding land masses. It supports large populations of plankton which provide food for other organisms. The Antarctic is the only continent never colonized by humans. Even during the summer, only a few plants grow at rocky edges. As in the Arctic, plankton forms the basis of the food web and support a large numbers of organisms.

BIOSPHERE – Environmental IssueWhether a resource is "renewable" or "nonrenewable" is about how long nature takes to renew it.

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Renewable resources can ___________________ and are ___________________. However, a renewable resource is not necessary unlimited such as freshwater. Drought and overuse could make it limited.

Nonrenewable resources cannot be replenished by natural processes such as fossil fuels: coal, oil and natural gas. _________________ formed over millions of years from buried organic materials.

____________________________ – is a way of using natural resources at a rate that does not deplete them. This system operates without causing long-term harm to the ecological resources on which it depends.

Land Resources – Soil can be permanently damaged if it is mismanaged. Soil erosion occurs when the surface soil wears away by water or wind. Plowing the land

removes roots that hold the soil in place and can cause soil to erode easily. ________________________ occurs in dry climates, when a combination of farming,

overgrazing and drought has turned once productive areas into deserts. ________________________ occurs when forests are cut down and lead to severe erosion

as soil is exposed to heavy rains. Erosion can wash away nutrients. Grazing and plowing after deforestation can change the soil and microclimates that in turn prevent the re-growth of trees.

There are a variety of sustainable-use practices that can reduce these problems such as contour plowing -- leaving previous year’s crop in place to help hold the soil -- crop rotation and livestock rotation – harvest mature trees.

Water Resources – Overfishing occurs when fish stocks are being harvested faster than they can reproduce.

Depletion of this food resource can alter the ecosystem by collapsing fish populations. ______________________ such as chemicals, waste and sewage enter the water cycle and

contaminate water. Pollutants can increase the growth of algae and bacteria.Sustainable use of resources includes limit fishing and use aquaculture to farm aquatic organisms. Protection of natural water systems such as wetlands to filter pollutants.

Air Resources – _________________ – mixture of chemicals that create a haze in the atmosphere. Primarily

due to automobile exhaust and industrial emissions. ______________________ - Burning of fossil fuels release acidic gases containing nitrogen and

sulfur compounds into the atmosphere. These gases combine with water vapor to form nitric and sulfuric acids.

Acid rain changes the chemistry of the soil. Lowering the soil pH leaches away nutrients and reduces nutrient availability. It also increases availability of toxic elements like mercury from the soil which can enter other parts of the biosphere.Acid rain changes the chemistry of the water killing aquatic organisms. Acid rain causes corrosion of metals.

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Biodiversity – refers to the number of different species in a given area --- variation of life in the biosphere including species, ecosystem and genetic diversity. Species play an important role in an ecosystem because species are either dependent on or depended upon by at least one other species. When on species disappears from an ecosystem, a strand in a food web is removed.

___________________________ are critical to the functioning of an ecosystem. These species control the population size of organisms in lower tropic levels.

Threats to biodiversity include altering habitats, hunting species to extinction, introducing toxic compounds into food webs and introducing invasive species to new environments. About 65 million years ago, a series of changes in the Earth’s climate and ecosystems caused the extinction of about half the species of Earth. It takes many years for biodiversity to rebound after a mass extinction, the extinction of many species in a short period of time. Large populations that adapt easily too many habitats are not likely to become extinct (i.e. rats & cockroaches). Species with small populations in limited areas can easily become extinct. At risk species include those that migrate, those that need special habitats and those that are exploited by humans.

o Endangered species – A species that is likely to become extinct if protective measures are not taken immediately.

o Threatened species – A species that has a declining population and that is likely to become endangered if it is not protected.

1. _____________________________________________ – As human populations grow, we use more land to build homes and harvest resources. Humans destroy and fragment the habitats of other species. Natural habitats are destroyed and the remaining pieces of habitat contain fewer species and less diversity. It is estimated that habitat loss causes almost 75% of the extinction now occurring.

