LIFE SCIENCE SURVEY TEST

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1 LIFE SCIENCE SURVEY TEST For some questions, there may be more than one correct answer. However, each question has only one best answer. Choose the single best answer from the five choices for each question. 1. Which statement below best describes the relationship between an organism and its cells? a. An organism is a container that has cells inside of it. b. An organism is a container that has cells covering it. c. An organism is one big cell with other cells inside of it. d. An organism is made up of one or more cells. e. An organism may or may not be made up of cells. 2. Which of the following are composed of cells working together? a. Only blood and muscle. b. Only blood and bone. c. Only muscle and bone. d. Blood, muscle and bone. e. None of the above. 3. Which of the following can become extinct? a. Plants, animals and microorganisms. b. Plants and animals, but not microorganisms. c. Only plants. d. Only animals. e. Only microorganisms. 4. In the food chain shown below, how is energy passed from organism to organism? a. As light energy. b. As chemical energy. c. As heat energy. d. As electrical energy. e. As energy of motion. 5. In a desert ecosystem, small mammals eat plants and snakes eat small mammals. What would probably happen to the amount of plant material if all the snakes suddenly died? At first, the amount of plant material would: a. not change because snakes do not eat plants. b. not change because other animals would move in to eat the small mammals. c. decrease because the number of surviving small mammals would increase. d. increase because there would be more room for plants to grow. e. decrease because the snakes protect the plants. GO TO QUESTION 6 >> The President and Fellows of Harvard College. NSF grant EHR Test Form 921.

2 6. In a forest, which of the following are decomposers, organisms that use waste and dead organisms for food? a. Only the trees. b. Only the squirrels. c. Only the mushrooms. d. Both the trees and the squirrels. e. Both the trees and the mushrooms. 7. What is skin made of? a. A single layer of flat thin cells. b. Many layers of flat thin cells. c. A single layer of different kinds of cells. d. Many layers of different kinds of cells. e. One very large thin cell that covers the body. 8. In a forest ecosystem (see picture below), squirrels eat plant material and foxes eat squirrels. What would probably happen to the amount of plant material in this ecosystem if all the foxes suddenly died? At first, the amount of plant material would: a. not change because foxes do not eat plants. b. not change because other animals would move in to eat the squirrels. c. decrease because the number of surviving squirrels would increase. d. increase because there would be more room for plants to grow. e. decrease because foxes protect the plants. GO TO QUESTION 9 >> The President and Fellows of Harvard College. NSF grant EHR Test Form 921.

3 9. Infectious diseases are often caused by: a. allergies. b. vitamin deficiencies. c. chemical spills. d. germs. e. drugs. 10. Why does Henry start to breathe faster when he exercises? The extra oxygen: a. helps his muscles to use more energy. b. helps him to release sweat. c. stops urine from being produced to balance the water lost through sweat. d. helps him to hold excess water until he can get to a bathroom. e. stops him from overheating. 11. Given the food chain shown below, what energy would be available to the wolf? a. All of the energy from the Sun, grass and deer. b. All of the energy from the Sun and grass, minus the energy in the deer. c. All of the energy transferred from the Sun to the grass. d. Only the energy contained in the grass. e. Some of the energy transferred from the Sun to the grass to the deer. 12. Which of the following limit the number of organisms an ecosystem can support? a. Only water. b. Only minerals. c. Only sunlight. d. Only water and sunlight. e. Water, minerals and sunlight. GO TO QUESTION 13 >> The President and Fellows of Harvard College. NSF grant EHR Test Form 921.

