Students are introduced to the characteristics of life, including organization, biochemistry, and homeostasis.
There are several possible options for how to present the topics.
- Start with the question “Are we alone in the universe, and how will we identify life if we find it?” To begin to figure this out, we should understand the properties of life, and how it arose on earth (Topics: Life, Chemistry, Cell). The importance of water as the solvent in which life originated motivates an exploration of the range of precipitation and temperature conditions of different environments (biomes). This leads to an investigation of how life works, especially how structure relates to function across a range of conditions (Topics: SA/V, Gradients, Membrane Transport, Thermoregulation, Osmoregulation).
- Start with the question “Is there life on Mars?” Use the question “Why is water so important in the search for signs of life on Mars?” to motivate an exploration of “Why is liquid water so important for life?” (Topics: Life, Chemistry). A study of the Miller-Urey experiment can be used to introduce or review the elements of experimental design. From macromolecules, transition to cell structure (which are made of macromolecules; Topic: Cell). Tie back to life on Mars – “If humans visit Mars, what would we need to survive?” (Topics: SA/V, Gradients, Membrane Transport, Thermoregulation, Osmoregulation).
- Start with images of terrestrial (cold vs. hot) and aquatic (fresh vs. salt? tropical vs. polar?) animals from contrasting environments. What traits do they have, and why? Differences between the pairs motivate study of homeostasis (Topics: SA/V, Gradients, Membrane Transport, Thermoregulation, Osmoregulation). The characteristics in common lead to an exploration of the traits that are necessary for life (Topics: Life, Cell, Chemistry).