FRQ: Plant Adaptations to Land
Charlotte Gaillet/ AP Biology B/ 18 week
Plant Adaptations on Land
Four Adaptations that aid the angiosperm plants to reproduce on land are the casing of seeds, the alternation of generations, the dispersion of the seeds by natural forces, and the vascular qualities of the plant. The casing of the seeds allow the fertilized embryos to stay protected and safe until they have the ability to take root in healthy soil. The casings of seeds could be a hard outer shell or fruit. The main purpose of the seed casings are their ability to protect the embryos. The alternation of generations is the reproductive cycle of plants. This means that throughout some stages of the plants life they go through a haploid stage and through other stages of the plants life they go through a diploid stage. The alternation of generations is important to the plants ability to reproduce on land because the diploid embryo is no longer one hundred percent dependent on the haploid gametophyte. The seeds had to discover new ways to disperse along the land environment because they could no longer depend on the bodies of water to disperse the seeds. The seeds are now dipersed in natural forces such as the wind, animal's fur, water, and structure of plants. Lastly, the plants developed structures that helped them to become vascular and create a respiratory system to breath on land.
Structures the Aid in Support and the Fight Against Dehydration
Structures that aid in the support of the plants on land are the Shoots, longer roots, a stomata, and secondary metabolites. The shoots allow the plant to grow taller to reach more sunlight. The shoots are the longest part on the plants stem. The longer roots help aid the plant to grow deeper into the ground to recieve more nutrients and to be more stable against natural forces such as wind. The stomata allows the plant to have a place for the gases of cellular respiration to exchange. This means that the carbon dioxide is taken in and then converted to oxygen which will be released into the atmosphere.The stomata provides support for the plant because it helps to keep the plant healthy by taking in the nutrients the plants need and releasing the wastes that the plants do not need. The secondary metabolites protect and support the plant by shielding the plant from harmful light rays and predators. The waxy cuticle, meristems, pholem, and xylem help to protect the plant from dehydration. The waxy cuticle covers the leaves and makes it harder for water to evaporate from the leaves. The water that isn't evaporated is stored in the shoots, roots, and leaves. The xylem works to distribute water evenly throughout the plant making sure that each structure of the plant receives enough water to survive. The meristem is the tissue of the plant that allows the shoot of the plant to grow taller. The taller the shoot is, the more nutrients the shoot can store. This means that the taller plants have the ability to store more water and not become dehydrated. The pholem is a tissue that helps retrieve all the necessary nutrients out of the water that the plant takes in. It is important to fight of dehydration because the pholem works to take in water distribute its nutrients to all different parts of the plants.