California science vocabulary card(1 6) (4) California science grade 5 (6)
Chapter Chapter About 8,000 waves strike the Big Sur coastline every day CHAPTER Earth’s Ecosystems How organisms exchange energy and nutrients in an ecosystem? 20 Lesson Introduction to Earth’s Ecosystems PAGE 24 Lesson Photosynthesis: The Basic Process of Life PAGE 40 Lesson Microscopic Organisms on Earth PAGE 54 Lesson Earth’s Food Chains, Webs, and Pyramids PAGE 66 Lesson Earth’s Cycles for Life PAGE 80 LS Organisms in ecosystems exchange energy and nutrients among themselves and with the environment 21 Literature POEM ELA R 6.3.6 Identify and analyze features of themes conveyed through characters, actions, and images • ELA W 6.2.4 Write responses to literature 22 from MY AMERICA ed Lee Bennet Hopkins by Natasha Wing Redwood trees rise like skyscrapers Fingering the clouds in search of moisture Pulling down the fog and passing it From limb to limb Into the deep of the forest The fog blankets the forest Blocking out light, movement, and sound Like a curtain Draped across a stage Yet behind the redwood curtain Black bear walk and stalk their prey Deer sleep and leap away Slugs climb and slime on leaves Birds sing and wing in the breeze The show must go on As it has for thousands of years Behind the redwood curtain Write About It Response to Literature In this poem the author describes a forest What is life like in this forest? What plants and animals live there? Write an essay explaining the main idea of the poem Use details from the poem to show how the author makes her point -Journal Write about it online @ www.macmillanmh.com 23 Lesson Introduction to Earth’s Ecosystems California is home to one of the most diverse collections of living things in the world Why you think this is so? 24 ENGAGE LS 5.e Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition Materials Do different ecosystems contain different organisms? Form a Hypothesis Why certain plants and animals live in certain places? How does the amount of sunlight affect different organisms? Write your answer as a hypothesis in the form “If a plant needs lots of sunlight, then ” • trowel or spade • small stakes Test Your Hypothesis Experiment With your teacher select two • meterstick areas on or near your school grounds to study Choose one area that receives plenty of sunlight and another that receives very little Mark off a 2-by-2-meter plot in each area with stakes and string • string Measure Measure the air temperature at • safety goggles ground level and at meter above ground level in each area • thermometer • field guides • graph paper Step Record Data Using graph paper record the locations of the living things in each area What kinds of organisms you see? Use field guides to help you identify the organisms Draw Conclusions Compare your observations about the two areas How the temperatures differ? Which area contains more living things? What statement can you make about the effect of sunlight on an ecosystem? Explore More Step How you think the amount of water in an ecosystem affects living things? Make a prediction about this, and design a procedure to test it How have people affected the ecosystem? IE 7.a Develop a hypothesis • IE 7.e Recognize whether evidence is consistent with a proposed explanation 25 EXPLORE What Is an Ecosystem? ▶ Main Idea LS 5.e The number and types of organisms in an ecosystem depend on the resources available ▶ Vocabulary ecosystem, p 26 biotic factor, p 27 abiotic factor, p 27 humus, p 32 topsoil, p 32 minerals, p 32 acidity, p 33 alkalinity, p 33 ecology, p 34 population, p 34 community, p 35 habitat, p 36 niche, p 36 www.macmillanmh.com ▶ Reading Skill Main Idea ;OW\7RSO 2SbOWZa Explore ecosystems with a park ranger 26 EXPLAIN The living things in an area also work together in systems They all depend on the same resources and are affected by changes that occur around them For example, a major change in a nonliving part of an ecosystem, such as an extreme drought, can affect all the organisms in an ecosystem Living things are part of an ecosystem An ecosystem consists of the living and nonliving things in an area that interact with one another An Ecosystem -Glossary @ A system is a group of things that work together as a unified whole There are systems all around you Our bodies contain organ systems for breathing and for digesting food Schools are organized into school systems Planets are part of our solar system Each system is made up of parts that interact with one another closely Ecosystems Any living thing that is part of an ecosystem is a biotic factor This term includes the root bio, which means “living.” Living things include tiny organisms, such as bacteria, as well as the plants and animals people can see Any nonliving part of the ecosystem, such