Table of Contents Letter to the Student...................................... 5 Letter to the Family....................................... 6 Ohio Academic Content Standards Correlation Chart........... 7 Investigation 1.......................................... 11 Ohio Academic Content Standards Chapter 1 Earth Systems................................ 17 Lesson 1 Carbon, Oxygen, and Nitrogen Cycles... 18 ESS.C.1 Lesson 2 Effects of Pollution.................. 22 ESS.C.2 Lesson 3 The Water Cycle.................... 27 ESS.C.3 Lesson 4 Fresh Water........................ 30 ESS.C.4 Lesson 5 Clouds and Predicting Weather........ 34 ESS.C.5 Lesson 6 Making and Reading Weather Maps.... 38 ESS.C.6, ESS.C.7 Lesson 7 Extreme Weather................... 44 ESS.C.9 Lesson 8 Climate Zones and Biomes............ 48 ESS.C.8 Chapter 1 Review........................... 52 Chapter 2 Life Sciences................................. 57 Lesson 9 Body Plans of Organisms............. 58 LS.A.1 Lesson 10 The Diversity of Living Things.......... 63 LS.B.8 Lesson 11 Relationships among Organisms....... 67 LS.C.2 Lesson 12 Changes and the Environment......... 71 LS.C.3, LS.D.4, LS.D.5 Lesson 13 Photosynthesis and Energy Transfer.... 75 LS.C.7 Lesson 14 Factors Affecting the Transfer of Energy in Ecosystems...................... 80 LS.C.6 Chapter 2 Review........................... 84 Chapter 3 Physical Sciences............................. 89 Lesson 15 Conservation of Matter............... 90 PS.A.1 Lesson 16 Forms of Energy.................... 96 PS.D.3 Lesson 17 Transformations of Energy........... 100 PS.D.2, PS.D.4, PS.D.5 Chapter 3 Review.......................... 104 Duplicating any part of this book is prohibited by law. 3
Ohio Achievement Test Coach, Science, Grade 7 Chapter 4 Science and Technology...................... 107 Lesson 18 Technological Development.......... 108 ST.A.1, ST.B.4 Lesson 19 Environmental and Economic Concerns......................... 114 ST.A.2 Lesson 20 Limits of Science and Technology..... 118 ST.A.3 Chapter 4 Review.......................... 122 Chapter 5 Scientific Inquiry............................. 125 Lesson 21 Variables and Controls.............. 126 SI.A.1, SI.A.2 Lesson 22 Formulating Scientific Questions...... 131 SI.A.3 Lesson 23 Tools and Instruments.............. 137 SI.A.4 Lesson 24 Safety........................... 141 SI.A.4 Lesson 25 Organizing, Analyzing, and Interpreting Data................... 145 Chapter 5 Review.......................... 151 SI.B.5, SI.B.6, SI.B.7 Chapter 6 Scientific Ways of Knowing.................... 159 Lesson 26 Eliminating Bias.................... 160 SWK.B.1, SWK.B.2 Lesson 27 Thinking Scientifically............... 165 SWK.C.3 Chapter 6 Review.......................... 168 Investigation 2......................................... 171 Glossary.............................................. 179 4 Duplicating any part of this book is prohibited by law.
9 Body Plans of Organisms LS.A.1 Getting the Idea Key Words multicellular body plan symmetry asymmetrical radial symmetry bilateral symmetry vertebrate invertebrate anterior posterior ventral dorsal segmentation Earth is home to millions of different kinds of living things. Scientists divide them into two large groups: single-celled organisms and multicellular organisms those with more than one cell. All bacteria, most protists, and some fungi are single-celled. Multicellular organisms include all plants and animals, and some protists and fungi. One way scientists study and group these organisms is by looking at their body plans. Body Plans An organism s body plan is the way its structures are arranged. Some animals do not have a definite body shape or true tissues. Others have regular body shapes that are well organized into tissues, organs, and organ systems. Scientists often describe the body plans of animals in terms of symmetry. Symmetry is balance among the parts of something. If you drew a line down the middle of your body, your two halves would be very similar. Each half would have one eye, one ear, half a nose, one arm, one leg, and so on. Symmetry is a clue to how an animal s cells are arranged. Asymmetry The simplest animals are asymmetrical without symmetry. An asymmetrical animal does not have a regular body shape. Sponges are asymmetrical. Like all animals, sponges are multicellular. Many of the cells in sponges carry out specific jobs, but these cells are not arranged into tissues. Some examples of sponges are shown on the next page. 58 Duplicating any part of this book is prohibited by law.
Ohio Achievement Test Coach, Science, Grade 7 Bilateral Symmetry More complex animals have bilateral symmetry, or two similar halves. Their body parts tend to be arranged in pairs along a central axis. One side of the animal is almost a mirror image of the other. All vertebrates have bilateral symmetry. A vertebrate is an animal that has a backbone. Many invertebrates, such as insects and worms, also have bilateral symmetry. An invertebrate is an animal that does not have a backbone. Bilateral Symmetry Animals with bilateral symmetry have right and left sides. They have a head or anterior end, and a tail or posterior end. They also have a ventral or belly side and a dorsal or back side. Anterior Dorsal Anterior Dorsal Ventral Posterior Ventral Posterior Most animals with bilateral symmetry have well-developed nervous systems and sense organs. The sense organs, such as eyes and ears, are most often located at the anterior or head end of the animal. Many animals with bilateral symmetry have structures that aid in movement, such as limbs, wings, or fins. These structures enable many of them to move much more quickly and easily than most animals with radial symmetry. 60 Duplicating any part of this book is prohibited by law.
Lesson 9: Body Plans of Organisms Segmentation The body plan of some animals includes segmentation. These animals have bodies that are divided into repeating units or segments. In animals such as earthworms, you can see the segmentation from the outside of the animal. Mouth Brain Earthworm Digestive tract Blood vessels Nerve cord Reproductive organs Anus Waste-removal organs Intestine Caterpillar Some animals show segmentation during only part of their life cycle. The caterpillar stages of butterflies and moths are examples. Other animals have segmented structures inside their bodies. For example, the backbones of vertebrates are made up of small bones called vertebrae. Each of these bones is one segment of the backbone. The segments are connected in a way that supports the animal and allows it to move. DISCUSSION QUESTION Symmetry is not limited to animals. What everyday objects or other organisms can you identify that show each type of symmetry? LESSON REVIEW 1. Which of these groups of animals is asymmetrical? A. sea stars C. earthworms B. lions D. sponges Duplicating any part of this book is prohibited by law. 61
Ohio Achievement Test Coach, Science, Grade 7 2. The illustration shows a camel that has two humps. Which term describes the side of the camel on which the humps are located? A. anterior B. posterior C. dorsal D. ventral 3. Which of these organisms has radial symmetry? A. jellyfish B. sponge C. wolf D. whale 4. Where are the sense organs of an animal with bilateral symmetry most likely to be located? A. on its dorsal side B. at its anterior end C. at its posterior end D. on its ventral side 62 Duplicating any part of this book is prohibited by law.