4 13. In the picture below, which parts make up a desert ecosystem? a. Only the cactus. b. Only the sand. c. Only the cactus and the sand. d. The cactus, sand and sunlight. e. A desert is not an ecosystem. 14. In a forest ecosystem foxes feed mostly on a variety of birds and rodents (small furry mammals). What would probably happen to the foxes if a flood destroyed one type of rodent? The foxes would: a. eat other rodents and birds. b. eat berries. c. eat insects. d. die. e. move elsewhere. 15. The most likely reason that Maria has a cold is that she was: a. outside in the cold air. b. not wearing a sweater. c. infected with a virus. d. outside with wet hair. e. in sunlight for too long. 16. The flu virus has most likely spread because: a. humans are slowly being exterminated. b. it keeps adapting to new environments. c. flu virus wants to infect people everywhere. d. the virus is smarter, faster and stronger than most people. e. overcrowding and pollution keep it alive and contagious The President and Fellows of Harvard College. NSF grant EHR Test Form 921.

5 17. Cells inside the human body get energy from: a. circulating oxygen in the blood. b. breaking down sugars that come from food. c. breaking down sugars that they make themselves. d. giving off carbon dioxide. e. giving off oxygen. 18. Blindness can be caused by damage to which of the following? a. Only the eyes. b. Only the brain. c. Only the spinal cord. d. Either the eyes or the brain. e. Either the brain or the spinal cord. 19. During a year, the size of the population of deer in a forest is most affected by: a. only the amount of rain. b. only the amount of sunlight. c. only the height of the trees. d. both the amount of rain and the height of the trees. e. both the amount of rain and sunlight. 20. If two plants reproduce sexually, what would the resulting baby plant look like? a. If the baby plant is female, it will look like its mother. b. If the baby plant is male, it will look like its father. c. The baby plant will be a combination of both parents. d. Its flowers will look like its mother s, and its stem will look like its father s. e. Plants never reproduce sexually. 21. Present day giraffes have long necks because: a. they stretch them to reach the trees for food. b. their ancestors adapted to have long necks over time. c. giraffes with the longest necks are the strongest and most perfect. d. their neck length increases their body temperature. e. their neck length increases their speed. 22. Why do squirrels from the same litter grow up to be different sizes? a. Only because they eat different amounts of food. b. Only because they want to be different sizes. c. Only because they inherited different genes. d. Both because they eat different amounts of food and inherited different genes. e. Both because they want to be different sizes and inherited different genes. 23. How would a scientist explain the presence of the hard, outer shell in lobsters? Lobsters: a. inherit their shell, which evolved over many generations. b. learn to grow an outer shell from their parents. c. discovered how to grow an outer shell and passed that on to their offspring. d. grow an outer shell in response to predators. e. prefer an outer shell to an internal skeleton. GO TO QUESTION 24 >> The President and Fellows of Harvard College. NSF grant EHR Test Form 921.

6 24. A pond ecosystem is best defined as: a. only the animals that live in the pond. b. only the plants that live in the pond. c. only the water in the pond. d. both the living and the non-living things in and around the pond. e. both the animals and the plants that live in and around the pond. 25. Which of the following is not made up of cells? a. Skin b. Blood c. Water d. Bacteria e. Lettuce The President and Fellows of Harvard College. NSF grant EHR Test Form 921.

7 LIFE SCIENCE SURVEY TEST For some questions, there may be more than one correct answer. However, each question has only one best answer. Choose the single best answer from the five choices for each question. 1. During a year, the size of the population of deer in a forest is most affected by: a. only the amount of rain. b. only the amount of sunlight. c. only the height of the trees. d. both the amount of rain and the height of the trees. e. both the amount of rain and sunlight. 2. Cells inside the human body get energy from: a. circulating oxygen in the blood. b. breaking down sugars that come from food. c. breaking down sugars that they make themselves. d. giving off carbon dioxide. e. giving off oxygen. 3. Why do squirrels from the same litter grow up to be different sizes? a. Only because they eat different amounts of food. b. Only because they want to be different sizes. c. Only because they inherited different genes. d. Both because they eat different amounts of food and inherited different genes. e. Both because they want to be different sizes and inherited different genes. 4. Given the food chain shown below, what energy would be available to the wolf? a. All of the energy from the Sun, grass and deer. b. All of the energy from the Sun and grass, minus the energy in the deer. c. All of the energy transferred from the Sun to the grass. d. Only the energy contained in the grass. e. Some of the energy transferred from the Sun to the grass to the deer. 5. In a forest, which of the following are decomposers, organisms that use waste and dead organisms for food? a. Only the trees. b. Only the squirrels. c. Only the mushrooms. d. Both the trees and the squirrels. e. Both the trees and the mushrooms. GO TO QUESTION 6 >> The President and Fellows of Harvard College. NSF grant EHR Test Form 922.

