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The gymnosperms and angiosperms together constitute the spermatophytes or seed plants. The spermatophytes are subdivided into five divisions, the angiosperms and four divisions of gymnosperms: the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta).
- Gymnosperm Definition
- Examples of Gymnosperm
- Gymnosperm Life Cycle
- Related Biology Terms
- Quiz
Gymnosperms are a group of plants which produce seeds that are not contained within an ovary or fruit. The seeds are open to the air and are directly fertilized by pollination. “Gymnosperm”, from the Greek, gymnos, “naked” and sperma, “seed”, develop their seeds on the surface of scales and leaves, which often grow to form cone or stalk shapes, con...
Conifers
Conifers, in the division Pinophyta or Coniferophyta, are the most numerous of the gymnosperms; woody and with vascular tissue, these are cone bearing trees and shrubs. Conifers can be found growing in all parts of the world, although they most notably dominate the boreal forestsof the northern hemisphere. Many are adapted to cold climatic conditions, with downward facing branches, which help to shed snow, and specific biochemical properties that provide resistance to freezing. Examples of co...
Cycads
The appearance of the cycads (division Cycadophyta) typically constitutes a single, stout, cylindrical, woody trunk and a crown of large, hard and stiff, evergreen compound leaves, which grow directly from the trunk in a rosette formation. The cycads are dioecious, meaning that each individual plant is either all male or all female. The cycads are partly xerophyte, which means they are adapted to survive in areas with very little liquid water, although their distribution largely centers aroun...
Gnetophytes
The gnetophyta are distinguishable within the gymnosperms because they have vessel elements, a system of channels mostly found in the angiosperms, which transport water within the plant. Covering 70 species over three genera, the gnetophyta are morphologicallyvariable, including trees, shrubs, stumps, vines and creepers with leaf shapes ranging from opposite, to whorled, scale-like and straplike. The distribution is determined by the genus: Welwitschia are unique to the Namib Desert and surro...
Gymnosperms reproduce with an alteration of generations, meaning their reproductive cycle has both haploid and diploidphases. As in all other vascular plants, gymnosperms have a sporophyte dominant life cycle (the sporophyte is the diploid multicellular stage, which comprises the body of the plant, i.e., a leafy tree). The gametophytephase is relat...
Angiosperm– The term for the group of flowering plants which reproduce via seeds contained within ovules.Vascular Plants– A large group of plants defined as those which have tissues (xylem and phloem) for conducting minerals and water throughout the plant.Non-vascular Plants– The group of plants without the xylem and phloem vascular tissues, although they usually transport water through other mechanisms.1. For a plant species to be ‘dioecious’, it must: A. Reproduce asexually B. Have both male and female organs C. Have separate male and female individuals D.Not reproduce 2. Which division of the gymnosperms is most commonly used to create paper? A. Conifers B. Cycads C. Gnetophyta D.Gingkophyta 3. What role does the cone have in the gymnosperm lif...
Although the taxonomic division Spermatophyta is no longer accepted, the term spermatophyte is used to refer collectively to the angiosperms (flowering plants) and gymnosperms (conifers, cycads, and allies).
- The Editors of Encyclopaedia Britannica
Identify the structures involved in reproduction of gymnosperms. As with angiosperms, the lifecycle of a gymnosperm is also characterized by alternation of generations. In conifers such as pines, the green leafy part of the plant is the sporophyte, and the cones contain the male and female gametophytes (Figure 1).
In contrast, all seed plants, or spermatophytes, are heterosporous, forming two types of spores: megaspores (female) and microspores (male). Megaspores develop into female gametophytes that produce eggs, and microspores mature into male gametophytes that generate sperm.
Oct 14, 2024 · In gymnosperms, when the nuclei of the two sperm meet the egg cell, one nucleus dies and the other unites with the egg nucleus to form a diploid zygote. The fertilized egg undergoes mitosis to begin the development of a new sporophyte generation—the multicellular embryo of the seed .
Sep 22, 2021 · Gymnosperms are heterosporous seed plants that produce naked seeds. They appeared in the Carboniferous period (359–299 million years ago) and were the dominant plant life during the Mesozoic era (251–65.5 million years ago).
