Plant Kingdom – Introduction

Correct Answer: A

In 1969, R.H. Whittaker proposed the Five Kingdom classification system. According to this system, all living organisms are divided into five kingdoms: Monera, Protista, Fungi, Plantae and Animalia. This classification was based on important criteria such as cell structure, body organisation, mode of nutrition, reproduction and evolutionary relationships.

Correct Answer: A

In earlier classification systems, organisms such as fungi and some members of Monera and Protista were grouped under Kingdom Plantae because they possessed cell walls. However, modern classification separates them into different kingdoms based on differences in cell structure, nutrition and other characteristics. Fungi are now placed in Kingdom Fungi, while prokaryotic organisms are placed in Monera and unicellular eukaryotes in Protista.

Correct Answer: B

Cyanobacteria were earlier called blue-green algae because they perform photosynthesis like algae. However, they are actually prokaryotic organisms lacking a true nucleus and membrane-bound organelles. Therefore, in modern classification systems they are placed in Kingdom Monera instead of being considered true algae.

Correct Answer: A

In the study of Kingdom Plantae, plants are broadly classified into five major groups based on their structure and reproductive features. These groups are Algae, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms. They represent increasing levels of complexity from simple thalloid plants to highly developed flowering plants.

Correct Answer: A

The earliest classification systems grouped plants based on gross external morphological characters such as habit, colour, number and shape of leaves. These characters were easy to observe but did not always show true relationships among plants.

Correct Answer: B

Linnaeus proposed an artificial system of classification that was mainly based on the structure of the androecium, particularly the number and arrangement of stamens in flowers.

Correct Answer: B

Artificial classification systems use only a few easily observable characters to classify organisms. Because of this, they often separate closely related species and do not reflect true evolutionary relationships.

Correct Answer: C

Vegetative characters such as leaf shape and plant habit can vary depending on environmental conditions. Therefore, they are considered less reliable compared to reproductive characters when classifying plants.

Correct Answer: C

Natural classification systems group organisms based on natural relationships by considering multiple characteristics such as external morphology, anatomy, embryology, ultrastructure and phytochemistry.

Correct Answer: C

George Bentham and Joseph Dalton Hooker proposed a natural system of classification for flowering plants. Their system was based on natural affinities among plants and used many characters such as morphology and internal structures.

Correct Answer: B

Modern classification systems are based on phylogeny, which means evolutionary relationships among organisms. Scientists study how different organisms evolved from common ancestors. By analysing morphological, anatomical, molecular and genetic evidence, organisms are grouped according to their evolutionary history. Therefore, phylogenetic classification is widely accepted today.

Correct Answer: B

Phylogenetic classification is based on evolutionary relationships among organisms. It assumes that organisms placed in the same taxonomic group (taxa) share a common ancestor. This means they evolved from a similar ancestral form and therefore show similarities in genetic, structural and evolutionary features.

Correct Answer: B

Modern classification systems use information from many sources such as morphology, anatomy, embryology, cytology, biochemistry and molecular biology. These sources help scientists understand evolutionary relationships among organisms, especially when fossil evidence is not available.

Correct Answer: C

Numerical taxonomy is a modern method of classification that uses computers to analyse many observable characteristics of organisms. In this method, numbers and codes are assigned to different characters and the data are processed statistically. Each character is given equal importance and hundreds of characters can be analysed at the same time. This helps scientists classify organisms more objectively and accurately.

Correct Answer: B

Cytotaxonomy is the branch of taxonomy that uses cytological information such as chromosome number, structure and behaviour to classify organisms and understand their relationships.

Correct Answer: A

Chemotaxonomy is the classification of plants based on their chemical constituents such as alkaloids, flavonoids and other biochemical compounds. These chemicals help in identifying relationships between organisms.