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Common Core Standards: ELA - Literacy See All Teacher Resources

Grade 9-10

Reading RST.9-10.2

RST.9-10.2. Determine the central ideas or conclusions of a text; trace the text’s explanation or depiction of a complex process, phenomenon, or concept; provide an accurate summary of the text.

Set the Stage

As in other content areas, clarifying main ideas in the scientific or technical text is crucial for students. Without this ability, they will often lack the background information to understand simple concepts and to analyze more difficult processes. Develop students’ reading strategies by helping them note headings, key terms, and main ideas. Model how to make connections from one part of the text to another, how to take useful notes from the text (no, there is not always three and only three details for every main idea), and how to use the pictures and diagrams provided to support the reading. You can check students’ understanding of the text or concept by asking them to give a detailed summary. If students can summarize accurately and in their own words, it means they have a pretty good grasp on the material. If not, it’s time to break out some of those rereading strategies. Here’s how to keep your students from becoming mired in the details.


Dress Rehearsal

In biology class, your teacher has asked you to read the section about aquatic ecosystems in your textbook. Excellent! Maybe this will uncover what Swamp People are actually doing. You’re asked to determine the central ideas of the section and then summarize what you’ve read. Aquatic ecosystems are systems grouped according to factors, such as “water flow, depth, distance from shore, salinity, and latitude.”

You’re expected to use one of the reading comprehension strategies you learned in English or reading class in order to understand this concept. Then, you are asked to provide a written summary of what you have read. You may provide this summary through the use of bulleted notes, a graphic organizer, or detailed paragraphs. A real quagmire of an assignment, you think.

You’ve been taught that publishers often use bold and colored text to highlight main points and important details. These act as little maps to get you where you want to go. The main point being to understand what you’re reading. Thanks to the headings and colors used by the textbook, you immediately see that aquatic ecosystems include three types of systems: freshwater, transitional, and marine. These are obvious because they are written in bold, blue letters.

Within each of three aquatic ecosystems are various bodies of water and areas of land that make up that particular type. These are marked in bold, red letters. Finally, specific words that are on the vocabulary list are written in bold, black letters. These words are usually defined and described in a sentence or two, immediately after the word. Eureka! They couldn’t have made it any easier.

As you read like a swamper, you take notes by means of a graphic organizer, using the colors and boldface type as your guide. Your graphic organizer, which provides an exact rundown of the section, might look like this:

Type of EcosystemDistinguishing FeaturesKey Terms & Definitions
Freshwater Rivers and streams
  • Water flows in one direction.
  • Has a headwater (source) and a mouth (empties into a larger body of water).

    Lakes and ponds:
  • An inland body of standing water.
  • Sediment - material deposited by water, wind, or glaciers.

    Littoral zone - area closest to the shore.

    Limnetic zone - open water area, well-lit, filled with plankton.

    Plankton - free floating photosynthetic autotrophs that live in freshwater.

    Profundal zone- the deepest areas of a large lake, colder and lower in oxygen.
    Transitional Aquatic Wetlands:
  • Areas of land, such as a swamp, saturated with water.
  • Where freshwater from a stream or river meets the salt water from the ocean.
  • MarineIntertidal Zone
  • Narrow band where the ocean meets the land.

    Open ocean ecosystems
  • Deep, open water.

    Coastal ocean and coral reefs
  • Natural barriers
  • Corals
  • Symbiotic relationship with algae
  • Sensitive to changes in the environment
  • Photic zone - 200 m of water where sun gets through, has seaweeds and plankton.

    Aphotic zone - area when sunlight cannot penetrate, generally dark and cold.

    Benthis zone - area along the ocean floor made of sand, silt, and dead organisms.

    Abyssal zone - very cold with invertebrates, such as clams and crabs.

    Through the use of a graphic organizer, you have summarized and organized important information in visual form, using bullets to highlight the most important details. The creation of this chart has allowed you to deconstruct a major concept, aquatic ecosystems. You’ve also traced the text’s explanation of what they are. And, you’ve provided an accurate summary of the information, without getting bogged down.


    Biggs, Alton, et al. Biology. McGraw Hill: New York, 2009.

    That’s a Wrap

    Any type of summary is a good formative assessment of this standard, whether it’s a paragraph or two as a ticket out the door, an essay of explanation, or a graphic organizer in visual form. Using the tools publishers provide in these types of texts are excellent mapping strategies for students as they follow explanations and depictions of major concepts. Model how to use these text features as reading strategies, and it will be smooth sailing for you and your students.


    Using the following passage about water pollution, determine main ideas and supporting details. Then create an outline that summarizes the information.

    Industrial Pollution 

    In the United States, industry is the greatest source of pollution, accounting for more than half the volume of all water pollution and for the most deadly pollutants. Some 370,000 manufacturing facilities use huge quantities of freshwater to carry away wastes of many kinds. The waste-bearing water, or effluent, is discharged into streams, lakes, or oceans, which in turn disperse the polluting substances. In its National Water Quality Inventory, reported to Congress in 1996, the U.S. Environmental Protection Agency concluded that approximately 40% of the nation's surveyed lakes, rivers, and estuaries were too polluted for such basic uses as drinking supply, fishing, and swimming. The pollutants include grit, asbestos, phosphates and nitrates, mercury, lead, caustic soda and other sodium compounds, sulfur and sulfuric acid, oils, and petrochemicals.