8 6. Why does Henry start to breathe faster when he exercises? The extra oxygen: a. helps his muscles to use more energy. b. helps him to release sweat. c. stops urine from being produced to balance the water lost through sweat. d. helps him to hold excess water until he can get to a bathroom. e. stops him from overheating. 7. Present day giraffes have long necks because: a. they stretch them to reach the trees for food. b. their ancestors adapted to have long necks over time. c. giraffes with the longest necks are the strongest and most perfect. d. their neck length increases their body temperature. e. their neck length increases their speed. 8. The most likely reason that Maria has a cold is that she was: a. outside in the cold air. b. not wearing a sweater. c. infected with a virus. d. outside with wet hair. e. in sunlight for too long. 9. If two plants reproduce sexually, what would the resulting baby plant look like? a. If the baby plant is female, it will look like its mother. b. If the baby plant is male, it will look like its father. c. The baby plant will be a combination of both parents. d. Its flowers will look like its mother s, and its stem will look like its father s. e. Plants never reproduce sexually. 10. In the food chain shown below, how is energy passed from organism to organism? a. As light energy. b. As chemical energy. c. As heat energy. d. As electrical energy. e. As energy of motion. 11. Which of the following is not made up of cells? a. Skin b. Blood c. Water d. Bacteria e. Lettuce The President and Fellows of Harvard College. NSF grant EHR Test Form 922.

9 12. Which of the following limit the number of organisms an ecosystem can support? a. Only water. b. Only minerals. c. Only sunlight. d. Only water and sunlight. e. Water, minerals and sunlight. 13. How would a scientist explain the presence of the hard, outer shell in lobsters? Lobsters: a. inherit their shell, which evolved over many generations. b. learn to grow an outer shell from their parents. c. discovered how to grow an outer shell and passed that on to their offspring. d. grow an outer shell in response to predators. e. prefer an outer shell to an internal skeleton. 14. A pond ecosystem is best defined as: a. only the animals that live in the pond. b. only the plants that live in the pond. c. only the water in the pond. d. both the living and the non-living things in and around the pond. e. both the animals and the plants that live in and around the pond. GO TO QUESTION 15 >> The President and Fellows of Harvard College. NSF grant EHR Test Form 922.

10 15. In a forest ecosystem (see picture below), squirrels eat plant material and foxes eat squirrels. What would probably happen to the amount of plant material in this ecosystem if all the foxes suddenly died? At first, the amount of plant material would: a. not change because foxes do not eat plants. b. not change because other animals would move in to eat the squirrels. c. decrease because the number of surviving squirrels would increase. d. increase because there would be more room for plants to grow. e. decrease because foxes protect the plants. 16. Which of the following can become extinct? a. Plants, animals and microorganisms. b. Plants and animals, but not microorganisms. c. Only plants. d. Only animals. e. Only microorganisms. 17. Infectious diseases are often caused by: a. allergies. b. vitamin deficiencies. c. chemical spills. d. germs. e. drugs. GO TO QUESTION 18 >> The President and Fellows of Harvard College. NSF grant EHR Test Form 922.

