Gymnosperms have seeds but not fruits or flowers. Gymnosperms developed during the Paleozoic Era and became the dominant seed plant group during the early Mesozoic Eraas shown in Figure 1. The ancestors of gymnosperms were some now-extinct type of heterosporous fern or related group.
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Gymnospermany vascular plant that reproduces by means of an exposed seed, or ovule —unlike angiospermsor flowering plants, whose seeds are enclosed by mature ovaries, or fruits. Taxonomists recognize four distinct divisions of extant nonextinct gymnospermous plants— ConiferophytaCycadophytaGinkgophytaand Gnetophyta —with 88 genera and more than 1, species distributed throughout the world. Gymnosperms were dominant in the Mesozoic Era about
Gymnosperms are seed plants adapted to life on land; thus, they are autotrophic, photosynthetic organisms that tend to conserve water. They have a vascular system used for the transportation of water and nutrients that includes roots, xylem, and phloem. This term comes from the fact that the ovules and seeds of gymnosperms develop on the scales of cones rather than in enclosed chambers called ovaries.
Gymnosperms - Pinophyta. Next Lecture. Four major groups within the gymnosperms are usually recognized - these sometimes each considered its own phylum Cycadophyta, Ginkgophyta, Gnetophyta, Pinophyta.
The gymnospermsalso known as Acrogymnospermae are a group of seed-producing plants that includes coniferscycadsGinkgoand gnetophytes. The name is based on the unenclosed condition of their seeds called ovules in their unfertilized state. The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants angiospermswhich are enclosed within an ovary.
Gymnosperms are sporophyte dominant. This means that the largest, longest lived stage is the diploid sporophyte. The gametophyte stage is highly reduced in gymnosperms.
Gymnosperms are flowerless plants that produce cones and seeds. The term gymnosperm literally means "naked seed," as gymnosperm seeds are not encased within an ovary. Rather, they sit exposed on the surface of leaf-like structures called bracts. Gymnosperms are vascular plants of the subkingdom Embyophyta and include conifers, cycads, ginkgoes, and gnetophytes.
Gymnosperms are seed-bearing vascular plants, such as cycads, ginkgo, yews and conifers, in which the ovules or seeds are not enclosed in an ovary. The word "gymnosperm" comes from the Greek word gymnospermosmeaning "naked seeds". Gymnosperm seeds develop either on the surface of scale or leaf-like appendages of cones, or at the end of short stalks.
Seed plant introduction: Origin and evolution of the seed habit The seed habit is the most complex and evolutionary successful method of sexual reproduction found in vascular plants. Today, seed plants, gymnosperms "Nacktsamer", ca. Most of this diversity is accounted for by the angiosperms and Charles Darwin described the rapid rise and early diversification within the angiosperms during the Cretaceous time as 'an abdominable mystery' see 'angiosperm seed evolution'. The seed plants have an adaptive advantage, occur in a wide variety of habitats and dominate today's flora.