Plant Diversity and Morphology Introduction

Study Notes

The course PEBO 102 focuses on the study of diversity in plant forms (mosses, ferns, cone-bearing plants, flowering plants, fungi, and algae).
Diversity in plant life can be understood from various aspects: classification, habitat, habit or life form, size, life cycle, nutrition, and economic importance.

Taxonomy is the scientific discipline that deals with the classification of living things.
There are at least 5 million different kinds of organisms in the biosphere, necessitating the classification of living things into groups with similar characteristics.
Carolus Linnaeus introduced a simpler system of classification in the 18th century, using a binomial system consisting of two words: the generic name and the specific epithet.
The scientific name of every species is a binomial, with the generic name always preceding the specific epithet.

A classification that depicts genetic relationships is said to be a natural or phylogenetic classification.
Plants are classified into divisions based on differences in photosynthetic pigments, manner of leaf development, structure of the conducting or vascular tissues, and modes of reproduction.
The most fundamental distinction in living organisms is that between prokaryotes and eukaryotes.

Prokaryotes do not have true nuclei, lack membrane-bound cellular organelles, and have a single circular molecule of DNA.
Genetic material is not associated with proteins, and reproduction is predominantly by cell division.
Prokaryotes are mainly absorptive, photosynthetic, or chemosynthetic, and exhibit solitary unicellular or colonial unicellular organization.
The cell walls of most prokaryotes contain muramic acid, distinguishing them from other organisms.
Prokaryotes are recognized as a separate kingdom, the Kingdom Monera, which comprises all bacteria, including cyanobacteria (blue-green algae).

Eukaryotes have a definite nucleus bounded by a double membrane, complex chromosomes, and DNA associated with proteins.
Eukaryotes possess complex cellular organelles, such as mitochondria, and vacuoles bounded by a single membrane or tonoplast.
Many eukaryotes exhibit integrated multicellularity and sexual reproduction, which are absent in prokaryotes.
Plant eukaryotes have protoplasts connected by plasmodesmata, whereas in animals, protoplasts are in more direct contact due to the absence of cell walls.

Plants are generally multicellular, photosynthetic organisms found in water and on land.
However, few plants are single-celled or unicellular.
The concept of uni- and multicellularity is important in understanding the diversity of plant life.

Taxonomy is the scientific discipline that deals with the classification of living things
There are at least 5 million different kinds of organisms in the biosphere, necessitating classification into groups with similar characteristics
The practice of referring to organisms by Latin names began in the Middle Ages (between the 5th and 15th centuries)
Initially, organisms were grouped into genera (singular: genus) and were then identified by descriptive Latin phrase names, known as polynomials

The binomial system of classification was introduced by Carolus Linnaeus in the 18th century
The scientific name of every species consists of two words: the generic name and the specific epithet
The generic name is always capitalized, and the specific epithet is not
The specific epithet is descriptive and is usually written in lowercase letters
The scientific name is always printed in italics or underlined when written or typed

A classification that depicts genetic relationships is said to be a natural or phylogenetic classification
Plants are classified into divisions based on features such as photosynthetic pigments, leaf development, vascular tissues, and modes of reproduction
Early taxonomists classified living things as either plant or animal, but this classification was later revised to include fungi and bacteria

Prokaryotes do not have true nuclei, lack membrane-bound cellular organelles, and have a single circular molecule of DNA
Prokaryotes reproduce predominantly by cell division, and their mode of nutrition is mainly by absorption
Prokaryotes are recognized as a separate kingdom – the Kingdom Monera, which comprises all bacteria, including cyanobacteria
Eukaryotes have a definite nucleus bounded by a double membrane, complex chromosomes, and complex cellular organelles such as mitochondria
Eukaryotes also exhibit integrated multicellularity and sexual reproduction, which are absent in prokaryotes

Unicellular organisms are single-celled, while multicellular organisms are composed of multiple cells
Plants are generally multicellular photosynthetic organisms, but few are single-celled or unicellular
In plant eukaryotes, the protoplasts of contiguous cells are connected by plasmodesmata, allowing for integration and communication between cells