Final answer:
Gymnosperms are divided into four phyla: Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta. These range from towering conifer trees to the single living species of Ginkgophyta, the Gingko biloba. The life cycle typically includes the development of male and female cones, pollen transfer by wind, and seed production.
Step-by-step explanation:
Diversity of Gymnosperms
Gymnosperms, which include plants with seeds that do not produce fruits and typically bear seeds in cones, are classified into four major phyla. These phyla are:
- Coniferophyta - This is the most diverse and widely recognized phylum. It includes trees such as pines, firs, spruces, cedars, and the coastal redwoods, known for being some of the tallest living vascular plants.
- Cycadophyta - Cycads resemble palm trees and are mostly found in tropical climates. They have stout and woody trunks with a crown of large, hard, and stiff leaves.
- Ginkgophyta - This phylum consists of only one living species, Gingko biloba, which is often planted as an ornamental tree.
- Gnetophyta - A diverse group, gnetophytes include three unusual genera: Gnetum, Welwitschia, and Ephedra. They share some characteristics with angiosperms, such as the presence of vessel elements in their wood.
Life Cycle of a Typical Gymnosperm
A typical gymnosperm life cycle includes the development of male and female cones, where male cones release pollen that is carried by wind to female cones. The fertilized female cone then develops seeds on its scales, which upon maturity, are dispersed into the environment to grow into new plants. This cycle, with its adaptations for reproduction without water, is a hallmark of gymnosperms ranging from small shrubs to towering trees.