11 18. The flu virus has most likely spread because: a. humans are slowly being exterminated. b. it keeps adapting to new environments. c. flu virus wants to infect people everywhere. d. the virus is smarter, faster and stronger than most people. e. overcrowding and pollution keep it alive and contagious. 19. In a desert ecosystem, small mammals eat plants and snakes eat small mammals. What would probably happen to the amount of plant material if all the snakes suddenly died? At first, the amount of plant material would: a. not change because snakes do not eat plants. b. not change because other animals would move in to eat the small mammals. c. decrease because the number of surviving small mammals would increase. d. increase because there would be more room for plants to grow. e. decrease because the snakes protect the plants. 20. In the picture below, which parts make up a desert ecosystem? a. Only the cactus. b. Only the sand. c. Only the cactus and the sand. d. The cactus, sand and sunlight. e. A desert is not an ecosystem. 21. Blindness can be caused by damage to which of the following? a. Only the eyes. b. Only the brain. c. Only the spinal cord. d. Either the eyes or the brain. e. Either the brain or the spinal cord The President and Fellows of Harvard College. NSF grant EHR Test Form 922.

12 22. In a forest ecosystem foxes feed mostly on a variety of birds and rodents (small furry mammals). What would probably happen to the foxes if a flood destroyed one type of rodent? The foxes would: a. eat other rodents and birds. b. eat berries. c. eat insects. d. die. e. move elsewhere. 23. Which of the following are composed of cells working together? a. Only blood and muscle. b. Only blood and bone. c. Only muscle and bone. d. Blood, muscle and bone. e. None of the above. 24. What is skin made of? a. A single layer of flat thin cells. b. Many layers of flat thin cells. c. A single layer of different kinds of cells. d. Many layers of different kinds of cells. e. One very large thin cell that covers the body. 25. Which statement below best describes the relationship between an organism and its cells? a. An organism is a container that has cells inside of it. b. An organism is a container that has cells covering it. c. An organism is one big cell with other cells inside of it. d. An organism is made up of one or more cells. e. An organism may or may not be made up of cells The President and Fellows of Harvard College. NSF grant EHR Test Form 922.

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14 Grades 5 8 Life Science Tests The tests in this section contain items related to 17 of the grades 5 8 standards in life science from the NRC's National Science Education Standards (NSES); below are the standards as stated in the NSES. 5 8 Life Science Standard 1: "Living systems at all levels of organization demonstrate the complementary nature of structure and function. Important levels of organization for structure and function include cells, organs, tissues, organ systems, whole organisms, and ecosystems." 5 8 Life Science Standard 2: "All organisms are composed of cells the fundamental unit of life. Most organisms are single cells; other organisms, including humans, are multicellular." 5 8 Life Science Standard 3: "Cells carry on the many functions needed to sustain life. They grow and divide, thereby producing more cells. This requires that they take in nutrients, which they use to provide energy for the work that cells do and to make the materials that a cell or an organism needs." 5 8 Life Science Standard 4: "Specialized cells perform specialized functions in multicellular organisms. Groups of specialized cells cooperate to form a tissue, such as a muscle. Different tissues are in turn grouped together to form larger functional units, called organs. Each type of cell, tissue, and organ has a distinct structure and set of functions that serve the organism as a whole." 5 8 Life Science Standard 5: "Disease is a breakdown in structures or functions of an organism. Some diseases are the result of intrinsic failures of the system. Others are the result of damage by infection by other organisms." 5 8 Life Science Standard 6: "Every organism requires a set of instructions for specifying its traits. Heredity is the passage of these instructions from one generation to another." 5 8 Life Science Standard 7: "The characteristics of an organism can be described in terms of a combination of traits. Some traits are inherited and others result from interactions with the environment." 5 8 Life Science Standard 8: "All organisms must be able to obtain and use resources, grow, reproduce, and maintain stable internal conditions while living in a constantly changing external environment." 1

