IB_1108_L21_PlantCirc

Pre-Lab Questions When did vascular plants evolve? How was this timeline uncovered? Vascular plants were discovered around 425 million years ago. The potentially oldest known vascular plant is a plant fossil that dates back to the Silurian period. The timeline was uncovered by analyzing fossil records and to uncover how old they are. How does a vascular system help a plant to grow bigger? Vascular plants have evolved stem that are made of tissues and lignin. The lignin allows the plant to become stiff and be able to support the plant structure as it grows taller and bigger. Because of lignin the plant is able to grow farther off the ground to get more air, light and nutrients. In 2 - 3 sentences, discuss how gas exchange affects transpiration. Gas exchange in plants is when plants release O2 as a waste product of photosynthesis while simultaneously receiving CO2 during photosynthesis. Transpiration is related to this because for transpiration to occur pores in the stomata need to be open. When the pores are open the transpiration rate increase and when the pores are closed the transpiration rate decreases. Directly affected by this, if the pours are closed no photosynthesis occurs and no gas exchange occurs. Describe one way in which plants can adapt to changes in water supply. During transpiration, plants release water vapor into the air through the stomata. If the water supply decreases plants can adapt to this by not opening the pores in the stomata to decrease transpiration. If the water supply increases plants can adapt to this by opening the pores in the stomata to increase transpiration. Why is water referred to as the “universal solvent?” Water is the universal solvent because it has a polar arrangement of its hydrogen and oxygen atoms. This allows water wherever it is to dissolve a variety of substances. Water is able to dissolve substances more than any other liquid. Why is a water droplet shaped like a sphere? Although water droplets can be easily deformed, they tend to default to a spherical shape because of surface tension. There are cohesive forces on the surface layer that pull water into tiny spheres. In essay form, discuss three adaptations plants have made to thrive in different environments. There are numerous adaptations plants have made to thrive in their environments. The adaptions can be physical and be noticed by the human scenes of sight and smell. For example, fruits that are eaten by large animals depend on the animals to spread their seeds through waste production. To attract more animals, many of these fruits evolved into sweeter brighter fruit plants. Plants also make chemical adaptions that cannot be noticed by appearance. For example, the Callery pear tree is a species of pear tree that can be found in Georgia. Every spring the tree blooms beautiful flowers that smell absolutely horrid. Although the tree does not attract humans because of its horrid stench, it does attract flies and insects that spread pollen around. The horrid stench is an adaptation made overtime to attract flies. Plants can also make adaptations to changes in how their organelle/organ systems function. For example, when changes in a plants water supply occurs, plants will increase or decrease the opening of the pores in the stomata to control how much water vapor it releases into the atmosphere. Experiment 1: Functionality of the Water Column Experimental Results Draw what you saw in the digital slides in the boxes provided below. Label the xylem and phloem. Show how far the dye traveled in the submerged and air-dried celery stalks by drawing on the images below. Post-Lab Questions How far did the dye travel in the celery which was submerged in water for 15 minutes? How far did it travel in the piece which was air-dried for 15 minutes? The dye traveled about halfway up the celery that was submerged in water for 15 minutes. The dye did not travel very far up the celery that was air-dried for 15 minutes. There are indicators showing it traveled but the dye did not go very far. In which celery stalk was the water column broken? The celery stalk that air dried for 15 minutes. Experiment 2: Water Movement in Flowers Post-Lab Questions Record your hypothesis from Step 3 here. Be sure to address how the dye will affect the flower over time, and why.  If the fresh/exposed part of the carnation flower is remains submerged under red dyed water for 48 hours, the flowers stem, petals and other parts will have traces of red dye. This is because the red dye water will travel up the flowers stem against the force of gravity and be delivered to other parts of the flower. Additionally, I hypothesize the traces of red dye will transform the flowers physical appearance from white to red. Show where the dye traveled in the flower after 24 and 48 hours and explain how it got there in the space provided. What factors can influence the rate of transpiration in flowers? Factors that influence the rate of transpiration in flowers are humidity, wind, sunlight, and temperature.