as water, minerals, sunlight, air, or soil, is an abiotic factor This term includes the prefix a-, which means “not” or “without.” How can you identify the abiotic factors in an ecosystem? Abiotic factors are the parts of the ecosystem that help make life possible For example, sunlight provides warmth and energy Rocks provide shelter and, in time, form soil Water is so important to living things that it is what scientists look for first when searching for signs of life on other planets Other abiotic factors include air, climate, and altitude All these factors influence the number and types of organisms that can live in an ecosystem Identifying the living things in an ecosystem might seem to be easy At the beach you might see birds, fish, seals, and seaweed In contrast, think about microscopic organisms inside your mouth The warm, moist environment there supports millions of bacteria Quick Check Main Idea What are five abiotic factors in an ecosystem? Critical Thinking How biotic and abiotic factors differ? Reading Diagrams How would the abiotic factors shown here affect the organisms that live in the pond? Clue: What are the nonliving things in the picture? 27 EXPLAIN Why are sunlight and temperature important? The amount of sunlight a location receives directly affects the temperature in that location Temperature, in turn, affects the number and types of animals and plants that can survive in a location Sunlight Areas of Earth that receive greater amounts of sunlight have higher temperatures than other areas The equator is the part of Earth that receives the most direct sunlight Areas around the equator that are not at extremely high elevations are generally known for their lush vegetation and great diversity of living things The parts of Earth that receive the least direct sunlight are the North and South poles Areas near the poles have sparse or no vegetation and fewer kinds of living things For most organisms, especially plants, sunlight is an important abiotic factor Temperature Temperature change is another factor that affects living things In some regions the temperature changes very little ◀ Parrots thrive in warm climates, such as the Amazon rain forest 28 EXPLAIN Materials How does water recycle itself? Make a Prediction All living things rely on water, yet there is a limited supply of water on Earth Water is recycled so that it can be used again and again What will happen to soil if it is moistened with water and then placed under a heat source? Write your answer as a prediction in the form “If moistened soil is allowed to sit under a heat source, then the water in the soil will ” • empty soda bottle with cap (cut into halves) Test Your Prediction Place about inches of soil in the bottom half of the soda bottle • soil Spray the soil with water so that it is moist but not wet • lamp or window with sunlight Secure the top half of the soda bottle over the bottom half Use tape if necessary • water spray bottle Step Observe Place the bottle under a lamp or in direct sunlight Observe it every 10 minutes for a class period Write down your observations Observe the bottle again on the second day Write down your observations Draw Conclusions What did you see the first day? What did you see the second day? Infer What was the source of the water? What Step was the source of the energy that caused changes in the bottle? Observe What happened to the water? Explore More What might happen if you added some small plants to the bottle? Some small rocks? What might happen if you added more heat or placed the bottle in the shade? IE 7.e Recognize whether evidence is consistent with a proposed explanation 81 EXPLORE ▶ Main Idea LS 5.b Earth recycles water and other substances, such as carbon and nitrogen ▶ Vocabulary precipitation water cycle, p 83 evaporation, p 83 condensation, p 83 precipitation, p 83 carbon cycle, p 84 nitrogen cycle, p 86 nitrate, p 87 nitrite, p 87 composting, p 88 -Glossary @ www.macmillanmh.com How does Earth have enough air and water to keep us alive? You know that people recycle bottles, cans, and newspapers to help the environment Did you know that the environment recycles itself, too? The air people breathe and the water people drink not run out, because the planet is always recycling them ▶ Reading Skill Main Idea ;OW\7RSO The Water Cycle 2SbOWZa Ac\ ^`SQW^WbObW]\ Q]\RS\aObW]\ Q]ZZSQbW]\ `c\]TT SdO^]`ObW]\ 82 EXPLAIN Golden Gate Bridge, San Francisco, California condensation The Water Cycle A cycle is a series of events that happen one after another, in the same order, over and over again Think about a bicycle Why you think it is called that? It has two wheels (bi-) that go around and around (-cycle) The water cycle is the continuous movement of water between Earth’s surface and the air The water cycle