Biol 3350 1st Edition Lecture 24Outline of Last Lecture I. Biological Species ConceptII. Advantages and Disadvantages to Biological Species Concepta. Advantagesb. Disadvantages III. Morphospecies ConceptIV. Advantages and Disadvantages to Morphospecies Concepta. Advantagesb. DisadvantagesV. Phylogenetic Species ConceptVI. Advantages and Disadvantages to Phylogenetic Species Concepta. Advantagesb. DisadvantagesVII. Gray Treefrog Speciationa. Descriptionb. Biological Species Conceptc. Phylogenetic Species ConceptVIII. Reduction in gene flowIX. Reproductive isolationX. Premating isolating mechanismsOutline of Current Lecture I. Ecological Speciation in AllopatryII. Lizard clade AnguidaeIII. Crocodylidae CladeIV. Is the distribution of the chameleon clade reflective of vicariance or oceanic dispersal?V. Sympatric SpeciationVI. Speciation by Sexual SelectionVII. Lake Malawi CichlidsVIII. Ring speciesIX. Patterns of SpeciationX. Potential Outcomes of HybridsCurrent LectureI. Ecological Speciation in AllopatryThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. Each population will diverge through genetic drift or through natural selectionb. Hybrids usually have a lower fitness than either parentc. Individuals who don’t make the mistakes of producing hybrids will have a higher fitnessd. Vicariance – ancestral ranges of formerly continuous distributions have been fragmented by the formation of barriere. Dispersal – individuals have migrated across pre-existing barriers to create present distributionII. Lizard clade Anguidaea. Slender glass lizard current distribution reflects that this clade originated in Laurasiab. Then the clade dispersed into South America, which was part of GondwanaIII. Crocodylidae Cladea. Covered the areas that were part of Gondwanab. Vicariance through continental drift was hypothesized to be the adaptive means through these cladesIV. Is the distribution of the chameleon clade reflective of vicariance or oceanic dispersal?a. The oldest clades are in Madagascarb. Looked at the pattern of continental break up and tried to see if that pattern was congruent with the geographical locations of the current clades and their agesc. First break up was Africa and South Asia broke off of Gondwanad. In large, they were agreeing with Raxworthy in the most basal cladee. But thought the next most basal clade was in Africa, not Madagascar f. They were carried by ocean currents on floating vegetation rather than on continentsg. Both agrees and disagrees with Raxworthyh. A phylogeny is a hypothesisi. New information can change phylogeniesj. We now believe that they originated in Africak. Seychelles tiger chameleon distribution explained by dispersalV. Sympatric Speciationa. Population A is adapting to one type of habitat and population B is adapting to another, but they also have an overlapb. Assortative mating – like mates with likec. Three-spine sticklebacks:i. Benthic: mainly eats invertebrates, large body and few, short gill rakersii. Limentic: primarily exploits plankton, small body and many, long gill rakersiii. Limentic prefers to breed with its own kind, and benthic prefers to breed with its own kind as welliv. Very little breeding between the two types of speciesv. Byproduct reproductive isolation is the result of the preference for to breed with their own sizeVI. Speciation by Sexual Selectiona. Inter-sexual selection – mating preferencesb. Less and less odds of interbreeding between divergent populationsc. Link between preference and male expression of the traitVII. Lake Malawi Cichlidsa. The species that inhabit deep water have opsins that are more sensitive to red lightb. When the water quality is low, the males look similar to each other à hybrid zone, no real differencec. When live in habitats of high water quality, females have distinct preference à red females prefer red males, and blue females prefer blue malesd. Natural selection and sexual selection combine and work together à common way in which new species ariseVIII. Ring speciesa. The most basal of the salamander group is found up in Northern Californiab. Zones of hybridization and interbreeding between most of the adjacent types of species, but no interbreeding between the bottom two speciesc. Adaptive radiation down the cost and an adaptive radiation down the eastern side à the southern most 2 species do not interbreedd. Sexual selection and natural selection are working hand in hand, because there are costs to mistakes and breeding with the wrong typeIX. Patterns of Speciationa. Ratsnakes entered N. America and there were no other advanced snakes inhabiting the area, so there was a wide range of niches to covered à slowed down when niches were all occupiedb. Early mammalian evolution à at first there were just primarily small species & when dinosaurs when extinct, there was a burst of speciationX. Potential Outcomes of Hybridsa. Hybrid fitness is lower than parentalsi. Hybrids go extinctii. Parental species divergeb. Hybrid fitness is equal to parentalsi. Hybrids are maintained in relatively wide zonec. Hybrid fitness is higher than parentalsi. New hybrid species may