GEOG 1 San Jose State University The Biosphere Questionnaire

Topic: The Biosphere

In this course, we cannot go very deeply into biology or ecology, but we shall touch on a few key ideas. This week we will concentrate on the material sources of life, and the material significance of life. I’ll keep it brief, for those of you recovering from Spring Break.

Watch: Plants Affect the Atmosphere

https://ca.pbslearningmedia.org/resource/nves.sci.earth.atmosphere/plants-affect-the-atmosphere/ (链接到外部网站。)

Watch: NOVA: Earth From Space | Lightning Produces Nitrates

https://ca.pbslearningmedia.org/resource/nves.sci.earth.nitrate/lightning-produces-nitrates/ (链接到外部网站。)

Besides a source of energy and water, life depends on the presence of a few other elements, particularly nitrogen. Most living things cannot get this nitrogen directly from the air; they get it indirectly from specialized microbes, as well as from lightning. Another direct link between the biosphere and the atmosphere that most of us are unaware of. Most life on Earth gets its energy from the sun, either directly or indirectly, via an evolved set of processes called photosynthesis and respiration. Carbon dioxide is required, and water and oxygen are released, globally, on a massive scale. Living things therefore are key determinants of just how much carbon is in the atmosphere, and so they are largely responsible for the sort of climate that has evolved on this planet. In order to fully understand climate, we have to understand life. We can change the direction that the world climate takes in the future, one way or another, depending on how well we understand and treat living things.

Homework 9:

1. What primary components of Earth’s atmosphere do plants modify through photosynthesis and respiration?

1. Describe the processes of photosynthesis and respiration. How do they relate to one another?

1. How have plants contributed to making Earth a habitable planet?

1. Why does the Amazon rainforest have such a dramatic impact on the atmosphere?

1. On average, how many lightning strikes occur on Earth each second?

1. How does lightning produce nitrate?

1. Why is nitrate important for living things?

1. How does nitrate produced in clouds end up in human bodies?