2. __________________________ – A non-indigenous species is introduced into a particular region and can threaten native species that have no natural defenses against them.

3. Excessive Hunting, Harvesting and Poaching – Many countries now have laws to regulate hunting, fishing, harvesting and trade of wildlife.

4. Pollution – Chemicals used by humans are making their way into food webs around the world. The long-term effects may not be clear until after many years of use (i.e. DDT & bald eagle).

_____________________________________ occurs when toxic substances enter the food chain. Concentrations of harmful substances increase in organisms at higher trophic levels in the chain or web.

CRITICAL areas of Biodiversity –Some parts of the world contain a greater diversity of species than others. An important feature is that they have a large portion of endemic species ---- species that are native to and found only within a limited area. Ecologist often use the numbers of endemic species of plants as an indicator of overall biodiversity, because plants from the bases of ecosystems on land.

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o The remaining tropical rain forests cover less than 7% of the Earth’s land. Biologist estimate that over ½ of the world’s species live in these forests. Unknown numbers of species are disappearing as tropical forests are cleared for farming or cattle grazing.

o Coral reefs occupy a small fraction of the marine environment yet contain the majority of the biodiversity. Nearly 60% of Earth’s reefs are threatened by human activities such as overfishing and pollution. Similar threats affect other coastal ecosystems which are travel routes for many migrating species and are linked to ecosystems on land.

o Biodiversity hotspots have high numbers of endemic species and are the most threatened areas on Earth. Most hotspots have lost 70% of their original natural vegetation. The U.S. hotspots include the Florida Everglades, the Californian coastal region, Hawaii, the Midwestern prairies and the forest of Pacific Northwest.

Ozone – The ozone contains a layer of ____________________ (O3) in the upper atmosphere of Earth. It is naturally occurring and ________________ much of the ultraviolet (UV) radiation emitted by the sun from reaching Earth’s surface. Ozone is a “global sunscreen”. The increase in UV radiation causes sunburn, cancer, damage plant leaves, phytoplankton and decrease organisms’ resistance to disease.

Ozone depletion is caused by chlorofluorocarbons (________). CFCs are used in aerosol cans and as coolants in refrigerators and air conditioners. In the cold of the polar atmosphere, CFCs act as catalysts that enable UV light to break apart ozone molecules.

Greenhouse Effect – The Greenhouse Effect is a natural process in which atmospheric gases ___________________________________ (heat). Some of sun’s radiation is reflected back into space, but some passes through and is absorbed by Earth. Heat from the Earth is radiated outward and absorbed by “greenhouse gases”. Greenhouse gases regulate our climate by trapping heat and keeping Earth warm enough to sustain life. The main greenhouse gases are Carbon Dioxide (CO2), Methane (CH4) and Nitrous Oxide (N2O). Humans accelerate this natural process by creating more greenhouse gases in the atmosphere through activities such as:

Burning fossil fuels – deforestation -- creates more CO2

Industrial processes and mining -- emissions from livestock and agricultural practices -- decomposition in landfills – creates more CH4

Agricultural and industrial practices – combustion of fossil fuels and solid waste – creates more N2O

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Ultimately, more greenhouse gases mean more infrared radiation trapped which gradually increases the temperature of the Earth’s surface. This increase in average temperature of the biosphere is called _________________________.

Impacts of Global Warming: Ice sheets and glaciers are melting worldwide, especially at the Earth’s poles. Ecosystems will change—some species will move farther north or become more successful; others won’t be able to move and could become extinct. Sea level rise became faster over the last century. Precipitation has increased across the globe, on average. Floods and droughts will become more common.Less fresh water will be available. Hurricanes and other storms are likely to become stronger. Species that depend on one another may become out of sync. For example, plants could bloom earlier than their pollinating insects become active. Some diseases will spread such as malaria carried by mosquitoes.

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