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A. Diversity of Life
By the end of 8th grade, students should know that:
- One of the most general distinctions among organisms is between plants, which use sunlight to make their own food, and animals, which consume energy-rich foods.
- Animals and plants have a great variety of body plans and internal structures that contribute to their being able to make or find food and reproduce.
- Similarities among organisms are found in internal anatomical features, which can be used to infer the degree of relatedness among organisms.
- For sexually reproducing organisms, a species comprises all organisms that can mate with one another to produce fertile offspring.
- All organisms, including the human species, are part of and depend on two main interconnected global food webs.
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B. Heredity
By the end of 8th grade, students should know that:
- In some kinds of organisms, all the genes come from a single parent, whereas in organisms that have sexes, typically half of the genes come from each parent.
- In sexual reproduction, a single specialized cell from a female merges with a specialized cell from a male.
- New varieties of cultivated plants and domestic animals have resulted from selective breeding for particular traits.
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C. Cells
By the end of 8th grade, students should know that:
- All living things are composed of cells, from just one to many millions, whose details usually are visible only through a microscope.
- Cells repeatedly divide to make more cells for growth and repair.
- Within cells, many of the basic functions of organisms such as extracting energy from food and getting rid of waste are carried out.
- About two thirds of the weight of cells is accounted for by water, which gives cells many of their properties.
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D. Interdependence of Life
By the end of 8th grade, students should know that:
- In all environments freshwater, marine, forest, desert, grassland, mountain, and others organisms with similar needs may compete with one another for resources, including food, space, water, air, and shelter.
- Two types of organisms may interact with one another in several ways: They may be in a producer/consumer, predator/prey, or parasite/host relationship.
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E. Flow of Matter and Energy
By the end of 8th grade, students should know that:
- Food provides molecules that serve as fuel and building material for all organisms.
- Over a long time, matter is transferred from one organism to another repeatedly and between organisms and their physical environment.
- Energy can change from one form to another in living things.
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F. Evolution of Life
By the end of 8th grade, students should know that:
- Small differences between parents and offspring can accumulate (through selective breeding) in successive generations so that descendants are very different from their ancestors.
- Individual organisms with certain traits are more likely than others to survive and have offspring.
- Many thousands of layers of sedimentary rock provide evidence for the long history of the earth and for the long history of changing life forms whose remains are found in the rocks.
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