15 5 8 Life Science Standard 9: "Regulation of an organism's internal environment involves sensing the internal environment and changing physiological activities to keep conditions within the range required to survive." 5 8 Life Science Standard 10: "Behavior is one kind of response an organism can make to an internal or environmental stimulus. A behavioral response requires coordination and communication at many levels, including cells, organ systems, and whole organisms. Behavioral response is a set of actions determined in part by heredity and in part from experience." 5 8 Life Science Standard 11: "An organism's behavior evolves through adaptation to its environment. How a species moves, obtains food, reproduces, and responds to danger are based in the species' evolutionary history." 5 8 Life Science Standard 12: "A population consists of all individuals of a species that occur together at a given place and time. All populations living together and the physical factors with which they interact compose an ecosystem." 5 8 Life Science Standard 13: "Populations of organisms can be categorized by the function they serve in an ecosystem. Plants and some micro-organisms are producers they make their own food. All animals, including humans, are consumers, which obtain food by eating other organisms. Decomposers, primarily bacteria and fungi, are consumers that use waste materials and dead organisms for food. Food webs identify the relationships among producers, consumers, and decomposers in an ecosystem." 5 8 Life Science Standard 14: "For ecosystems, the major source of energy is sunlight. Energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis. That energy then passes from organism to organism in food webs." 5 8 Life Science Standard 15: "The number of organisms an ecosystem can support depends on the resources available and abiotic factors, such as quantity of light and water, range of temperatures, and soil composition. Given adequate biotic and abiotic resources and no disease or predators, populations (including humans) increase at rapid rates. Lack of resources and other factors, such as predation and climate, limit the growth of populations in specific niches in the ecosystem." 2

16 5 8 Life Science Standard 16: "Biological evolution accounts for the diversity of species developed through gradual processes over many generations. Species acquire many of their unique characteristics through biological adaptation, which involves the selection of naturally occurring variations in populations. Biological adaptations include changes in structures, behaviors, or physiology that enhance survival and reproductive success in a particular environment." 5 8 Life Science Standard 17: "Extinction of a species occurs when the environment changes and the adaptive characteristics of a species are insufficient to allow its survival. Fossils indicate that many organisms that lived long ago are extinct. Extinction of species is common; most of the species that have lived on the earth no longer exist." The items are identical on both test forms, but arranged in different sequences so that the forms can be used as a pretest/post-test pair (either form may be used as the pretest). Either form can be used by itself as a diagnostic test. The 5 8 tests are intended for use primarily with 7th and 8th grade students. The tests can also be administered to any persons who possess at least a 7th grade reading level fluency in English. NOTE: Administering the tests to anyone with less than the indicated minimum reading level may result in invalid test results due to the test performing more as a reading comprehension test rather than as a science test. 3

17 Item # Form 921 Item # Form Text of item Std. 1 Which statement below best describes the relationship between an organism and its cells? a. An organism is a container that has cells inside of it. b. An organism is a container that has cells covering it. c. An organism is one big cell with other cells inside of it. d. An organism is made up of one or more cells. e. An organism may or may not be made up of cells. Which of the following are composed of cells working together? a. Only blood and muscle. b. Only blood and bone. c. Only muscle and bone. d. Blood, muscle and bone. e. None of the above. Which of the following can become extinct? a. Plants, animals and microorganisms. b. Plants and animals, but not microorganisms. c. Only plants. d. Only animals. e. Only microorganisms Correct response & percent 2 responding correctly D: 41% (n = 837) D: 39% (n = 217) A: 41% (n = 132) Commentary 3 Less than half of middle school students correctly understood the relationship between an organism and its cell(s). The most common wrong answer given was option E. 20% of students who answered incorrectly responded with E. The largest proportion of incorrect responses was for option A (60% of incorrect responses). This choice may mean that students are not familiar with bone as a living tissue, made up of cells. The most common incorrect response to this question was D, which was chosen by 64% of students who answered incorrectly. Apparently, the extinction of plants and microorganisms is not well understood by middle school students. 1 These test items are valid psychometrically and represent standards commonly included in middle school life science curricula. 2 Students were selected randomly in classes to be a nationally representative sample of all grades 7 and 8 students in U.S. public and private schools. The sample number (n) is included for each item because the number of students per item varied considerably. 3 The commentary reflects item response patterns. Common misconceptions in life science are discussed in a separate section. 4

18 In the food chain shown below, how is energy passed from organism to organism? (See diagram in item on test.) a. As light energy. b. As chemical energy. c. As heat energy. d. As electrical energy. e. As energy of motion. In a desert ecosystem, small mammals eat plants and snakes eat small mammals. What would probably happen to the amount of plant material if all the snakes suddenly died? At first, the amount of plant material would: a. not change because snakes do not eat plants. b. not change because other animals would move in to eat the small mammals. c. decrease because the number of surviving small mammals would increase. d. increase because there would be more room for plants to grow. e. decrease because the snakes protect the plants. In a forest, which of the following are decomposers, organisms that use waste and dead organisms for food? a. Only the trees. b. Only the squirrels. c. Only the mushrooms. d. Both the trees and the squirrels. e. Both the trees and the mushrooms B: 52% (n = 144) C: 72% (n = 259) C: 53% (n = 98) Slightly more than onehalf of the incorrect responders (51%) chose A, which may suggest that students do not understand how photosynthesis transforms light energy to chemical energy. 53% of students responding incorrectly chose A, suggesting that the relationship between plants and carnivores in an ecosystem is not clear to many students. A large majority (58%) of students who answered incorrectly chose option E, suggesting that students cannot identify decomposers in a forest ecosystem. 5

19 What is skin made of? a. A single layer of flat thin cells. b. Many layers of flat thin cells. c. A single layer of different kinds of cells. d. Many layers of different kinds of cells. e. One very large thin cell that covers the body. In a forest ecosystem (see picture in item on test), squirrels eat plant material and foxes eat squirrels. What would probably happen to the amount of plant material in this ecosystem if all the foxes suddenly died? At first, the amount of plant material would: a. not change because foxes do not eat plants. b. not change because other animals would move in to eat the squirrels. c. decrease because the number of surviving squirrels would increase. d. increase because there would be more room for plants to grow. e. decrease because foxes protect the plants. Infectious diseases are often caused by: a. allergies. b. vitamin deficiencies. c. chemical spills. d. germs. e. drugs D: 54% (n = 102) C: 54% (n = 98) D: 90% (n = 144) 60% of the incorrect responses were option B. This choice may be attributed to how skin cells appear to students when examined through a microscope. The common wrong answer was option A, chosen by 60% of students responding incorrectly. This pattern reinforces the idea that students are not aware of the interconnections between organisms in an ecosystem. Interestingly, while very few students did not answer this question correctly, option A was chosen by one-half of the students who chose an incorrect answer. 6

20 Why does Henry start to breathe faster when he exercises? The extra oxygen: a. helps his muscles to use more energy. b. helps him to release sweat. c. stops urine from being produced to balance the water lost through sweat. d. helps him to hold excess water until he can get to a bathroom. e. stops him from overheating. Given the food chain shown below, what energy would be available to the wolf? (See diagram in item on test.) a. All of the energy from the Sun, grass and deer. b. All of the energy from the Sun and grass, minus the energy in the deer. c. All of the energy transferred from the Sun to the grass. d. Only the energy contained in the grass. e. Some of the energy transferred from the Sun to the grass to the deer. Which of the following limit the number of organisms an ecosystem can support? a. Only water. b. Only minerals. c. Only sunlight. d. Only water and sunlight. e. Water, minerals and sunlight. In the picture below (see picture in item on test), which parts make up a desert ecosystem? a. Only the cactus. b. Only the sand. c. Only the cactus and the sand. d. The cactus, sand and sunlight. e. A desert is not an ecosystem A: 41% (n = 128) E: 43% (n = 222) E: 60% (n = 98) D: 72% (n = 144) 57% of students who responded incorrectly chose option E. This choice suggests that many students do not realize the role oxygen plays in cellular metabolism. The most common wrong answer given was A (chosen by 73% of students who were incorrect); this choice suggests that the transfer of energy in a food chain is not completely grasped by many students. 51% of the students who were incorrect chose option D. Some middle school students are apparently not aware of the role of minerals in an ecosystem. When students responded incorrectly, the large majority did not include sunlight as part of the ecosystem (60% of incorrect responses were option C). 7