    In addition, numerous manufacturing plants pour off undiluted corrosives, poisons, and other noxious byproducts. The construction industry discharges slurries of gypsum, cement, abrasives, metals, and poisonous solvents. Another pervasive group of contaminants entering food chains is the polychlorinated biphenyl (PCB) compounds, components of lubricants, plastic wrappers, and adhesives. In yet another instance of pollution, hot water discharged by factories and power plants causes so-called thermal pollution by increasing water temperatures. Such increases change the level of oxygen dissolved in a body of water, thereby disrupting the water's ecological balance, killing off some plant and animal species while encouraging the overgrowth of others.

    Other Sources of Water Pollution 

    Towns and municipalities are also major sources of water pollution. In many public water systems, pollution exceeds safe levels. One reason for this is that much groundwater has been contaminated by wastes pumped underground for disposal or by seepage from surface water. When contamination reaches underground water tables, it is difficult to correct and spreads over wide areas. In addition, many U.S. communities discharge untreated or only partially treated sewage into the waterways, threatening the health of their own and neighboring populations.

    Along with domestic wastes, sewage carries industrial contaminants and a growing tonnage of paper and plastic refuse. Although thorough sewage treatment would destroy most disease-causing bacteria, the problem of the spread of viruses and viral illness remains. Additionally, most sewage treatment does not remove phosphorus compounds, contributed principally by detergents, which cause eutrophication of lakes and ponds. Excreted drugs and household chemicals also are not removed by present municipal treatment facilities, and can be recycled into the drinking water supply.

    Rain drainage is another major polluting agent because it carries such substances as highway debris (including oil and chemicals from automobile exhausts), sediments from highway and building construction, and acids and radioactive wastes from mining operations into freshwater systems as well as into the ocean. Also transported by rain runoff and by irrigation return-flow are animal wastes from farms and feedlots, a widespread source of pollutants impairing rivers and streams, groundwater, and even some coastal waters. Antibiotics, hormones, and other chemicals used to raise livestock are components of such animal wastes. Pesticide and fertilizer residues from farms also contribute to water pollution via rain drainage.

    Ocean Pollution 

    Large and small craft significantly pollute both inland and coastal waters by dumping their untreated sewage. Oil spilled accidentally or flushed from tankers and offshore rigs (900,000 metric tons annually) sullies beaches and smothers birds, fish, and plant life. In 1989 in one of the world's worst single instances of water pollution, the Exxon Valdez spilled 11 million gallons of oil in Prince William Sound, Alaska, causing great environmental destruction. In 1997, the 22 oil spills reported worldwide involved a total of 15 million gallons (57 million liters) of oil. In addition to its direct damage to wildlife, oil takes up fat-soluble poisons like DDT, allowing them to be concentrated in organisms that ingest the oil-contaminated water; thus such poisons enter the food chains leading to sea mammals and people (see ecology).

    Both DDT, which has been banned in the United States since 1972, and PCBs are manufactured in many parts of the world and are now widespread in the Atlantic and Pacific oceans. In addition, tarry oil residues are encountered throughout the Atlantic, as are styrofoam and other plastic rubbish. Plastic bits litter sections of the Pacific as far north as Amchitka Island near Alaska. Garbage, solid industrial wastes, and sludge formed in sewage treatment, all commonly dumped into oceans, are other marine pollutants found worldwide, especially along coastal areas.

    Excerpt from “Water Pollution.” The Columbian Encyclopedia, Sixth Edition. Columbia University Press: 2004. Gale Cengage Learning. 25 April 2012. http://www.questia.com/library/water-pollution.jsp. Web.


    “Water Pollution”
    I. Industrial Pollution
    A. US industry is a major source of water pollution.
    1. Accounts for more than half of the volume of polluted waters.
    2. Accounts for the most deadly pollutants.
    B. 40% of water unusable for drinking, fishing, swimming.
    C. Major pollutants
    1. Pollutants - grit, asbestos, phosphates and nitrates, mercury, lead, caustic soda and other sodium compounds, sulfur and sulfuric acid, oils, and petrochemicals.
    2. Manufacturing pour off, including corrosives, poisons, and other noxious byproducts.
    3. Construction industry - discharges slurries of gypsum, cement, abrasives, metals, and poisonous solvents.
    4. Hot water - factories and power plants cause so-called thermal pollution.

    II. Other Sources of Pollution
    A. Towns and municipalities contribute domestic waste.
    1. Contaminated groundwater from waste disposal and seepage.
    2. Spreading of contaminated water.
    3. Untreated or partially treated waste entering waterways.
    B. Sewage carries industrial contaminants.
    1. Sewage treatment destroys bacteria but not viruses.
    2. Phosphorous compounds from detergents cause eutrophication of lakes and ponds.
    3. Drugs and household products not removed during treatment.
    C. Rain drainage is another major polluting agent.
    1. Carries such substances as highway debris, sediments from highway and building construction, and acids and radioactive wastes from mining operations.
    2. Carries animal wastes from farms and feedlots.
    3. Carries antibiotics, hormones, and other chemicals used to raise livestock in animal waste.
    4. Carries pesticide and fertilizer residues from farms.

    III. Ocean pollution is also a problem.
    A. Large and small aircraft dump sewage into waterways.
    B. Accidental oil spills ruin beaches and kill birds, fish, and flora.
    C. Poisons, such as DDT, enter the food chain.
    D. Styrofoam and plastics find their way to the waterways.
    E. Other miscellaneous pollutants are garbage, solid industrial wastes, and sludge formed in sewage treatment.

    Aligned Resources