Do all plants grow from seeds?
No, there are actually a few plants that do not make seeds. Whether or not a plant makes seeds is one criteria used to classify plants. How else could you distinguish between plants?
Plants are formally divided into 12 phyla (plural for phylum), and these phyla are gathered into four groups (Figure below). These four groups are based on the evolutionary history of significant features in plants:
- Nonvascular plants evolved first. They are distinct from the algae because they keep the embryo inside of the reproductive structure after fertilization. These plants do not have vascular tissue to transport nutrients, water, and food.
- Seedless vascular plants evolved to have vascular tissue after the nonvascular plants but do not have seeds.
- Gymnosperms evolved to have seeds but do not have flowers.
- Flowering plants, or angiosperms, evolved to have vascular tissue, seeds, and flowers.
The plant kingdom contains a diversity of organisms.
- angiosperm: Flowering plant with vascular tissue, seeds, and flowers.
- gymnosperm: Plant with vascular tissue and seeds but no flowers.
- nonvascular plant: Plant without vascular tissue.
- seedless vascular plant: Plant with vascular tissue but no seeds or flowers.
- Nonvascular plants were the first plants to evolve and do not have vascular tissue.
- Seedless vascular plants have vascular tissue but do not have seeds.
- Gymnosperms have seeds but do not have flowers.
- Angiosperms have vascular tissue, seeds, and flowers.
Use the resource below to answer the questions that follow.
- Plant Body Systems and Classification Part 1 at http://www.youtube.com/watch?v=6FnPVFPSt3A (7:21)
- What plant group/groups are included in non-vascular plants
- What group/groups of plants have seeds?
- What group/groups of plants have fruit?
- Where do you usually find non-vascular plants? Why?
- From what group of plants do we get "softwood"?
- What distinguishes the gymnosperms from other plants?
- List the following major features of plants in the order they evolved: seeds, vascular tissue, flowers.