1. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Ecological Species Concept

2. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Ecological Species Concept - In responding to selection, populations diverge and play unique roles in the environment - filling different niches. This ecological specialization will be reflected in physiological, morphological, or behavioral differences between populations. Hawaiian Honeycreepers

3. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Ecological Species Concept - In responding to selection, populations diverge and play unique roles in the environment - filling different niches. This ecological specialization will be reflected in physiological, morphological, or behavioral differences between populations. - Our classic example of "Character Displacement", where the morphology changes as a function of the environment - most notably the presence of other species such as competitors or predators.

4. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Ecological Species Concept - In responding to selection, populations diverge and play unique roles in the environment - filling different niches. This ecological specialization will be reflected in physiological, morphological, or behavioral differences between populations. - Our classic example of "Character Displacement", where the morphology changes as a function of the environment - most notably the presence of other species such as competitors or predators. - In the presence of a competitior, G. fortis uses a different range of seeds and is a different ecological species than where it occurs alone. It plays a different role in the environment and fills a different niche.

5. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Striking a Balance

6. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Striking a Balance - So what preserves the integrity of species - reproductive isolation or ecological isolation? These are often correlated, so it is tough to tease their independent contributions apart. Geographic or ecological isolation Genetic divergence and reproductive isolation

7. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Striking a Balance - So what preserves the integrity of species - reproductive isolation or ecological isolation? These are often correlated, so it is tough to tease their independent contributions apart. - Conundrums: - Selection can produce divergence even when their IS gene flow. (polymorphism)

8. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Striking a Balance - So what preserves the integrity of species - reproductive isolation or ecological isolation? These are often correlated, so it is tough to tease their independent contributions apart. - Conundrums: - Selection can produce divergence even when their IS gene flow. (polymorphism) - Selection can produce uniformity in absence of gene flow (convergence)

9. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Striking a Balance - So what preserves the integrity of species - reproductive isolation or ecological isolation? These are often correlated, so it is tough to tease their independent contributions apart. - Conundrums: - Selection can produce divergence even when their IS gene flow. (polymorphism) - Selection can produce uniformity in absence of gene flow (convergence) - And, gene flow can also keep two populations in different environments similar.

10. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Striking a Balance - So what preserves the integrity of species - reproductive isolation or ecological isolation? These are often correlated, so it is tough to tease their independent contributions apart. - Conundrums: - Selection can produce divergence even when their IS gene flow. (polymorphism) - Selection can produce uniformity in absence of gene flow (convergence) - And, gene flow can also keep two populations in different environments similar. - For bacteria/archaeans, lateral gene transfer (gene flow) creates new species, with a new unique complement of genes.

11. Species and Speciation I. Species Concepts A. Morphological Species Concept B. Biological Species Concept - Mayr 1942 C. Evolutionary/Phylogenetic Species concepts D. Striking a Balance - So what preserves the integrity of species - reproductive isolation or ecological isolation? These are often correlated, so it is tough to tease their independent contributions apart. - Conundrums: - Selection can produce divergence even when their IS gene flow. (polymorphism) - Selection can produce uniformity in absence of gene flow (convergence) - And, gene flow can also keep two populations in different environments similar. - For bacteria/archaeans, lateral gene transfer (gene flow) creates new species, with a new unique complement of genes. - Need to appreciate that the relative importance of different factors may vary depending on the organism - does it have high dispersal and isolation probability? Can it change rapidly? These things will vary with the type of organisms (large mammals vs. insects).

12. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology

13. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology - correlated phenotypic characters. Quantitative characteristics can have bimodal distributions. However, it is unusual for a single species to be bimodal for lots of characters. H. erato H. melpomene Wing Pattern Wing Shape

14. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology - correlated phenotypic characters. Quantitative characteristics can have bimodal distributions. However, it is unusual for a single species to be bimodal for lots of characters. H. melpomene - If you observe this (big ones are red, with wispy antenna, small wings and fast flight; small ones are blue with short antenna, large wings and slow flight), then you probably have two reproductively isolated groups. H. eratoH. melpomene Body Size Wing Shape

15. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology - correlated phenotypic characters. Quantitative characteristics can have bimodal distributions. However, it is unusual for a single species to be bimodal for lots of characters. - If you observe this (big ones are red, with wispy antenna, small wings and fast flight; small ones are blue with short antenna, large wings and slow flight), then you probably have two reproductively isolated groups. - may miss morphologically similar sibling species, or lump polymorphic species.

16. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology - correlated phenotypic characters. Quantitative characteristics can have bimodal distributions. However, it is unusual for a single species to be bimodal for lots of characters. - If you observe this (big ones are red, with wispy antenna, small wings and fast flight; small ones are blue with short antenna, large wings and slow flight), then you probably have two reproductively isolated groups. - may miss morphologically similar sibling species, or lump polymorphic species. - want to focus on traits of little selective value, or copulatory organs

17. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis - Genetic Distance - distance correlates with divergence that can occur both before and after reproductive isolation. So, there is a fairly continuous function of declining similarity as reproductive isolation develops, dependent on average size of the populations. Within a group, often we see 'species' associated with a particular amount of genetic distance.

18. Coyne and Orr. 1989. Patterns of speciation in Drosophila. Evolution 43: 362-381. A summary of hybridization experiments involving 119 pairs of closely related Drosophila species. Prezygotic Isolation: Mate Selection: I = 1 - ( number of heterospecific matings) / (number of homospecific matings) Post-zygotic Isolation: avg: Offspring inviable or sterile (1) or viable and fertile (0)

19. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis - Genetic Distance - Compute Nei's Genetic distance: D = -ln [ ∑p i 1p i 2/ √ ∑p i1 2 ∑ p i2 2 ] - So, for Population 1 and 2: - ∑p i 1p i 2 = (0.7*0.2) + (0.3*0.8) = 0.38 - denominator = √ (.49+.09) * (.04+.64) = 0.628 D 12 = -ln (0.38/0.62) = 0.50 - calculate these values FOR EACH locus, and then average the I's or D's together to get the final Genetic Distance. The more loci, the better. p1 = 0.7 q1 = 0.3 p2 = 0.2 q2 = 0.8

20. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis - Genetic Distance - distance correlates with divergence that can occur both before and after reproductive isolation. So, there is a fairly continuous function of declining similarity as reproductive isolation develops, dependent on average size of the populations. Within a group, often we see 'species' associated with a particular amount of genetic distance. - Compute Nei's Genetic Distance - CAVEATS:

21. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis - Genetic Distance - distance correlates with divergence that can occur both before and after reproductive isolation. So, there is a fairly continuous function of declining similarity as reproductive isolation develops, dependent on average size of the populations. Within a group, often we see 'species' associated with a particular amount of genetic distance. - Compute Nei's Genetic Distance - CAVEATS: - Genetic diffs do not necessarily correlate with morphological diffs; small genetic diffs can mean large morphological change (developmental genes), or large genetic differences can be hidden by morphological similarity (norms of reaction).

22. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis - Genetic Distance - distance correlates with divergence that can occur both before and after reproductive isolation. So, there is a fairly continuous function of declining similarity as reproductive isolation develops, dependent on average size of the populations. Within a group, often we see 'species' associated with a particular amount of genetic distance. - Compute Nei's Genetic Distance - CAVEATS: - Genetic diffs do not necessarily correlate with morphological diffs; small genetic diffs can mean large morphological change (developmental genes), or large genetic change can be hidden by morphological similarity (norms of reaction). - Still, genetic similarity is a more direct measure of degree of isolation.

23. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis - Genetic Distance - distance correlates with divergence that can occur both before and after reproductive isolation. So, there is a fairly continuous function of declining similarity as reproductive isolation develops, dependent on average size of the populations. Within a group, often we see 'species' associated with a particular amount of genetic distance. - Compute Nei's Genetic Distance - CAVEATS: - Genetic diffs do not necessarily correlate with morphological diffs; small genetic diffs can mean large morphological change (developmental genes), or large genetic change can be hidden by morphological similarity (norms of reaction). - Still, genetic similarity is a more direct measure of degree of isolation. - Also, there is no suggestion that divergence in these loci CAUSE speciation. Rather, these loci are simply used as 'markers' or indicators of general genetic distance.

24. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis C. Hybrid Analyses

25. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis C. Hybrid Analyses - Create hybrids and examine their fertility. Infertility may be due to: - Epistatic interactions between loci derived from different parents. Maybe species one has A1A1B1B1 and species 2 has A2A2B2B2, and maybe A1 and B1 don't work together. If one is a sex linked gene, then sterility might be sex-specific.

26. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis C. Hybrid Analyses - Create hybrids and examine their fertility. Infertility may be due to: - Epistatic interactions between loci derived from different parents. Maybe species one has A1A1B1B1 and species 2 has A2A2B2B2, and maybe A1 and B1 don't work together. If one is a sex linked gene, then sterility might be sex-specific. - Hybrids that receive different inversion chromosomes may have lower fitness because crossing over produces aneuploid gametes - with chromosomes that lack centromeres and are lost from the cell line.

27. The only functional gametes are those that DID NOT cross over – and preserve the parental combination of alleles Inversion (changes the order of genes on a chromosome)

28. Inversions in different populations of D. pseudoobscura (Dobzhansky& Sturtevant 1938)

30. Relative frequencies (percentages) of five chromosomal inversions in D. pseudoobscura in different geographic regions.

33. Species and Speciation I. Species Concepts II. Recognizing Species A. Morphology B. Genetic Analysis C. Hybrid Analyses - Create hybrids and examine their fertility. Infertility may be due to: - Epistatic interactions between loci derived from different parents. Maybe species one has A1A1B1B1 and species 2 has A2A2B2B2, and maybe A1 and B1 don't work together. If one is a sex linked gene, then sterility might be sex-specific. - Hybrids that receive different inversion chromosomes may have lower fitness because crossing over produces aneuploid gametes - with chromosomes that lack centromeres and are lost from the cell line. - Hybrids receiving chromosomes from parents with different reciprocal translocations may not have neat homologous sets.

34. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation

35. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers

36. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat)

37. Drosophila speciation on the Hawaiian Islands. Obbard D J et al. Mol Biol Evol 2012;29:3459-3473 © The Author 2012. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

39. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation

40. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation 3. Behavior Isolation - don't recognize one another as mates Western MeadowlarkEastern Meadowlark

41. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation 3. Behavior Isolation - don't recognize one another as mates 4. Mechanical isolation - genitalia don't fit; limit pollinators

42. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation 3. Behavior Isolation - don't recognize one another as mates 4. Mechanical isolation - genitalia don't fit 5. Gametic Isolation - gametes transfered but sperm can't fertilize egg; this is a common isolation mechanism in species that spawn at the same time

43. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation 3. Behavior Isolation - don't recognize one another as mates 4. Mechanical isolation - genitalia don't fit 5. Gametic Isolation - gametes transfered but sperm can't fertilize egg B. Post-Zygotic Isolation

44. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation 3. Behavior Isolation - don't recognize one another as mates 4. Mechanical isolation - genitalia don't fit 5. Gametic Isolation - gametes transfered but sperm can't fertilize egg B. Post-Zygotic Isolation 1. Genomic Incompatibility - zygote dies

45. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation 3. Behavior Isolation - don't recognize one another as mates 4. Mechanical isolation - genitalia don't fit 5. Gametic Isolation - gametes transfered but sperm can't fertilize egg B. Post-Zygotic Isolation 1. Genomic Incompatibility - zygote dies 2. Hybrid Inviability - F1 has lower survival Crazy hybrids

46. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation 3. Behavior Isolation - don't recognize one another as mates 4. Mechanical isolation - genitalia don't fit 5. Gametic Isolation - gametes transfered but sperm can't fertilize egg B. Post-Zygotic Isolation 1. Genomic Incompatibility - zygote dies 2. Hybrid Inviability - F1 has lower survival 3. Hybrid Sterility - F1 has reduced reproductive success Horse: 64 chromosomes Donkey: 62 chromosomes Mule: 63 chromosomes

47. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation A. Pre-Zygotic Barriers 1. Geographic Isolation (large scale or habitat) 2. Temporal Isolation 3. Behavior Isolation - don't recognize one another as mates 4. Mechanical isolation - genitalia don't fit 5. Gametic Isolation - gametes transfered but sperm can't fertilize egg B. Post-Zygotic Isolation 1. Genomic Incompatibility - zygote dies 2. Hybrid Inviability - F1 has lower survival 3. Hybrid Sterility - F1 has reduced reproductive success 4. F2 breakdown - F1's survive but F2's have incompatible combo's of genes

48. AABB x aabb F1: AaBb = ok F2: A-B- = ok A-bb = no aaB- = no aabb = ok

49. Species and Speciation I. Species Concepts II. Recognizing Species III. Making Species - Reproductive Isolation IV. Speciation