works because water can change from a solid to a liquid to a gas and back again The energy from the Sun powers the water cycle The Sun heats the water in oceans, lakes, rivers, ponds, and puddles This causes evaporation , the process in which a liquid changes into a gas As the water vapor moves higher into the atmosphere, it cools and condenses into tiny water droplets Condensation is the process in which a gas changes into a liquid Condensation causes water to form on the outside of a cold glass of lemonade on a hot day Droplets of condensed water accumulate in clouds When the droplets become too heavy, they fall to Earth’s surface Precipitation is any form of water—rain, snow, sleet, or hail—that falls to Earth When water hits Earth’s surface, it may soak into the ground and be stored as groundwater, in a process called collection It may also run across the surface and be collected in streams, ponds, lakes, oceans, or other bodies of water Some of this collected water evaporates back into the atmosphere About 85% of the water that evaporates on Earth comes from the ocean Most of this water quickly condenses and falls back into the ocean Water evaporates from both freshwater and saltwater sources However, all of the precipitation that falls on Earth is fresh water The salt is left behind when salt water evaporates Quick Check Main Idea What form of water does condensation produce, a liquid, a solid, or a gas? Critical Thinking What is the order of the four parts of the water cycle? 83 EXPLAIN What is the carbon cycle? Carbon is one of the elements that make up all living things Plants and animals (including people) need carbon to live There is not a lot of carbon in the atmosphere, so it must be recycled Otherwise it would be used up too quickly The process in which carbon is recycled between the atmosphere and living things is called the carbon cycle There is evidence that a buildup of gases such as carbon dioxide, nitric oxide, and methane trap heat that normally would escape from Earth’s atmosphere Called the greenhouse effect, this buildup raises temperatures and leads to global warming Since 1850 the average temperature on Earth has risen about 1.8°F (1°C ) Some scientists predict it will rise 3.5°F (2°C) by the year 2100 They believe this rise will lead to many problems, such as the melting of the polar ice caps, which would cause sea levels to rise and flood coastal areas The Carbon Cycle Carbon enters the air in three ways: when plants and animals decay; when animals breathe out (exhale); and when fossil fuels such as coal, oil, gasoline, and natural gas are burned Plants During photosynthesis, plants use the carbon from carbon dioxide to make sugars, starches, and proteins They also give off oxygen, which is used by animals Death and decay When living things die, the carbon in them goes into the air and the ground Some of it is turned into carbon dioxide by the organisms that feed on dead organisms 84 EXPLAIN Carbon and Life Carbon is stored in molecules of living and dead organisms, in organic matter in soil, in the air as carbon dioxide, and in fossil fuels Dissolved carbon dioxide is also found in the ocean and in the shells of some marine organisms Plants and other photosynthetic organisms take in carbon dioxide and water and use them to make food During this process, oxygen is released into the atmosphere as a waste product When living things need to use the energy that has been stored in food, they use oxygen to break apart the molecules during respiration The final products are energy, water, and carbon dioxide The carbon dioxide is returned to the atmosphere, continuing the cycle Quick Check Main Idea Why is the carbon cycle important to living things? Critical Thinking Where does the carbon that has been stored in an animal’s body go when the animal dies? Reading Diagrams What happens to carbon when living things die? Clue: Read the text boxes Storage Some carbon is stored as fossil fuels This is the carbon left behind by certain organisms that died millions of years ago Animals Animals eat plant sugars, starches, proteins, and other substances The animals use the carbon in these foods to make their own body chemicals 85 EXPLAIN The Nitrogen Cycle nitrogen gas nitrites with ammonia nitrites nitrates What is the nitrogen cycle? All living things must have nitrogen to develop and grow Nitrogen is needed to make proteins, which are the building materials for muscles, skin, bones, blood, plants’ cell walls, and internal organs Just like water and carbon, nitrogen is cycled through the environment The nitrogen cycle is the continuous trapping of nitrogen gas into compounds in the soil and the returning of nitrogen gas to the air Earth’s atmosphere is 78% nitrogen You would think this would be enough to supply