Unit 4: From Molecules to Organisms

All living things are made up of cells, which are the building blocks of life. In this lesson, students explore how scientists use the fossil record to track the increasing diversity and complexity of organisms on Earth by comparing ancient fossilized cells with modern organisms. Students investigate this phenomenon by comparing the complexity of modern-day prokaryotic cells with eukaryotic cells.

Once students have investigated the similarities among cells and the structures that make up eukaryotic cells, they then conduct an experiment to explore how cells extract energy from food through cellular respiration, comparing how much carbon dioxide (a product of cellular respiration) is produced by yeast when they consume different amounts of sucrose (sugar).

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Students use what they know about cellular structure and how cells extract energy from food molecules to investigate how the body is made up of smaller interacting systems that are made up of different combinations of cells. They do this by testing how the circulatory system of daphnia is affected by consumed sugar.