The definition of species: A fundamental pillar in biology

The definition of “species” is one of the most fundamental concepts, and at the same time one of the most debated. Understanding what a species is is essential for the classification and study of living organisms, as well as for the conservation of biodiversity.

What is a Species?

Classic Definition: Biological Concept of Species

The most widely accepted definition is the biological concept of speciesproposed by biologist Ernst Mayr in 1942. According to this concept, a species is a group of individuals that can interbreed and produce fertile offspring, while being reproductively isolated from other groups.

Other Definitions of Species

1. Morphological Concept of Species

The morphological concept defines a species based on differences in the shape and structure (morphology) of organisms. This definition is based on the observation of distinctive physical characteristics.

2. Phylogenetic Concept of Species

The phylogenetic concept considers a species as the smallest group of individuals that share a common ancestor and can be differentiated from other groups by unique diagnostic characteristics.

3. Ecological Concept of Species

According to the ecological concept, a species is a set of organisms adapted to a particular ecological niche. This definition focuses on the adaptations and ecological roles of organisms.

Limitations

1. Hybrids and Gene Flow

The biological concept of species faces challenges with the existence of hybrids, individuals resulting from the crossing of two different species, which can be fertile in some cases. Examples include the liger (a cross between a lion and a tiger) and the grizzly-polar bear.

2. Cryptic Species

Cryptic species are those that are morphologically indistinguishable but genetically distinct. These species present a challenge to the morphological species concept.

3. Microorganisms and Asexual Reproduction

For organisms that reproduce asexually, such as many bacteria, definitions based on crossing over and fertile offspring are not applicable, complicating classification.

Importance of Defining a Species

1. Biodiversity Conservation

Accurate species identification is crucial for conservation. Knowing what species exist and where they live enables the implementation of effective conservation strategies.

2. Evolutionary Studies

The definition of species is fundamental to evolutionary studies. Understanding how species differentiate and adapt to their environments helps to unravel evolutionary processes.

3. Medicine and Agriculture

In medicine and agriculture, correctly identifying the species of pathogens, pests and beneficial organisms is vital for the development of treatments, resistant crops and biological control methods.

Relevant Examples in Biology

1. Speciation in Darwin’s Finches

Darwin’s finches, studied in the Galapagos Islands, are a classic example of adaptive speciation. Through adaptation to different ecological niches, these finches have evolved into several distinct species, each with unique characteristics.

2. Speciation in Frogs of the Genus Rana

Studies on frogs of the genus Frog In Europe they have shown that what was previously considered a single species is actually a complex of cryptic species, each adapted to specific microhabitats.

In summary, although the definition of species can be complex and sometimes controversial, its importance in biology is undeniable. Continuing to explore and refine this concept is crucial to advancing our knowledge of life and our efforts to preserve global biodiversity.