Imagine that a researcher has discovered a 500-million-year-old leaf fossil from the Cambrian Period. He notices that the leaf had very few stomata compared to present-day leaves. What does this tell the researcher about atmospheric CO₂ levels during the Cambrian Period?

Question

Quizplus · Accepted Answer

Stomata are small openings on the surfaces of leaves that allow for gas exchange, including the intake of carbon dioxide (CO2) for photosynthesis. A lower number of stomata suggests that the plant did not need to open as many portals to collect the necessary CO2, implying that atmospheric CO2 levels were higher, making it easier for plants to obtain CO2 for photosynthesis.

Imagine That a Researcher Has Discovered a 500-Million-Year-Old Leaf Fossil