Anthocerophyta+6th+Period

ANTHOCEROPHYTA Anthocerophyta is a small phylum that consists of one species of plants known as hornworts. Hornworts are an interesting and unique species given that they are one of few species of plants with a phylum all their own. Their unique characteristics and evolutionary adaptations have allowed them to survive and make up the phylum of Anthocerophyta. ** CLASSES ** Anthocerophyta happens to be an extremely small phylum that contains only one species of plant, and therefore contains only one class of plants within the whole phylum. This class is known as Anthocerotopsida. Anthocerotopsida has only one species of plants, the hornworts.  **SPOROPHYTES AND GAMETOPHYTES **

Anthocerophyta (or hornworts) have sporophytes, just like all plants. In this phylum however, their sporophyte comes in the form of a long horn-like structure. Sporophytes are forms of plants that have been alternated over the generations to produce asexual spores. When looking at hornworts you can identify the sporophytes easily. They are the long horn- like structures protruding out of the gametophyte (the sexual form a plant that has formed and alternated over generations). Both sporophytes and gametophytes are haploids, meaning that they both have one set of homologous chromosomes. Sporophytes are made when the gametophyte produces male and female gametes that fuse together creating a diploid zygote that then develops into a sporophyte. Since Anthocerophyta has a dominant gametophyte, the sporophyte depends on the gametophyte its whole life for nutrition, making them embryophytes. 

**MONOCOTS ** When looking at the general overview of flowering plants, there are two main types of plant: monocotyledons (monocots) and Dicotyledons (dicots). Monocots have one cotyledon (or embryonic leaf) in the seed, have flowers have more than three petals, have roots that are adventurous and grow out throughout the soil, and have veins in all monocot leaves are parallel. Dicots have two cotyledons (or two embryonic leaves) in the seed, dicots have four or five petals, their roots grow and sprout from the radicle and are more controlled than the roots of a monocot, and their veins are not parallel, but reticulate. Horn worts have the distinct characteristic of parallel veins in their sporophytes. ** BRYOPHYTES ** Bryophytes, or non-vascular land plants are a type of land plant. A bryophyte is a small, herbaceous plant with leaves and stems that die down at the end to the soil level and have no stem above the ground. Bryophytes grow closely to one other and are packed into groups in patches of soil. Bryophytes are different from tracheophytes because of two different and important characteristics. The main difference between bryophytes and tracheophytes is that bryophytes are non-vascular plants where as tracheophytes are vascular plants. The second characteristic is that bryophytes never form xylem tissue during their life span. There are three different phyla of bryophytes. These phyla are the mosses (phylum Bryophyta), liverworts (phylum Marchantiophyta), and hornworts (phylum Anthocerotophyta). Of the three phyla of bryophytes, the greatest amount of species diversity is found in the mosses, with up to 15,000 species recognized. ** THE WAY ANTHOCEROTALES WORK **

VASCULAR VERSUS NON-VASCULAR Plants can be classified into two groups: vascular and non-vascular plants. Most plants have a vascular system that contains xylem and phloem. Xylem is made of non-living cells that help to transport water and nutrients throughout the plant. Phloem is a type of living cell that helps transport sugar that has been made in photosynthesis and makes sure that it gets spread throughout the plant. Having a vascular system is considered to be evolutionarily advanced, but it is not necessary for survival. Three phyla of plants don’t have a vascular system. These phyla are Hepatophyta, Bryophyta, and Anthocerophyta. This means that yes, phylum Anthocerophyta does not have a vascular system. ROOTS Most plants, mainly vascular plants, use roots to help anchor themselves into the ground and provide support. Roots though, are not just for support. They help to take in and provide essential nutrients for the plant. Roots have three parts to them: the root cap, the apical meristem, and the vascular cylinder. The vascular cylinder is where all of the xylem and phloem are kept. Therefore, only plants that have a vascular system have roots. This means that hornworts do not have any roots, but they actually have filamentous rhizoids. STEMS In plants, stems are used for many different purposes. Some plants have stems that conduct photo synthesis, or the process of turning sun light into energy. Others have stems that form a protective outer layer on the plant. Over all, stems are the bulk of the plant. They support the plant’s leaves and allow for transfer of nutrients and water throughout the plant. In hornworts, the stems go through two different types of growth. The primary growth makes the plant grow taller, and the secondary growth makes the stems grow wider. Anthocerophyta stems support the plant and its leaves since the plant doesn’t have real roots. LEAVES In all plant phyla, including Anthocerophyta, leaves are used for the photosynthetic process. They turn sunlight into sugar energy for the plant. This is why leaves are normally broad and flat, their shape allows for easy absorption of sunlight. Hornwort leaves are not much different. They are green because of chlorophyll in the cells which help to collect sunlight, and their leaves are open and exposed to the sun. ** EVOLUTIONARY SUCCESS ** Anthocerophyta is a very unique species, and it has survived natural selection because of its different combination of adaptations. Its lack of vascular system coupled with its unique system regarding sporophytes has allowed it to survive over the years. It also has another peculiar adaptation that has allowed it to survive all this time. Its sporophyte is contained in a long horn-like structure that the plant gets its name from. As this form of the sporophyte evolved over the years, it allowed for the survival of this one species of Anthocerophyta, the hornwort. This unique species is a survivor, despite the fact that is not very evolutionarily advanced, it has managed to survive and thrive in its habitat. ** RESOURCES ** [] []  @http://bryophytes.plant.siu.edu/index.html  @http://protein.bio.msu.ru/biokhimiya/contents/v72/full/72121675.html 