living things with the nitrogen they need However, plants and animals cannot use nitrogen in this form Plants must get nitrogen 86 EXPLAIN from nitrogen compounds in the soil that have been made usable Animals then get nitrogen in the same way they get energy—by eating plants or by eating the animals that eat the plants that absorb the nitrogen Uses of Nitrogen Lightning can change the nitrogen found in the atmosphere into a watersoluble compound that dissolves in rainwater to form nitric acid A small amount of nitrogen is absorbed into soil this way The rest of the nitrogen in soil comes from bacteria Certain bacteria, called nitrogen-fixing bacteria, live in Fertilizers Fill two plastic cups with pond water or water from an aquarium Add a few water plants, such as elodea, to each cup Add a teaspoon of houseplant food to one cup, and label the cup Be Careful Always wear protective gloves when handling plant foods nitrogen compounds Reading Diagrams What role decomposers play in the nitrogen cycle? Observe Place both cups in a sunny window, and observe them each day for a week Record your observations Interpret Data What effect did the plant food have on the plant growth in the cups? What is the independent variable in this lab? What is the dependent variable? Clue: Where plants obtain nitrogen from? the roots of beans, peas, and peanuts and can extract nitrogen from the air Other bacteria convert this nitrogen into usable compounds called nitrates and nitrites Plants absorb the nitrates and nitrites and use them to make proteins These proteins are passed along when animals eat plants and one another When plants and animals die, nitrogen from their remains returns to the soil when bacteria break it down into nitrogen gas These bacteria return about the same amount of nitrogen to the air as other bacteria take from the air, keeping nature in balance Quick Check Main Idea What is the nitrogen cycle? Critical Thinking Why some people use manure, or raw animal wastes, in their gardens? 87 EXPLAIN How are plants recycled? Plants are necessary to each of nature’s cycles Plants continue their work even after they die Think of a giant tree falling in a forest Right away it becomes a habitat for many different animals, including birds, frogs, and insects Soon after it falls, the tree begins to break down Decomposers are organisms that break down dead plants and animals into useful things such as minerals and rich soils Plants need these in order to grow As you can see, each kind of organism has a role that helps others survive Worms, crickets, cockroaches, bacteria, and fungi are decomposers These organisms help plants survive ▼ The yellow coral fungus helps break down this fallen tree composting Composting What happened to the fallen tree also applies to your yard and some of the food scraps around your home Certain kinds of scraps from the food you eat or cuttings from your yard still contain nutrients and other substances that can be recycled Composting is the process in which decomposers break down organic matter so it can be used as a natural fertilizer for gardening or farming You can make compost by mixing three parts dry leaves and plant material, one part fresh grass clippings, and one part vegetable food scraps Decomposers soon go to work, breaking down these materials into nitrogen and other elements that make the soil rich Quick Check Main Idea What is the role of decomposers in an ecosystem? Critical Thinking What is the first thing that happens when a tree dies and falls down? 88 EXPLAIN Summarize the Main Idea The water cycle is the continuous movement of water between Earth’s surface and the atmosphere (pp 82–83) The carbon cycle is the process in which carbon moves between the atmosphere and living things (pp 84–85) The nitrogen cycle is the movement of nitrogen among air, soil, plants, and animals (pp 86–87) Make a Study Guide Make a three-tab folded book (see pp 487–490) Use the titles shown On the inside of each tab, write two sentences about the main idea of the topic Writing Link Think, Talk, and Write Main Idea Earth water, carbon, and nitrogen Vocabulary The process in which a gas changes into a liquid is Main Idea What happens to the nitrogen compounds that are not absorbed by plants? ;OW\7RSO 2SbOWZa Critical Thinking What would happen if Earth became much warmer? Test Practice Which of the following objects would most likely take the longest to decompose? A plastic bottle B eggshell C paper bag D schoolbook Test Practice What is the process in A B C D which a liquid changes into a gas? precipitation evaporation condensation collection Math Link Expository Writing Estimate Fresh Water Research a local environmental problem that is related to water or air How does this problem result from human activities? Of