Gymnosperms are seed plants that have adapted to land existence; as such, they are autotrophic, photosynthetic creatures that save water. They have a vascular system (used for water and nutrient transfer) that includes roots, xylem, and phloem. The term gymnosperm refers to a “naked seed,” which is the primary distinction between gymnosperms and angiosperms, two separate groupings of seed plants. The word derives from the fact that gymnosperm ovules and seeds develop on the scales of cones rather than in enclosed chambers known as ovaries. On the evolutionary scale, gymnosperms are older than angiosperms. They appear in the fossil record far earlier than angiosperms. The many environmental adaptations that gymnosperms have indicate a step on the route to the most successful (diversity-wise) clade, as will be detailed in following sections (monophyletic branch).
Gymnosperms:
Gymnosperms, unlike angiosperms, do not produce blooms or fruit. They are thought to be the earliest vascular plants to appear on land, circa 245-208 million years ago, during the Triassic Period. Gymnosperm land colonisation was possible by the development of a vascular system capable of delivering water throughout the plant. There are about a thousand gymnosperm species now, divided into four major divisions: Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta.
What does Gymnosperm mean?
A gymnosperm is any vascular plant that reproduces through an exposed seed, or ovule, as opposed to angiosperms, or flowering plants, whose seeds are encased by mature ovaries, or fruits. Many gymnosperm seeds (literally, “naked seeds”) are borne in cones and are not visible until the plant matures. Taxonomists acknowledge four separate divisions of extant (non extinct) gymnospermous plants: Pinophyta, Cycadophyta, Ginkgophyta, and Gnetophyta, with 88 genera and over 1,000 species scattered worldwide.
Wind is the primary source of pollination and dissemination. These are mostly medium to large trees, with a few shrub species thrown in for good measure. The Sequoia is a gymnosperm, and it is one of the tallest tree species.
The plant body differs in that it is separated into leaves, stems, and roots. The needle-like leaves have a thick cuticle and depressed stomata, as found in conifers. This feature aids in lowering water loss owing to transpiration.
The taproot system is the root system found in gymnosperms. Some plants, such as Pinus, have their roots associated with fungi and create mycorrhiza. While the roots of a few other species, such as the Cycas plant, are in the form of specialised roots known as coralloid roots and are connected with nitrogen-fixing cyanobacteria. These plants are vascular as well, having both xylem and phloem present.
When did Gymnosperm arise:
Gymnosperms were prevalent during the Mesozoic Era (approximately 252.2 million to 66 million years ago), when some current families evolved (Pinaceae, Araucariaceae, Cupressaceae). Although gymnosperms have been steadily supplanted by more recently developed angiosperms during the Cretaceous Period (approximately 145 million to 66 million years ago), they are still successful in many parts of the planet and occupy huge swaths of the Earth’s surface. Conifer woods, for example, cover large areas of northern temperate zones, and gymnosperms frequently flourish at higher latitudes than angiosperms.
Characteristics of gymnosperms:
The visible component of the plant body (i.e., the developing stem and branches) symbolises the sporophyte, or asexual, generation rather than the gametophyte, or sexual, generation in all living gymnosperm groupings. A sporophyte typically has a stem with roots and leaves that houses the reproductive organs.
Gymnosperms, as vascular plants, have two conducting tissues: xylem and phloem. The xylem transports water and minerals from the roots to the rest of the plant, as well as providing structural support. The phloem transports sugars, amino acids, and organic nutrients produced in the leaves to the plant’s non photosynthetic organs.
Male pollen cones, known as microstrobili in most gymnosperms, possess shortened leaves known as microsporophylls. Microsporangia, or pollen sacs, are carried on the undersides of microsporophylls. The number of microsporangia in a conifer can range from two to hundreds in some cycads. Cells within the microsporangia divide chemically to form haploid microspores.
Conclusion:
Gymnosperms have evolutionary significance and certain distinguishing characteristics. The absence of flowers and the presence of naked, open seeds distinguishes them. Because they lack flowers, fruits are likewise lacking in this group of plants. Gymnosperms, unlike angiosperms, do not produce blooms or fruit. They are thought to be the earliest vascular plants to appear on land, circa 245-208 million years ago, during the Triassic Period. Gymnosperm land colonisation was possible by the development of a vascular system capable of delivering water throughout the plant. There are about a thousand gymnosperm species now, divided into four major divisions: Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta.