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Practice Test 1 - Middle School Life Science

20 questions. Answer them in any order, then submit to see your score and every explanation.

  1. Which step in reproduction is directly prevented by removing the stigma?
  2. A river section is dammed, reducing flooding downstream. Evidence of ecosystem change: average number of flood days per year decreases from 12 to 2. Population data in the downstream floodplain: cottonwood seedlings decrease from 500 to 120; mature cottonwood trees remain about the same (40 to 39); deer increase from 25 to 40. Which argument best explains the population shift using the evidence and reasoning that links reduced flooding to the population response? Arguments must be evidence-based.
  3. A class model shows how photosynthesis adds matter to living things. The model has: - an arrow labeled energy input from the Sun to the plant - two arrows labeled matter enters from the environment into the plant (from air and from water in soil) - a label inside the plant: "matter becomes part of new plant material (leaves and stems)" Which evidence from the model best shows matter entering the organism? Choose ONE.
  4. Two simplified models show that reproduction type affects genetic outcomes. Model 1 (asexual): 1 parent organism produces 3 offspring. Model 2 (sexual): 2 parent organisms produce 3 offspring. Which comparison of offspring is supported by the models, using evidence about similarity or variation?
  5. A student compares growth of the same type of seedlings in two soils for 5 weeks. The only changed condition is soil type: Soil A vs Soil B. Height is measured with the same ruler each week. Which explanation best matches the growth pattern in the line graph using evidence (trend over time) rather than a single point?
  6. Two ecosystem models are described below. Interaction patterns can be compared across ecosystems using evidence from the models. Ecosystem Model 1 (Pond): mosquitoes lay eggs; mosquito larvae are eaten by small fish; adult mosquitoes are eaten by bats. Ecosystem Model 2 (Park): caterpillars eat leaves; caterpillars are eaten by birds; birds are eaten by hawks. A student claims: "These ecosystems cannot be compared because one has insects and the other has birds." Which evidence best supports evaluating the claim?
  7. Two groups of the same plant species have different inherited traits: Group A is a tall-growing variety and Group B is a short-growing variety (genetic factors). They are grown in two environments: high water and low water (environmental factors). Use the evidence in the table to choose the best explanation. Evidence (average height after 6 weeks): - Tall variety: 30 cm in high water; 18 cm in low water - Short variety: 20 cm in high water; 12 cm in low water Which explanation best describes the interaction between genes and environment on growth, using the evidence?
  8. Which statement describes the main reproductive function of the berries?
  9. A grassland experienced an ecosystem change: a wildfire burned most of the area. Scientists compared populations one month before the fire and six months after. Population data (estimated individuals in a 1 km2^2 area): - Grasses: before 90,000; after 40,000 - Rabbits: before 220; after 90 - Hawks: before 18; after 7 Which statement is supported by the evidence and includes reasoning that links the change to the population response? Arguments must be evidence-based.
  10. Food webs show interconnected feeding relationships in an ecosystem. In the food web model, arrows show the direction of energy transfer. Model: - Seagrass (producer) → Sea urchin (consumer) - Seagrass (producer) → Fish (consumer) - Sea urchin (consumer) → Octopus (consumer) - Fish (consumer) → Octopus (consumer) Which statement about the food web model is supported?
  11. In a model of photosynthesis, arrows show carbon dioxide entering the leaves from the air and water entering the roots from the soil. A separate arrow labeled light energy points to the leaves. The model labels plant sugars stored in the stem as an outcome inside the plant. Which source provides matter that enters the plant and becomes part of the stored sugars, based on evidence from the model?
  12. Fossil layers are ordered by time (Layer 1 oldest → Layer 6 youngest). Fossils found: Layer 1: Sponge; Layer 2: Sponge, Snail; Layer 3: Sponge, Snail; Layer 4: Snail; Layer 5: Snail; Layer 6: Snail, Seal. Fossils provide evidence of extinction and appearance by showing last occurrences and first appearances. Which claim about extinction is incorrect based on the evidence?
  13. Model: A diagram shows a student holding an ice cube. In a close-up of the fingertip skin, a labeled cold receptor is shown in contact with cooled skin tissue. A label says "signal begins." A later panel shows the student dropping the ice cube (response). Which prediction about detection is supported if the cold receptor fails to work?
  14. Use the simplified organism model: Immune system responds to pathogens in the body (arrow to "pathogen"), and the Circulatory system transports immune cells to different body areas (arrow from circulatory to immune response sites). The model shows systems affect one another and organism function depends on system interaction. Which interaction supports organism function?
  15. Fossil layers show changes in life forms over time. A student studies layers ordered from older (bottom) to younger (top): - Layer 4 (oldest): ammonite fossils - Layer 3: ammonites + dinosaur bone fragments - Layer 2: dinosaur bone fragments only - Layer 1 (youngest): bird fossils Which claim about life change is incorrect based on the evidence in these fossil layers?
  16. A diagram shows embryo images of a bat and a whale at the same limb-development stage. Both embryos have highlighted forelimb buds with similar positions and a tail. Later, the bat develops wings and the whale develops flippers. Embryological similarities can suggest common ancestry. Which statement about embryological ancestry is supported?
  17. Use the model to answer the question. The model shows biological organization occurs in levels. Which claim about organization is incorrect based on evidence from the model?
  18. Look at the embryo images in the diagram: Species 1 (fish), Species 2 (chicken), and Species 3 (human) are shown at Stage 1 (early) and Stage 2 (later). In Stage 1, all three embryos have highlighted pharyngeal pouches (throat grooves) and a tail. In Stage 2, the embryos look more different from each other. Embryological similarities can suggest common ancestry. Which inference about ancestry is supported by the embryo images and the highlighted shared structures at the same stage?
  19. A student says, "Because the offspring in this inheritance model has striped feathers, it must have gotten stripes from the environment, not from its parents." In the model, Parent 1 has striped feathers, Parent 2 has solid feathers, and the offspring has striped feathers. The arrows show genetic information passed from parents to offspring. Which statement about inheritance is supported by the model and evidence?
  20. Fossil layers show changes in life forms over time. A student says: "Because mammals are found in the top (youngest) layer, the fossil record shows that life always changes from simple to complex in a straight line." The layers are ordered from older (bottom) to younger (top): - Layer 4 (oldest): worm burrow traces - Layer 3: worm traces + fish fossils - Layer 2: fish fossils only - Layer 1 (youngest): mammal fossils Which claim about these fossil layers is incorrect based on the evidence?

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