21 In a forest ecosystem foxes feed mostly on a variety of birds and rodents (small furry mammals). What would probably happen to the foxes if a flood destroyed one type of rodent? The foxes would: a. eat other rodents and birds. b. eat berries. c. eat insects. d. die. e. move elsewhere. The most likely reason that Maria has a cold is that she was: a. outside in the cold air. b. not wearing a sweater. c. infected with a virus. d. outside with wet hair. e. in sunlight for too long. The flu virus has most likely spread because: a. humans are slowly being exterminated. b. it keeps adapting to new environments. c. flu virus wants to infect people everywhere. d. the virus is smarter, faster and stronger than most people. e. overcrowding and pollution keep it alive and contagious. Cells inside the human body get energy from: a. circulating oxygen in the blood. b. breaking down sugars that come from food. c. breaking down sugars that they make themselves. d. giving off carbon dioxide. e. giving off oxygen. ndness can be caused by damage to which of the following? a. Only the eyes. b. Only the brain. c. Only the spinal cord. d. Either the eyes or the brain. e. Either the brain or the spinal cord A: 71% (n = 98) C: 58% (n = 439) B: 36% (n = 98) B: 14% (n = 383) D: 65% (n = 132) 76% of students who answered incorrectly chose option E. These students may have oversimplified the effect of the loss of a single prey species in an ecosystem with a diversity of such species. 69% of students answering incorrectly chose option A. This choice may reflect their exposure to a common "folk" notion, i.e., you get a cold simply from being chilled. The small sample of students who responded to this item may contribute to the apparent difficulty of the question, but the low correct response rate also may indicate a lack of student understanding concerning how environments affect viruses. Options C, D and E were equally attractive to students who answered incorrectly. The nature of cellular respiration is apparently unfamiliar to middle school students. Interestingly, the incorrect options draw roughly equal proportions, reinforcing the notion that this topic is not commonly taught, or at least not addressed in detail. This item addresses how the brain supports a wide range of functions, including sight. While the majority of students answered correctly, most students without complete comprehension chose option A (57% of the incorrect responses). 8

22 During a year, the size of the population of deer in a forest is most affected by: a. only the amount of rain. b. only the amount of sunlight. c. only the height of the trees. d. both the amount of rain and the height of the trees. e. both the amount of rain and sunlight. If two plants reproduce sexually, what would the resulting baby plant look like? a. If the baby plant is female, it will look like its mother. b. If the baby plant is male, it will look like its father. c. The baby plant will be a combination of both parents. d. Its flowers will look like its mother s, and its stem will look like its father s. e. Plants never reproduce sexually. Present day giraffes have long necks because: a. they stretch them to reach the trees for food. b. their ancestors adapted to have long necks over time. c. giraffes with the longest necks are the strongest and most perfect. d. their neck length increases their body temperature. e. their neck length increases their speed E: 53% (n = 98) C: 55% (n = 132) B: 32% (n = 144) Option D was the most common incorrect response, with 63% of students with incorrect responses choosing that option. These students may have missed the connection between sunlight and plant growth. Many students do not realize that some plants can reproduce sexually: More than 85% of incorrect responses were option E. The most frequent incorrect response to this question reflects common misconceptions about evolution. 84% of students who answered incorrectly chose option A, a choice that is very common among students and mirrors the Lamarckian theory of evolution. 9

