1.Compare and contrast vegetative features (i.e., features not directly involved
ID: 8918 • Letter: 1
Question
1.Compare and contrast vegetative features (i.e., features not directly involved in reproduction) of bryophytes and gymnosperms. For as many differences as possible, explain how the features of gymnosperms allow them to colonize dry environments better than bryophytes can.
2.Describe the growth of a highly branched, large oak tree from an embryo within an acorn. (Note that the cotyledons in an oak seedling remain belowground when an oak seedling germinates.) Emphasize which meristems are involved in the oak’s development at different points in time, where these meristems are located, and how each affects the final form of the oak. You do not need to discuss what causes the acorn to germinate. You do not need to trace the development of every single root and branch, but trace the development of roots and branches to two orders of branching (i.e., a branch attached to a branch attached to the main axis and a root attached to a root attached to the main root).
Explanation / Answer
1.Bryophytes are small, very simple land plants which may be upto 4 cm in length.Bryophytes include mosses, liverworts, and hornworts.Due to their structural simplicity they form the premiere species during ecological succession. Bryophytes lack true roots or true leaves, they lack proper vascular system, and they do not produce hard tissues for structural support. The absence of these structures that are important for growth on land greatly restricts the potential size of bryophytes, which, unlike algae, are terrestrial rather than aquatic.The ferns represent the largest group of spore-bearing vascular plants. Gymnosperms, also called ferns , on the other hand have true roots, leaves, and vascular tissues, and they produce hard tissues for support. The presence of these structures enable ferns to grow to the size of small trees. Gymnopserms are better adapted to the drying conditions of terrestrial life than bryophytes because of the presence of vascular tissues, megaspore protected by one tegument and presence of double fertilization and dominant, independent sporophyte.however gymnopserns still depended on water as a medium for the movement of sperm to the egg. This dependence on water during a critical stage of their life cycle restricts the ecological range of ferns to relatively moist habitats.
2. Meristems are the group of cells which exhibit the capacity to divide.The apical meristem is a group of cells that retain the ability to cell divisions thus forming new cells continuously as the plant grows. Both shoots and roots develop from apical meristems, undifferentiated cells clustered at their tips. In roots, a root cap is also produced, which protects the meristem as it grows through the soil. The lateral organs of the shoot i.e.leaves and axillary branches, have a superficial origin in shoot apical meristems. Lateral roots are derived from pericycle cells deep within the root.The primary growth is responsible for growth in height. Woody plants have secondary growth, in that they have a special lateral meristem called the vascular cambium, that allows the growth in diameter. The cambium makes large cells early in the year, and smaller ones later in the summer, and this cycling of large and small cells is responsible for the appearance of growth rings in the wood, usually 1 "ring" per year. So the answer is that they grow taller, then get bigger around. The male meristem has both vegetative and reproductive development phases whereas the female only develops reproductively. Activity of the male meristem ceases once the inflorescence is fully developed. Shoots bearing female inflorescences retain an apical vegetative meristem which continues to develop.
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