Classification of plant kingdom biology discussion
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Answer:
Biologist Whittaker gave us the Five Kingdom Classification, classifying all the living organisms into five kingdoms – Protista, Monera, Fungi, Plantae, and Animalia. To know more about plants, it is essential to know more about the Kingdom Plantae or in simple words the plant kingdom.
When you enter this kingdom, all you will find is plants and plants and more plants. You will be amazed to see the different kinds of plants that are included here. You can see microscopic plants like the algae as well as the tallest trees like the Sequoia.
Some plants have the most beautiful and attractive looking structures called flowers, while some don’t have any. In some plants, you can see a proper root system, shoot system, and leaves, while in the simpler plants, it is just a thalloid structure. So, how did the early biologists classify plants?
Classification within Kingdom Plantae
Very early on, biologists used the superficial features of plants and classified them based on these features. Some of the morphological features included colour, number, the shape of leaves as well as the habitat, etc.
This system was considered as an artificial system of classification, as plants were classified based on vegetative characters. These vegetative characters can always show changes because of the effect of the environment. Therefore, many closely related species were classified under different divisions.
As biologists became more aware of the other characteristics of plants, they slowly began another system of classification, called the natural system of classification. This system considered the external and internal features of plants while classifying them.
However, currently, the phylogenetic classification is being followed. This is based on evolutionary relationships between various organisms. This is more advanced. It is assumed that all organisms that are classified under one heading will have the same common ancestor. Thus many difficulties in classification have been overcome, by following this system.
And so, as organisms evolved various classification systems have come into being. The current system of classification that is being followed is widely accepted. According to this, the Kingdom Plantae has been divided into five major groups. They are:
- Thallophyta
- Bryophyta
- Pteridophyta
- Gymnosperms
- Angiosperms
Each group of plants has special and unique features that belong exclusively to that group. While the thallophytes are the simplest of the plants, the angiosperms are plants with a complex structure and a very well developed vascular system and reproductive system.
The gymnosperms are the group of plants that have an evolutionary significance. These are the first plants to have developed seeds, which is an efficient mechanism of continuing the plant generation at places away from the parent plant.