23 y do squirrels from the same litter grow up to be different sizes? a. Only because they eat different amounts of food. b. Only because they want to be different sizes. c. Only because they inherited different genes. d. Both because they eat different amounts of food and inherited different genes. e. Both because they want to be different sizes and inherited different genes. How would a scientist explain the presence of the hard, outer shell in lobsters? Lobsters: a. inherit their shell, which evolved over many generations. b. learn to grow an outer shell from their parents. c. discovered how to grow an outer shell and passed that on to their offspring. d. grow an outer shell in response to predators. e. prefer an outer shell to an internal skeleton. A pond ecosystem is best defined as: a. only the animals that live in the pond. b. only the plants that live in the pond. c. only the water in the pond. d. both the living and the non-living things in and around the pond. e. both the animals and the plants that live in and around the pond D: 68% (n = 129) A: 50% (n = 100) D: 42% (n = 132) Slightly more than half (51%) of students who answered incorrectly chose option C. This choice may suggest that students do not completely understand how heredity and environment can interact to affect individual organisms. While option E was the most commonly selected incorrect response (40% of students who answered incorrectly), the other incorrect responses were also attractive to students. This pattern again illustrates many students lack of understanding of evolution and adaptation. There is a belief among some students that organisms make a deliberate choice on how they will change. Many students apparently define an ecosystem only as comprising living organisms: 72% of the incorrect responses were option E. 10

24 25 11 Which of the following is not made up of cells? a. Skin b. Blood c. Water d. Bacteria e. Lettuce 1 C: 55% (n = 837) Interestingly, option E was the most frequent erroneous response, with 50% of students answering incorrectly choosing lettuce, and slightly fewer choosing option D (40%). This pattern may be due, at least in part, to the common textbook references to skin cells and blood cells, allowing the fairly easy elimination of these choices. More understanding is required to rule out bacteria and lettuce. Major Misconceptions in Grades 5 8 Life Science Listed below are some student life science misconceptions. The list is not intended to be exhaustive, but rather a summary of some of the more common prior ideas we identified from our analysis of the student response patterns to the items on the tests. Traits developed within an organism s lifetime can be passed down genetically to its offspring. Plants cannot reproduce sexually. All sexual reproduction involves physical mating. The size and shape of the cells that comprise an organism are directly correlated with the size and shape of the organism (e.g. an elephant s cells are larger than those of a mouse; plant cells are rectangular, animal cells are round). Food is a requirement for growth, but not the source of matter for growth. When a cell is in interphase, it is asleep. Living things contain cells, but are not composed of them. Males of all species are larger, stronger and faster than the females. This pattern extends to genetics: A male trait is dominant and stronger than either a female trait or a recessive trait. Plants eat soil as their food source. 11

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26 Extinction of a species is very rare. This idea encompasses the entire history of Earth and leads to the corollary notion that most of the species alive today have always been on Earth. Extinction of species is mostly caused by humans. Respiration and breathing are the same thing. The following resources are useful for additional background information about students' science misconceptions: Driver, R., Pupil as Scientist?, Philadelphia: Open University Press (1983). Driver, R., et al., Making Sense of Secondary Science, Philadelphia: Open University Press (1994). Anderson, D. L., Fisher, K. M., & Norman, G. J. (2002). Development and evaluation of the conceptual inventory of natural selection. Journal of Research in Science Teaching, 39(10): Klymkowsky, M. W. & Garvin-Doxas, K. (2008). Bioliteracy-bci conceptual assessment for better learning in the biological sciences. Retrieved from < Ozkan, O., Tekkaya, C., & Geban, O. (2004). Facilitating conceptual change in students' understanding of ecological concepts. Journal of Science Education and Technology, 13(1): Webb, P. & Boltt, G. (1990). Food chain to food web: a natural progression? Journal of Biological Education, 24(3):