CLASSIFICATION OF ORGANISM IN PALEONTONLOGY

Introduction :

Organism classification is the process of organizing and grouping organisms into different categories based on their characteristics, evolutionary relationships and genetic similarities. It focuses on understanding relationships among organisms and offers a structured approach to studying and interpreting life’s diversity on Earth. There are three types of classification are as follows : 

1. TAXONOMY
2. PHYLOGENY
3. PHENETIC OR TYPOMORPHIC

A. TAXONOMIC CLASSIFICATION:

A taxonomy (or taxonomical classification) is a scheme of classification based on their morphological similarities or dissimilarities. In which organism are organized into groups or rank. These ranks, broad to specific, including kingdom, phylum, class, order, family, genus, and species.

1. Kingdom: The highest taxonomic rank, organisms are divided into distinct kingdoms based on their fundamental characteristics (Species)and organization. Examples include: Animalia (animals), Plantae (plants), Fungi (fungi), Protista (protists), or Monera (bacteria).
2. Phylum: Within each kingdom, organisms are further divided into different phyla based on their overall body plan and structural characteristics. For example, in the animal kingdom, phyla include Chordata (chordates), Arthropoda (arthropods), and Mollusca (mollusks).
3. Class: Phyla are further divided into classes depend on more specific features and characteristics. For example, within the phylum Chordata, the classes include Mammalia (mammals), Reptilia (reptiles), and Aves (birds).
4. Order: Classes are subdivided into orders, which represent distinct groups of organisms with shared characteristics. Examples of orders include Carnivora (carnivores), Primates (primates), and Rodentia (rodents).
5. Family: Orders are further divided into families, which are smaller groups of organisms that share more specific characteristics. Families often end in the suffix "-idae." For example, within the order Primates, families include Hominidae (great apes and humans) and Cercopithecidae (Old World monkeys).
6. Genus: Families are divided into genera (singular: genus), which represent even more closely related groups of organisms. Genera are usually given a Latin or Greek name and are capitalized.  For example, within the family Hominidae, the genus Homo includes modern humans and their extinct relatives.
7. Species: The most specific level of classification or fundamental unit of taxonomic classification. A species is a group of individuals that share similar characteristics and composed of two parts: the genus name (capitalized) and the species name (lowercase). For example Homo sapiens is the scientific name for modern humans.

B. PHYLOGENIC CLASSIFICATION :

Phylogenetic classification, also known as cladistic classification or phylogenetics, it is the groups of organisms that based on their evolutionary relationships.

The foundation of phylogenetic classification is the construction of phylogenetic trees or cladograms, which are “graphical representations” of the branching patterns of evolutionary relationships among organisms. These cladogram depict the sequence of branching events, showing the common ancestors and the divergence of lineages over time.

Phylogenetic classification is based on common ancestry. Organisms that share a recent common ancestor are grouped together, showing how life has evolved through gradual changes over time.

`Phylogenetic classification groups organisms into clades, which are monophyletic groups that include a common ancestor and all its descendants.

 For example,

A

/   \

B     C

/ \   / \

D   E F   G

 

In this example, we have four organisms labeled A, B, C and D, represented as branches in the cladogram. The cladogram illustrates their evolutionary relationships based on shared derived characteristics.

• Organisms A, B, and C share a common ancestor, represented by the base of the cladogram.
• Organism A diverged first and is the most ancestral.
• Organisms B and C diverged from A and form a more recent common ancestor.
• Organisms D, E, F and G are descendants of organism A ,the common ancestor of B and C.
• Organisms D and E are more closely related to each other than to F and G.

This cladogram displays evolutionary connections through a branching structure

C. PHENETIC OR TYPOMORPHIC :

Phenetic or typomorphic classification is a method of classification based on the overall similarity of organisms, focusing on observable traits and characteristics rather than evolutionary relationships. It groups organisms together based on common similarities in their physical features without considering their evolutionary history.

This classification also known as morphological classification. It focuses on identifying and categorizing organisms based on distinct and defining morphological characteristics.

Example :

• Lophophore of brachiopoda
• Dentition pattern of bivalve

Note :Taxonomic classification organizes living organisms into standardized ranks for study.

Conclusion :

Phylogenetic classification gives a structured and objective way to understand how organisms are evolutionarily related. It is based on species have evolved and diverged from common ancestry. While taxonomy and phenetics focus on categorizing organisms by observable traits.

It's important that phenetic or typomorphic classification is often less precise in reflecting true evolutionary relationships compared to phylogenetic classification, which considers genetic and evolutionary data. Phenetic classification is mainly used for practical purposes, such as field identification or initial categorization based on readily observable features.