Earth’s fresh water, 69% is polar ice, 30% is groundwater, and 0.9% is permafrost What percent of Earth’s fresh water is available for use by people? -Review Summaries and quizzes online @ www.macmillanmh.com 89 EVALUATE Materials Inquiry Structured What factors affect the carbon, water, and nitrogen cycles? Form a Hypothesis small cup bromothymol blue The carbon cycle is a series of events that recycles carbon through the environment Carbon exists in many forms and can be found in the air and in plants and animals Plants take in carbon dioxide from the air and convert it into food and oxygen The amount of carbon found in the air is affected by air pollution, especially pollution from the burning of fossil fuels What role plants play in the carbon cycle? Write your answer as a hypothesis in the form “If carbon dioxide is added to a system containing a plant, then ” Be Careful Wash your hands with soap and water after the investigation Immediately wash any area of skin that comes in contact with bromothymol blue elodea Test Your Hypothesis Step Use a straw to blow slowly into a small cup of bromothymol blue Record your observations in your journal test tube with cap straw Be Careful Be sure to breathe out through the straw Do not breathe in Do not drink the liquid in the cup Measure Pour 10 milliliters of bromothymol blue into a test tube Record the color of the liquid in your journal Experiment Use a straw to blow gently into the test tube until the liquid turns light green Place one piece of elodea in the test tube, and put the cap on the tube graduated cylinder 90 EXTEND Place the test tube in a rack near a window, and check the color of the bromothymol blue every 30 minutes for hours Record the color of the liquid at each interval IE 7.a Develop a hypothesis Step Step Draw Conclusions Explain What made the bromothymol blue change color in step 1? Analyze If you had continued blowing into the test tube instead of capping it, what you think would have happened during the 2-hour experiment? Infer What part of the carbon cycle did you represent when you blew into the test tube? Inquiry Guided What factors affect the water cycle? Form a Hypothesis Does temperature affect the water cycle? Write your answer as a hypothesis in the form “If the average air temperature changes over a long period of time, then the water cycle will ” Test Your Hypothesis Design an experiment to investigate how temperature affects the water cycle Write out the materials you need and the steps you will follow Record your results and observations Draw Conclusions Did your results support your hypothesis? Why or why not? What you think would happen to the water cycle in a large land area if volcanic ash blocked the Sun’s rays for a few months? Inquiry Open What can you learn about the nitrogen cycle? For example, does pollution affect it? Come up with a question to investigate Then design an experiment to answer your question, and carry out your experiment Organize your experiment to test only one variable, or one item being changed Write down the steps so that another group could complete the experiment by following your instructions Remember to follow the steps of the scientific process Ask a Question Form a Hypothesis Test Your Hypothesis Draw Conclusions 91 EXTEND CHAPTER Review Summarize the Main Ideas An ecosystem consists of the living and nonliving things in an area that interact with each other (pp 24–37) Fill each blank with the best term from the list abiotic factor, p 27 nitrogen cycle, p 86 energy pyramid, p 76 omnivore, p 73 eukaryote, p 58 Photosynthesis is the process of making food by using sunlight (pp 40–51) Microscopic producers, consumers, and decomposers are parts of the food chain (pp 54–63) Food chains, webs, and pyramids show how energy flows within an ecosystem (pp 66–77) Water, carbon, and nitrogen cycle through the living and nonliving parts of the environment (pp 80–89) Make a Study Guide transpiration, p 48 water cycle, p 83 niche, p 36 Energy from sunlight is a(n) LS 5.e Everything an organism does and everything it needs make up its LS 5.e A complex organism that has a nucleus in each cell would be classified as a(n) LS 5.b A(n) would eat both producers and consumers LS 5.b, c The term describes the loss of water from leaves LS 5.a A model showing how energy moves through a food chain is a(n) LS 5.b Evaporation, condensation, and precipitation are parts of the LS 5.b Denitrifying bacteria are an important part of the LS 5.b Take a sheet of paper and tape your lesson study guides as shown Use the study guides to answer the questions on these pages 92 -Review Summaries and quizzes online @ www.macmillanmh.com Answer each of the following in complete sentences Cause and Effect What effect would over-logging of trees