Essay by tutaj16High School, 12th gradeC+, November 2014

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A fern is a leafy, flowerless plant that grows in areas of high moisture. A fern is different from other vascular plants in that most vascular plants grow directly from seeds, while a fern grows from a spore, through an intermediate stage called a gametophyte. Angiosperm is a plant of a large group that comprises those that have flowers and produce seeds enclosed within a carpel, including herbaceous plants, shrubs, grasses, and most trees. Both species have their own life cycle.

In the life cycle of a fern, the role of a sporophyte is to produce haploid spores by meiosis. Spores are produced inside sporangia which grow in clusters within sori on the underside of a fern frond. When a spore lands on the ground it grows into a haploid gametophyte called a prothallus. In the life cycle of a flowering plant the diploid sporophyte produces haploid spores by meiosis within structures known as flowers.

Gametophyte develops usually from one type of spore in ferns (homosporous), while angiosperms are heterosporous. They produce two types of spores (male and female) within two types of sporangia. In ferns, the gametophyte (prothallus) is haploid, independent, photosynthetic and has rhizoids for anchoring and water absorption. It forms gametes inside gametangia reproductive organs) called archegonia and antheridia located on the undersurface of the thallus. In many species male and female organs grow on different prothalli. Fertilization gives a diploid zygote which grows by mitosis. Both gametophytes are nutritionally dependent on the sporophyte haploid. In a flowering plant Microspores (pollen grains) are the male spores. They form inside pollen sacs (microsporangia) of the anthers of stamens by meiosis of microsporocytes (microspore mother cells). Megaspores are female spores. They form inside the megasporangium within the ovule of a carpel by meiosis of megasporocytes. The microgametophyte is normally...