In this lesson, we will explore gymnosperms, which are a unique group of plants that do not have bright flowers or seeds that are protected in fruit.
We will examine types of them as well as their characteristics and the way they reproduce.
Definition of Gymnosperms
One crucial step in the evolutionary history of all plants was the development of seeds. Seeds provide a viable means for dispersal of offspring without the need for water.
They’re a far more efficient way of dispersal and allow plants to exist away from direct sources of water.Gymnosperms were the first plants to have seeds. They are often referred to as having naked seeds because they do not have flowers, and their seeds develop on the surface of the reproductive structures of the plants rather than being contained in a specialized ovary. These seeds are often found on the surfaces of cones and short stalks.
Characteristics of Gymnosperms
Gymnosperms are a group of plants with the following unique characteristics:
- They do not have an outer covering or shell around their seeds
- They do not produce flowers
- They do not produce fruits
- They are pollinated by the wind
Types of Gymnosperms
All gymnosperms are found in four major divisions of plants. The divisions are Ginkgophyta, Cycadophyta, Gnetophyta, and Coniferophyta.The division Ginkgophyta contains the Ginkgo Biloba or Maidenhair tree. These trees were originally only found in China but have now been propagated all around the world.
They grow to be approximately 20-35 meters high and are easily recognized by their fan-shaped leaves. The trees are either male or female. Ginkgo trees do not produce cones.
Their seeds begin as two ovules that grow on the end of a stalk. Once the ovules are fertilized by pollen carried in the wind, they grow into a light yellow-brown seed that falls to the ground and are known for their awful smell, which is often said to resemble dog feces or vomit.The division Cycadophyta contains the plants commonly known as cycads. The cycads thrived during the Jurassic period, but only a few species live today. These plants are characterized by a large crown of leaves and a stout, thick trunk. They are found in most tropical or sub-tropical parts of the world and are commonly confused with ferns or palms. Their seeds grow on short stalks called strobili at the center of the plant and are pollinated by the wind.
The division Gnetophyta contains approximately 70 species of woody plants. Two well-known species of the division are Welwitschia and Ephedra. The Welwitschias is a unique plant found in the deserts of Namibia and Angola.
It is characterized by its two long leaves that grow from their roots throughout the duration of their life. They produce seeds in small cones. The Ephedra have long slender branches with tiny, scale-like leaves. Seeds are produced at the ends of their branches. Materials obtained from the Ephedra plant are commonly used as a stimulant and are a controlled substance in many places.
The division Coniferophyta is made up mostly of evergreen trees and shrubs. They are found on all continents except for Antarctica. You are probably familiar with pine trees, which are very common examples of conifers.
They have needles or scale-like leaves and bear seeds in cones.
As you can see, gymnosperms are a unique group of plants. They do not have bright flowers to show off or sweet delicious fruits enclosing their seeds. Instead, they have naked seeds that are found in cones or on short stems.
They are the most primitive of seeds plants and can live in a variety of environments. Chances are you are not far from a gymnosperm right now!
Ensure that you can achieve these goals after watching this lesson on gymnosperms:
- Understand the nature of gymnosperms
- Point out their main characteristics
- Name the four major divisions of gymnosperms and provide examples of each