Bio354 F23 Unit3_Lecture1_What is a Species(slides) 2

What is a Species?

All materials copyright Bio 354 ©2023. Duplication or posting of any kind is strictly prohibited.

Learning Objectives

  • Describe some of the species concepts and what they have in common
  • Identify strengths and weaknesses of biological species concept
  • Describe how speciation happens
  • List features used to recognize the existence of a separate species

Introduction to Species

The concept of a species is complex and includes various interpretations among scientists. Definitions are essential for studying biodiversity and evolutionary processes.

Continuous Nature of Evolution

  • Evolution is a continuous process; thus, some generations of organisms will overlap.
  • Speciation is defined as the formation of new species through evolutionary processes.

Different Perspectives on Species

Common Inquiry
  • Are the organisms presented in the visual examples different species or the same species?
Visual Differentiation
  • The presentation suggests assessing species by visual characteristics; however, morphological traits can sometimes be misleading.

Comparisons Among Species

Owl Classification Example
  • Question posed: Which two owls are most closely related?
    • Options:
      A. 1 and 2
      B. 1 and 3
      C. 2 and 3
  • Owl Identifications:
    1. Eastern Screech Owl (Megascops asio)
    2. Western Screech Owl (Megascops kennicottii)

Definition and Challenge of Species

Consensus Issues
  • Scientists cannot universally agree on a definitive species definition.
Biological Species Concept
  • Defined as a group of interbreeding populations which are reproductively isolated from other such groups.
  • This definition emphasizes reproductive isolation as a key component.
Limitations of Biological Species Concept
  • Challenges arise when trying to use this concept for various organisms:
    1. A. Bacterial species of the genus Escherichia
    2. B. Extinct species of rodent
    3. C. Asexually reproducing microbe
    4. D. None of the above
  • This indicates the concept's limitations in covering all types of organisms, particularly ones that do not conform to traditional sexual reproduction.

Alternative Species Concepts

Overview

There are several alternative species definitions to provide a broader understanding of the concept:

  • Phylogenetic Species Concept:
    • Focuses on shared, unique genetic histories.
  • Morphological Species Concept:
    • Classifies species based on similar body shapes.
  • Ecological Species Concept:
    • Defines species by their shared ecological niche.
Additional Species Concepts Listed
  1. Agamospecies Concept
  2. Cladistic Species Concept
  3. Cohesion Species Concept
  4. Composite Species Concept
  5. Evolutionary Significant Unit
  6. Evolution