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PLANT KINGDOM
BASICS OF CLASSIFICATION THALOPHYTS AND BRAYOPHYTES AND PTERIDOPHYTES
Introduction
Our understanding of the plant kingdom has changed over time. first Thalophytes are come which have no root, stem, leaves. it live in water and also dead in water. it did not move anywhere.
thalophyta figure
Next is Brayophytes it also not have root, stem and leaves but it live both of the places water and land[specific land like moisture ].
bryophyta figure
Other is Pteridophyta it have normal root , stem and leaves. it is the first plant kingdom which have vascular bundle [xylem and Phloem are collectivly known as vascular bundle ].
pteridophyta figure
work of vascular bundle
xylem tranport water in plant and Phloem transport food in plants.
xylem phloem figure
The kingdom -Plantae now includes gymnosperm and angiosperm.
TYPES OF CLASSIFICATION SYSTEM
These include artificial system, natural system and phylogenetic system of classification.
The various systems used in classification of plants are being discussed here.
1. ARTIFICIAL SYSTEM OF CLASSIFICATION
This system is based on comparison of one or a few gross superficial morphological characteristics, which are helpful in easy identification of organism. This system remained in use for about two thousand years.
ADVANTAGES
Advantages of Artificial system are given below :-
(1). Artificial system is easy to remember as only one or few character are used.
(2). The traits used are of intrested to human.
DISADVANTAGES
Disadvantages of Artificial system are given below :-
(1). These system is uses only few superficial characters (i,e habits, number , colours and shapes of leaves )which may be very common in many organism grouped together.
(2). They considered mainly the vegetative characters or the androcium characters as given by linneaus .
(3). It does not demonstrate natural and phylogenetic relationship.
NATURAL SYSTEM OF CLASSIFICATION
It is also as phenetic system of classification. The natural system of classification is based on natural affinites among the organisms. It considers both external and internal features like structure, anatomy, embryology and phytochemistry.
ADVANTAGES
Advantages of Natural system of classification is give below :-
(1). only related organisms are kept in a group.
(2). Unrelated organisms are kept in seperate groups.
(3). It shows possible origin of different taxa.
DISADVANTAGES
Disadvantages of natural sytstem classification is given below :-
(1). There is more emphasis given on natural character.
(2). In this system , related families are seperated and unrelated families are put togther.
(3). Evolutionary basis of organ's as organisms are neglected.
PHYLOGENETIC SYSTEM OF CLASSIFICATION
The phylogenetic system of classification indicates the evolutionary as well as genetic relationship among organisms. This system is based on fossils record of biochemical , anatomical , morphological, physiological, embryological and genetical studies.
The system was intiated by Engler and Prantl (1887-1889) in Die Naturalichen pflanzefamilen
In phylogenetic system , flowering plants are placed inascending series related t complexity of floral morphology.
ADVANTAGES
(1). Families and orderin this system are of small size.
(2). This system is in conformation with the modern view of phylology .
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