Concept of Species: Static, Dynamic, Typological, Genetical & Biological Concepts

Botany Sir Himansu

CONCEPT OF SPECIES

1. Static Concept

Proposed by C. Linnaeus

According to this concept, species are fixed and immutable (not changeable).

2. Dynamic Concept

Given by Lamarck

According to this concept, species is dynamic and mutable.

3. Typological Concept

Given by Aristotle and Plato

According to this concept, each species has a characteristic pattern of body organisation.

4. Genetical Concept

Given by Lotsy

According to this concept, all individuals belonging to the same species are genetically similar, hence have the same number of chromosomes and descend from a common ancestor.

5. Biological Concept

Given by Ernst Mayr (Darwin of the 20th century)

It is the widely accepted concept of species.

According to this concept, species are groups of morphologically similar individuals which can freely interbreed in nature and produce fertile offspring, but are reproductively isolated from other species.

Basis of biological concept: Reproductive isolation

It is the widely accepted concept of species.

Objection

This theory is not applicable to such individuals which do not reproduce sexually.

Example: Kingdom Monera

Exceptions

  1. Mule — ♂ Donkey × ♀ Horse → sterile
  2. Hinny — ♂ Horse × ♀ Donkey → sterile
  3. Lion × Tiger → Liger — ♂ Lion × ♀ Tiger
  4. Tiger × Lion → Tigon — ♂ Tiger × ♀ Lion

Criteria of species for asexually reproducing organisms

For such organisms, species are recognised by their physical and biochemical characters.