Nonvascular plants that live today include liverworts, mosses, and hornworts-collectively and informally known as bryophytes. Nonvascular Plants Were the First Plants on Earth The diverse plant life on Earth-consisting of nearly 400,000 species-can be divided into three broad categories based on biological characteristics: nonvascular, seedless vascular, and seed plants.
So while today most plants on Earth grow from seeds, because of the many and varied adaptations of nonvascular plants, they continue to thrive in moist habitats across the globe. This also means that they cannot reach large sizes, and often remain low-growing. However, instead of pollen, the male gametes of nonvascular plants are self-motile, requiring water-even in small amounts such as a light morning dew-to disperse and actively swim to the female gamete.įinally, the fertilized diploid egg, remaining attached to the gametophyte, grows via mitosis to form a new sporophyte.īryophytes are also unique in that they lack extensive vascular tissue-with no true roots, leaves or stems-and therefore rely on diffusion through cells to distribute nutrients and water. These spores then grow via mitosis to form the gametophyte.įertilization in non-vascular plants still occurs using male and female gametes. One major characteristic of the bryophytes is that they lack seeds and reproduce using spores produced by the diploid sporophyte. Bryophyte gametophytes are typically larger and live longer than their sporophyte counterparts which depend upon them for nourishment and protection. Unlike other plants, bryophytes have life cycles dominated by gametophytes. This process is called the alternation of generations. Like all plants, bryophytes alternate between haploid gametophyte-here, the main body of the moss-and diploid sporophyte stages during their life cycles. These plants are often collectively called bryophytes. Today, this group includes three phyla of small, herbaceous plants: mosses, liverworts, and hornworts-which include many aquatic species. While seed plants are the most widespread on Earth today, nonvascular plants were once one of the key features of the terrestrial landscape. Some parts of seedless plants can be used as food.Plant life on Earth consists of nonvascular, seedless vascular, and seed plants. It is used as low cost fuel in some areas of the world. Horsetails have been used for polishing objects, sharpening tools, and scouring cooking utensils. They have a big tip at the end that produces spores. They are found in the tropics.ġ0 Horsetails They have a jointed, hollow center stem. Ferns, ground pines, spike mosses, and horsetails are in this group.Ĩ Ferns This is the largest group of seedless vascular plants.įerns have fronds – these are leaves that have spores on the underside.ĩ Club Mosses Ground pine and spike mosses are in this group. These plants can grow larger and thicker because they have a way to move water and nutrients to all plant cells. They are a pioneer species – the first organisms to grow in new or disturbed environments.Īll of these plants reproduce by spores but they have vascular tissues. Mosses are usually among the first plants to grow in new or disturbed environments. They can grow in very little amounts of soil. These plants can withstand long, dry periods. They usually must live in damp areas, but there are a few types of moss that can live in the desert.Ĥ Liverworts These are rootless plants with flattened, leaf like bodies and very small rhizoids.ĥ Hornworts Small with flattened bodies and only have 1 chloroplast in each cell.
There are 3 types of seedless nonvascular plants: mosses, liverworts, and hornworts.ģ Mosses Mosses grow on tree trunks and rocks or the ground. They do not have roots, instead they have rhizoids that anchor them to the soil. They have stalks that look like stems and green leaf like growths. These plants are usually only a few cells thick and not very large. Presentation on theme: "Chapter 9.2 Seedless Plants."- Presentation transcript:
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