Tutor profile: Ashley H.
Subject: Environmental Science
The water cycle describes the movement of water on, in, and above the Earth. Earth's water is always in movement and is always changing states, from liquid to vapor to ice and back again. Believe it or not, trees and plants even play a role through transpiration. Can you explain a trees role in the process of transpiration in the water cycle?
Trees entire into the water cycle when they take up groundwater and runoff through their roots. Some of this water is returned through the air through the process of transpiration. Trees use the water they take up in a process called photosynthesis and, as a result of this process, water vapor is released from the leaves of a tree and goes back into the water cycle.
While in the Galapagos, Charles Darwin noticed variations in species that would eventually support his theory of evolution. For example, Darwin noticed that the finches on the Galapagos Islands were all very similar, but had slightly different beak shapes. He predicted that these finch species had all evolved from one species of finch found on the mainland. Explain what natural selection is and how it might have played a role in the finches developing different beak shapes over time as they moved to different islands.
Natural selection is a process in which individuals with more favorable traits are better able compete, survive, and reproduce. Therefore they are able to pass on those favorable trait to the next generation. In the case of Darwin's finches, the one mainland species of finch had to adapt to food sources on the different islands it moved to. For example, lets say the mainland finch ate both insects and nuts because they were both available on the mainland. Therefore their beaks were a mixture of wide and tough to crack nuts and narrow to dig out insects. However, once they moved to a new island, only nuts were available. This would mean that the finches with beaks that were slightly wider and tougher where able to get more food and survive better than the finches with slightly narrower beaks. This means, that through natural selection, the finches with the wide, tough beaks survived, reproduced and passed on the wide/tough beak trait to their offspring. Eventually, over a long period of time, the mainland finches adapted into a different species of finch with only wide, tough beaks.
Subject: Fire Science
Many forest ecosystems, particularly in the Western United States, experience infrequent fire disturbances. For example, subalpine forests in the Rocky Mountain front range historically experience a fire disturbance every 150 - 300 years. Since these fire disturbances have been happening for centuries, trees have adapted this fire regime. Name one adaptation of a tree that allow it to regenerate after a fire disturbance.
Some trees, such as lodgepole pine, have developed serotinous cones as an adaptation to regular, yet infrequent fire disturbances. Serotinous cones are held together buy a sticky substance (resin) and held tightly closed while on the tree. However, once a fire rolls through the forest, these cones heat up, the resin melts, and the cones drop their seeds on to the nitrogen rich, recently burned soil.
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