have on the amount of carbon dioxide in the atmosphere? LS 5.a Save the Trees Suppose a kind of insect is destroying all the Joshua trees Your goal is to convince state officials that funding must be made available to save the Joshua trees What to Do 10 Critical Thinking How does the angle at which the Sun’s rays strike Earth affect the number and types of organisms found in different areas of the world? LS 5.b, e 11 Predict What two effects might occur if most of the phytoplankton living in the world’s oceans were destroyed? LS 5.a 12 Infer Explain why Earth is probably the only planet in our solar system that has soil LS 5.b 13 Explanatory Writing Be a teacher for the day How would you explain the nitrogen cycle to your students? LS 5.b Find out what niche the Joshua trees occupy In what ways other organisms living in the same ecosystem depend on these trees? Prepare a display to show officials how the destruction of the Joshua trees could disrupt the food chains in the ecosystem Analyze Your Results ▶ Explain how a disruption in one part of an ecosystem can have far-reaching effects ▶ Would the benefits of saving the Joshua tree outweigh the risks of spraying to prevent insect damage? How organisms exchange energy and nutrients in an ecosystem? 16/>B3@ 93 What microscopic organisms provide to larger organisms? LS 5.b A B C D fresh water composing organisms increased sunlight food A B C D Which of the following types of organisms turns energy from the Sun into chemical energy? LS 5.a A B C D to to to to eat the bacteria in the soil store carbon for the plants break down plant proteins turn nitrates into nitrogen gas 5 Why are organisms such as earthworms and fungi called decomposers? LS 5.c producers consumers decomposers composers A They break down very quickly after they die B They break down other organisms into simpler substances C They are the only organisms that cannot make their own food D They break down carbon dioxide into oxygen through respiration Look at the table below Category A Category B tomato plant elephant fern panther cyanobacteria humpback whale willow tree field mouse grass hawk These organisms are grouped into LS 5.c A decomposers and tertiary consumers B primary consumers and scavengers C producers and consumers D omnivores and producers 94 4 What is the role of a decomposer when plants die? LS 5.b Which of the following best describes the role of roots and stems in a plant? LS 5.a A Roots and stems transport water and minerals to the leaves so that photosynthesis can occur B Roots and stems help the plant move and keep cool in hot weather C Roots and stems transport water and minerals to the flowers to attract bees so that pollination can occur D Roots and stems are where photosynthesis takes place The diagram below shows an ocean energy pyramid 10 The energy in a community flows from producer to primary consumer and from primary consumer to LS 5.c A B C D tertiary consumer decomposer secondary consumer top predator 11 A scientist observes a crow eating both insects and grass What can she conclude about crows? IE 7.e A Crows will never eat higher-level consumers B The crow will always eat only Which organism in the energy pyramid is a secondary consumer? LS 5.b A B C D seal penguin fish plant 8 What adaptations plants have to live in desert environments? LS 5.e A They reflect light from the Sun B They migrate during the day to cooler areas C They store water in spongy tissues D They not grow in desert environments 9 Microscopic organisms that recycle organic materials back into the food chain are LS 5.b A B C D insects or grasses C The crow is the only organism that eats insects and grasses D Crows will eat both insects and grasses 12 Some populations occupy niches of such importance that many other organisms depend on them These populations are called keystone species Which of the following is an example of a keystone species? LS 5.e A Venus’s-flytraps catching flies in the garden B moles digging in the soil, creating long tunnels under grass C beavers building a dam, creating a valuable wetland D birds building a nest high up in a tree producers decomposers users consumers Materials prepared by PASS at 95 ... off California are another population At one time, people hunted elephant seals for their oil until only about 100 remained Today, there are many elephant seals along California s coast California. .. 7.e Recognize whether evidence is consistent with a proposed explanation 25 EXPLORE What Is an Ecosystem? ▶ Main Idea LS 5. e The number and types of organisms in an ecosystem depend on the resources... Introduction to Earth’s Ecosystems California is home to one of the most diverse collections of living things in the world Why you think this is so? 24 ENGAGE LS 5. e Students know the number and