Question

The biological species concept classifies a species based on a morphological characteristics. b reproductive isolation. c the niche the organism occupies in the environment. d genetic relationships between an organism and its ancestors. e both a and b.

Short answer

The correct answer is b, reproductive isolation.

Step-by-step solution

Understanding the Biological Species Concept

The biological species concept is a way of classifying species (group of living organisms) based on certain criteria. This concept was developed by a scientist named Ernst Mayr.

Analyzing the Choices

Now let's look at the choices. Morphological characteristics are about the form and structure of organisms, which can be misleading as different species can have similar appearances. The niche the organism occupies in the environment and genetic relationships to ancestors are more relevant to ecological or phylogenetic species concepts, not the biological species concept. Both a and b option would mean that the biological species concept uses both reproductive isolation and morphological characteristics, which is not accurate.

Choosing the Right Option

The biological species concept, as proposed by Ernst Mayr, defines a species as groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups. So, the correct answer is based on 'reproductive isolation'.

Key concepts

Reproductive Isolation

In the realm of biological classification, reproductive isolation plays a pivotal role. It's the cornerstone of the Biological Species Concept (BSC), which posits that a 'species' comprises individuals that can mate with one another and produce fertile offspring, but cannot do so with members of other species. This reproductive barrier ensures the genetic distinctiveness of a species.

There are two types of reproductive isolation: prezygotic, which occurs before fertilization (e.g., differences in mating seasons or behaviors) and postzygotic, which happens after fertilization (e.g., resulting offspring are sterile). These mechanisms prevent the gene pools of different species from mixing, which is crucial for maintaining species boundaries over time.

Ernst Mayr

The Biological Species Concept was substantially shaped by Ernst Mayr, an influential evolutionary biologist. His elucidation of species as groups of interbreeding populations isolated from others was a significant leap in species classification. Mayr's perspective emphasized the importance of reproductive isolation in maintaining species identity.

Mayr's contributions went beyond species concepts, encompassing the realms of systematics, biogeography, and the philosophy of biology. His work was central to the modern synthesis, which is a fusion of Mendelian genetics with Darwinian evolution, providing a comprehensive framework for biological diversity.

Species Classification

The task of species classification is a complex and contentious one, with multiple concepts guiding scientists. While the Biological Species Concept, associated with Ernst Mayr focuses on reproductive isolation, other concepts such as the Phylogenetic Species Concept (PSC) and Morphological Species Concept (MSC) prioritize genetic history and physical form, respectively.

Each species concept has its applications and limitations, and the choice can depend on the context in which the classification is performed. For example, the BSC is often employed in studies concerning sexual reproduction and gene flow, while MSC might be preferred when working with fossils where breeding behaviors cannot be observed.

Morphological Characteristics

Though not the primary focus of the Biological Species Concept, morphological characteristics are still essential in the taxonomic toolkit. These are the physical traits and structures of organisms, which can be observed and measured. Morphology often provides the first clues in identifying and categorizing species.

Morphological traits can, however, be misleading due to convergent evolution where unrelated species evolve similar traits. This can cause confusion in distinguishing species based solely on physical appearance. Therefore, while useful, morphological characteristics are usually considered alongside other attributes like genetics and reproductive capabilities when classifying species.