Systematics Angiosperm Notes 5th Sem BSc Botany 2023.8 Semesters / 4 Years Degree Program. Study Plan BS Hons in Botany. Faisalabad’s GC University. 5. V.N. Naik 2005 Taxonomy of Angiosperms. 20. Botany. B.Sc. Year two. Only five of the nine questions in Paper I, Diversity of Angiosperms: Systematics, must be answered by the candidate. BSc Botany Fifth Semester Systematics Angiosperm Notes 2023.
Systematics of angiosperms
The rules regulating the classification of plants are the subject of taxonomy. The Greek words for arrangement and laws, taxis and nomos, are combined to form the word taxonomy. Phylogenetic links between various plant groups are another goal of classification.
Some of the characteristics of angiosperms include:
- All angiosperms have flowers at some stage in their life.
- Angiosperms have small pollen grains that spread genetic information from flower to flower.
- All angiosperms have stamens.
What are some examples of angiosperms and describe their characteristics?
The most prevalent angiosperms are fruit trees. Before turning into fruits like apples, oranges, and cherries, a variety of blooms can be seen on the branches of fruit trees. Different types of insects and mammals pollinate these plants.
Angiosperm Life Cycle
The main stage of an angiosperm’s life cycle is known as the adult, or sporophyte, phase. Angiosperms are heterosporous, just like gymnosperms. Therefore, they make microspores, which will produce pollen grains as the male gametophytes, and megaspores, which will form an ovule that includes female gametophytes.
TAXONOMY OF ANGIOSPERMS
Taxonomy is concerned with the laws controlling the classification of plants. The term taxonomy comprises two Greek terms taxis – arrangement and nomos- rules. Otherwise known as systematic botany, plant taxonomy. Classification, identification, description, and naming of plants are the bases of plant taxonomy. The form and structure of plants serve as the basis for taxonomic knowledge about them. The knowledge gathered through taxonomy is useful in the sectors of medicine, agriculture, forestry, etc.
The ultimate goal of classification is to systematically sequence plants according to their similarities. Plants that are closely related are kept together, while those that are unrelated are kept apart in separate groups.
Three systems—artificial, natural, and phylogenetic—can be used to generally describe the various classification schemes put forth by earlier taxonomists.
It was based on just a single superficial character, possibly a few. In 1753, Carolus Linnaeus of Sweden published his book ‘ Species Plantarum’ wherein he described 7,300 species. Based on the number, union, length, and a few other characteristics of the stamens, he classified the plants into 24 classes. As a result, this system of classification is also sexual. It held a significant position in comparison to other classification schemes at the time. More than other characteristics, flowery ones were regarded to be significant.
Phylogenetic links between various plant groups are another goal of classification. The closely related plants exhibit more similarities than differences.
The first classification schemes were straightforward and based on just one or a few features. They attributed importance to vegetative qualities. Because floral characters are more enduring and stable, later classification systems placed more emphasis on them.
Plants are categorized in this system according to their natural affinities. In this system, more characters are taken into account. It is mostly based on all the data that were accessible at the time of direct plant observation. Two British botanists, George Bentham and Sir Joseph Dalton Hooker proposed what is considered to be the most significant natural method of classifying seed plants. It helps to determine the links between diverse groups of plants. It does not, however, make an effort to reveal the evolutionary connections between various plant families.
This method is based on the genetic links and evolutionary history of several plant families. In addition to this, it employs as many taxonomic characters as possible. The idea behind Charles Darwin’s Origin of Species served as sufficient inspiration for the development of the phylogenetic system of classification. Adolf Engler (1844-1930) and Karl Prantl (1849-1893) of Germany presented a phylogenetic scheme in their work on ‘Die Naturlichen Pflanzen Familien’. When compared to bisexual flowers pollinated by insects with a perianth with two whorls, this system regarded floral characteristics like a single whorl of perianth or no perianth and unisexual flowers pollinated by the wind as primitive characters.