Since then, she has continued in this vein of research. As Jennifer puts it, "Plants are wonderfully in tune with their environments, so there are many proxies or signals that we can obtain from fossil plants.
We can work out the temperature they lived in, the atmospheric environment, and the carbon dioxide concentration. Jennifer uses stomata as indicators of carbon dioxide levels at different points in Earth's history. Experiments help her figure out the exact relationship between stomata and carbon dioxide.
Using growth chambers, she can simulate the temperature, light level, and atmospheric conditions common at different times in the deep past and at different places on Earth. So even when it's subzero in Chicago, her seedlings might feel as though they are growing in sunny California or in the humid swamps of the Jurassic. Studying how modern plants respond to these environments helps Jennifer understand how the characteristics of long extinct plants were affected by their environments.
Leaves with microscopic mouths Global greenhouse. Overview of Data Collection and Analysis Methods. Week 1. Envision an environmental difference that might affect stomata density and formulate an hypothesis about which way you would expect stomata density to vary and WHY. Next, decide on a place anywhere within about 10 minutes walking time where you intend to collect leaf samples in the environmental types of interest, and go and get them. Bring your leaf samples back to lab and count their stomata densities see Methods for Obtaining Stomata Impressions below.
Lastly, submit your co-authored research proposal with your partner. This document should fit on one page and should contain three sections according to the Guidelines for Stomata Research Proposal below. Week 2. Next week, bring all of your data to class, finish counting stomata if you have not already have done so , and your instructor will help you with the statistical analyses, and computer graphics generation of your stomata data to test your hypothesis see Guidelines for Data Analysis below.
In addition, you should begin to produce your oral and written reports which are due the following week. Week 3. The entire lab period this week will be devoted to a symposium of presentations of your research results to your peers.
Also on this date, your co-authored written report is due see Guidelines for Written Reports below as well as your disk copy of your data see Guidelines for Data Management below. Your individually written critical review of this multiweek lab activity is due the following week see Guidelines for Reflective Reviews of Lab Activities below.
Methods for Obtaining Stomata Impressions. Tools for Assessment of Student Learning Outcomes: Below is a graphic to illustrate the relationships among the laboratory objectives, activities, and assessment instruments.
Click on this graphic to see the complete system diagram for this lab activity. Below we explain how we have designed these assessment instruments for our classes. Keep in mind that: there must be a clear and unbroken network of links that map the objectives to the activities, to the assessment instruments, and then back to the objectives, and this map as well as all details of how assessment proceeds must be completely revealed to the students beforehand - students will attempt to perform only and exactly those tasks upon which they will be assessed.
Scoring Rubric for Questions for Thought. We ask our students to submit written answers to any 4 of the questions. Students should use their texts or any other written references to answer these questions - but they must cite the complete and exact source of any text, web, or other outside material that they used. We strongly recommend that you read out loud to your students your course policy on plagiarism which should be in your syllabus , and if you do not have one GET ONE!
Each citation of a research article or book should have: Author s. Title of paper. Volume: Pages. Each citation of an internet resource page should have: Author s if known. This is part of the hyrdrogeologic cycle. Land plants are a crucially important part of it. Dilcher also said less transpiration may mean the shade of an old oak tree may not be as cool of a respite as it used to be. But the hydrogeologic cycle is complex.
It's hard to predict how changing one thing will affect other aspects. We would have to see how these things play out. While it is well known that long-lived plants can adjust their number of stomata each season depending on growing conditions, little is known about the long-term structural changes in stomata number or size over periods of decades or centuries.
That model suggests that a doubling of today's carbon dioxide levels -- from parts per million to ppm -- will halve the amount of water lost to the air, concluding in the second paper that "plant adaptation to rising CO 2 is currently altering the hydrological cycle and climate and will continue to do so throughout this century.
Dilcher and his Dutch colleagues say that a drier atmosphere could mean less rainfall and therefore less movement of water through Florida's watersheds. The Florida Everglades depend heavily on the slow, steady flow of groundwater from upstate.
The siphoning of that water to development has raised questions about the future of the Everglades as a national resource. The project received support from Utrecht University's High Potential research program. Materials provided by Indiana University.
Note: Content may be edited for style and length. Science News.
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