Compare and contrast the morphospecies concept, the biological species concept, and the phylogenetic species concept. What criterion does each use to identify species? What are the pros and cons of each?
The correct answer and explanation is :
The morphospecies concept, biological species concept (BSC), and phylogenetic species concept (PSC) each use different criteria to define species.
- Morphospecies Concept: This concept identifies species based on distinct morphological (physical) characteristics.
- Criterion: Differences in size, shape, color, or other anatomical traits.
- Pros:
- Useful for classifying fossils and extinct species.
- Can be applied to organisms that reproduce asexually.
- Cons:
- Subjective, as different taxonomists may classify species differently.
- Does not account for genetic or reproductive differences.
- Biological Species Concept (BSC): This defines species based on reproductive isolation—organisms that can interbreed and produce fertile offspring are considered the same species.
- Criterion: Ability to reproduce and produce viable offspring.
- Pros:
- Emphasizes genetic isolation, which aligns with evolutionary theory.
- Works well for many sexually reproducing organisms.
- Cons:
- Not applicable to asexual organisms or extinct species.
- Difficult to test in species that do not naturally overlap.
- Phylogenetic Species Concept (PSC): This defines species based on evolutionary history and shared ancestry, using genetic and morphological data to identify the smallest distinct groups.
- Criterion: Shared evolutionary history and unique genetic markers.
- Pros:
- Can be applied to all organisms, including fossils and asexual species.
- Uses objective genetic data for classification.
- Cons:
- May lead to over-splitting of species.
- Requires extensive genetic analysis, which is time-consuming and expensive.
Each concept has strengths and weaknesses, and taxonomists often use multiple approaches to classify species accurately.