The+Diversity+of+Plants

__Nonvascular plants: __ Not as wide common or as widespread in their distribution as vascular plants because of their life function, such as photosynthesis and reproduction, require an open source of water. Nonvascular plants are limited to moist habitats by streams and rivers, or in areas such as a tropical rainforest. __Alternations of generations: __ All plants have a life cycle including an alternation of generations between a diploid sporophyte and a haploid gametophyte. Nonvasuclar plants include the only plants that have a dominant gametophyte generation. Sporophytes attach to gemetophytes and take in water and other substances. Antheridium – The male reproductive structure in which sperm are produced. Archegonium- The female reporductive structure in which eggs are produced.  __Adapatation in Bryophyta __: There are two divisions: mosses and bryophytes. Bryophytes are the most familiar of the non-vascular plant divisions. Mosses are the small plants with leafy stems. Mosses have rhizoids, colorless multi cellular structures, which help anchor the stem to the soil. Mosses grow in a wide variety of habitats. __Adapations in Hepaticophyta __: Another division is the liverworts, or hepaticophytes. Usually grow in clumps or masses in moist habitats. A liverwort is categorized as either thallose or leafy. The body of a thallose is called a thallus. Leafy liverworts usually grow close to the ground and are common in tropical jungles. __Adaptations in Anthocerophyta __: These are the smallest division, consisting of only a hundred species. Commonly known as hornworts, which are similar to liverworts, as they both have a thallose body. A unique feature of hornworts are the presence of one to several chloroplasts in each cell of the sporophyte. __Origins of Nonvascular Plants __: Evidence suggests that liverworts were the first land plants. They first appeared in rocks in the early Paleozoic era more than 440 million years ago. Both nonvascular and vascular planes probably share a common ancestor. __What is a non-seed vascular plant? __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;"> The obvious difference in the presence of vascular tissue. Vascular tissue is tube-like and carries water and sugars through the system. Vascular plants are able to adapt to changes in the availability of water. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Alteration of generations __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: The spore-producing vascular sporophyte is dominant and larger than the gametophyte. The sporophyte does not depend on the gametophyte for water or nutrients. Spore bearing leaves form a compact cluster called the strobilus. The spores are released from the strobilus and grow the form gametophytes. A fern gametophyte is called a prothallus. Antheridia and archegonia develop on the gametophyte. Sperm are released from the antheridia. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Adaptations in Lycophyta __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Leafy stems resemble moss gametophytes and their reproductive structure is club or a spike shaped. The sporophyte generation of the lycophytes is dominant. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Adaptations on Arthrophyta __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Only about 15 species in existence, which are the entire genus //Equisetum//. They are found in areas of damp soil, they contain cilia which gives them a rough-like feature. Arthrophyte spores are produced in the strobili, that form at the tips. The stem structure is ribbed and hollow, and appears jointed. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Adaptations in the Pterophyta __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: First appeared nearly 375 million years ago, and are more abundant than the club mosses or horse tails. They can be found in both moist and dry areas, and can range from being very small to being very big. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Fern Structures __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: It is the sporophyte generation of the fern that has roots, stems and leaves. The gametophyte of most ferns is thin, and is independent of the sporophyte. The thick, underground stem is called the rhizome, which contains starch filled cells for storage. Ferns are the first of the vascular plants to have evolved leaves with branching veins of vascular tissue. The branched veins also transfer water and nutrients to the cells. Fern spores are produced in structures called sporangia. Clusters of sporangia form a structure called the sorus. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;"> __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Origins of Non-Seed Vascular Plants __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Large tree sized lycophytes, anthrophytes, and pterophytes, were extremely abundant in the moist, warm forests. They used to be as tall as 30 meters but are now much smaller and less wide spread. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">What is a Seed Plant? __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Seeds in which reduced sporophyte plants are enclosed within a protective coat, such as fruit, or carried on the scales of a cone. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Seed Plants Produce Spores __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: The male gametophyte developed inside a structure called a pollen grain. The female gametophyte is called the ovule. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Fertilization Reproduction __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Fertilization does not require a continuous film of water, as required by non vascular and non-seed vascular plants. Because they do not need a continuous film of water, they can reproduce in a wide variety of habitats. Embryos are the earliest stage of development in plants, which include one or more cotyledons. The cotyledons usually store or absorb the food. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Advantages of Seeds __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Food supply is enclosed in a tough protective coat, and has food supply. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Diversity of Seed Plants __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Some plants develop on woody strobili called cones. This group of plants are referred to as gymnosperms. They do not have their seeds protected. Flowering plants are called angio-sperms, their seeds are enclosed in the fruit. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Adaptations in Cycadophyta __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Only about 100 species exist in the tropics and sub-tropics. They have male and female reproductive systems on separate plants. The male system includes cones and pollen grains, the female system include cones that produce ovules. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Adaptations in Ginkophyta __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: All ginkgoes are cultivated trees, so they are not found in the wild. They are similar to cycads in reproduction. Ginkgoes are often planted in urban areas because they tolerate smog and pollution. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Adaptations in Gnetophyta __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: They are mostly found in deserts such as Africa and South America. They contain only three genera, which are //Gnetum//, //Ephedra, Welwitschia//. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Adaptations in Coniferophyta __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: The conifers are trees and shrubs with needle-like or scale-like leaves. The reproductive structure of most conifers are produced in cones. Most conifers have male and female cones on separate trees. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Evergreen __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Conifers: Their leaves last for more than one year Evergreen leaves usually have a heavy coating of cutin, that helps reduce water loss. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Deciduous Trees Lose their Leaves __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Deciduous plants drop all their leaves each fall, or when water is scarce. They drop leaves to retain moisture in the trunk. They must remain dormant during fall and winter. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Adaptations in Anthophyta __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: They have more than 250,000 identified species, and have roots stems and leaves, but produce flowers and form seeds enclosed in a fruit. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Fruit Production __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Fruits often aid in the dispersal of seeds. They are carried through animals eating them, and the seeds survive the digestive system. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Monocots and Dicots __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Monocotyledons have one seed leaf and dicotyledons have two seed leafs. About 65,000 species of monocots have been identified such as grasses, orchids and lilies. About 185,000 dicots have been identified, such as shrub trees, vegetables, and garden flowers. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Life Spans of Anthophytes __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Annual plants live for only one year or less. They sprout from seeds, grow, reproduce, and die in a single growing season. These are plants such as corn, wheat, peas, beans, and squash. Biennial plants last for two years. They develop large storage fruits such as carrots beans, and peanuts. Over the winter, the above-ground portion dies, but the roots survive. Perennials live for several years, producing flowers and seeds periodically, usually once each year. __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Origins of Seed Plants __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">: Seed plants appeared about 360 million years ago during the Paleozoic era. Most members of the ginkgophyta died out along with many organisms during the mass extinction about 65 million years ago. According to fossil evidence, first conifers emerged about 250 million years ago. Anthophytes appeared about 140 million years ago in the Mesozoic era.
 * __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">The Diversity of Plants __**
 * <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Non-Seed Vascular Plants **<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">
 * <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">Seed Plants **<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">