Unit Conclusion

Unit A Conclusion

In this unit you have investigated the equilibrium between matter and energy in the biosphere in relation to the photosynthetic and cellular respiration processes of living organisms. Through the study of the hydrologic cycle and the biogeochemical cycles of important elements, you have examined the nature of water and seen other forms of matter as the building blocks for life. Also, you have explored the role of living organisms in maintaining all biogeochemical cycles. The impact of human activities on the state of the equilibrium of Earth’s atmospheric composition has also been explained.

When asked to answer the first essential questions of this unit, you will be able to explain that most of the energy used in the biosphere comes from the Sun and is either stored or re-emitted back into space. As well, you will capably explain how the capture of energy in the biosphere can be considered to be a balance between photosynthetic- and cellular-respiration processes. You will also be able to describe how useable stored energy found in producers is eventually lost as heat through life-sustaining processes of consumers, like the growth and repair of tissues, or through the process of decomposition.

As for the third concept in this unit, in Module 1 you will have seen that matter is cycled through both the biotic and abiotic components of the biosphere. You will be able to summarize and explain the carbon-oxygen, nitrogen, and phosphorus biogeochemical cycles. You will also be able to explain the properties of water, such as hydrogen bonding, and explain how these allow it to play a critical role in the general cycling of matter in the biosphere.

Finally, when asked about the last essential questions of the unit, you will understand that the biosphere’s air composition is influenced by all living organisms. You will be able to explain how the equilibrium between gas exchanges in photosynthesis and cellular respiration controls the planet’s atmospheric composition. You will also be able to describe how human activities, like fossil fuel combustion and deforestation, can disrupt the balance between photosynthetic and cellular respiration processes in the biosphere. And you will describe what impact these human activities have on the global climate. Once you have completed this unit, you will be able to explain the causes and consequences of global warming.