1. Species Concepts

2. What makes each an individual species? Consider the following… Painted Bunting Roseate Spoonbill Barn Owl Northern Mockingbird Bald Eagle Common Loon Wood Thrush Canada Goose

3. Why identify species? A few reasons: – Scientific communication: for scientists to categorize and communicate their work on particular organisms – Phylogeny: to study and determine what makes groups unique and how organisms are related to one another – Conservation: to track the status and diversity of populations within an ecosystem

4. What is a species? According to the Oxford English Dictionary, a species is: “A group or class of animals or plants (usually constituting a subdivision of a genus) having certain common and permanent characteristics which clearly distinguish it from other groups.” But, what qualifies as “clearly distinct”?

5. Species Concepts Scientists have developed various ideas on how to best define a species. Here are a few of the over 20 possible species concepts: BIOLOGICAL SPECIES CONCEPT ECOLOGICAL SPECIES CONCEPT MORPHOLOGICAL SPECIES CONCEPT PHENETIC SPECIES CONCEPT RECOGNITION SPECIES CONCEPT PHYLOGENETIC SPECIES CONCEPT

6. What defines a species?

7. This general idea was revived later with more statistical rigor as the Phenetic Species Concept Morphological Species Concept A set of distinct physical features of a population of animals which sets it apart from others May be applied to both sexual and asexual organisms and fossils Strengths? Weaknesses?

8. Biological Species Concept Proposed by Ernst Mayr in 1942 A population whose members can successfully breed with one another in a natural environment, and not with another species

9. Biological Species Concept While a strong delimitation, the biological species concept continues to face discussion for the following reasons….. – Some organisms reproduce through binary fission, fragmentation, regeneration, budding, or other asexual means – Mating may be possible, yet hybrids sterile or unable to produce offspring successfully Other Weaknesses?

10. Examples of Hybridization Lazuli Bunting X Indigo Bunting Tufted Titmouse X Black-Capped Chickadee Northern Goshawk X Cooper’s Hawk

11. Reproductive Isolating Mechanisms Pre-mating or Pre-zygotic Post-mating or Post- zygotic Ecological, temporal, or behavioral (courtship songs or displays) barriers to isolation Hybrid inviability, sterility, or reduced fitness of hybrid offspring

12. Phylogenetic Species Concept Smallest set of organisms that share an ancestor and can be distinguished from other such sets Subspecies not recognized – Strengths: considers ancestry, genetic similarity, evolutionary process – Weaknesses: does not consider reproductive habits

13. Ecological Species Concept Focus of species characterization is on similarity of niche and ecological role – Strengths: considers species’ role in an ecosystem – Weaknesses: geographically widespread populations that don’t actually interbreed may be considered the same species

14. Case Study: Ensatina salamanders Find a group of 3 other classmates Take 10 minutes to look for information on these salamanders Then, discuss your group findings for 5 minutes and be ready to share your thoughts with the class! How would each species concept describe these salamanders? Which categorization do you think is best, and why?

15. In Conclusion The categorization and maintenance of species records is important for science and conservation For identifying an individual species, typically scientists will first consider Biological Species Concept, then descent from common ancestry and genotypic and phenotypic cohesion Species concepts are still subject to debate