Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for +publisher:"University of Toronto" +contributor:("Weir, Jason"). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


University of Toronto

1. Pulido-Santacruz, Paola. Dynamics of Speciation in Neotropical Birds: Diversification Rates, Introgression and Reproductive Isolation.

Degree: PhD, 2017, University of Toronto

Tropical rainforests â covering 7% of the earth's surface â are areas of exceptionally high biodiversity compared to other ecosystems. However, no consensus has been reached as to the primal cause of high tropical diversity. In this thesis, I used a combination of phylogenetic and population genetic methods to address whether speciation is an important driver of diversification patterns and to determine the genetic architecture of reproductive isolation and the frequency of introgression during the diversification process in the species-rich Neotropics. I developed and fit a character-state dependent diversification model to a global avian phylogeny and found consistent support across replicate clades for extinction as a key driver of species richness gradients. In contrast, an association between speciation or dispersal rates with species richness was not consistently found. To better understand the process of speciation in the tropics, I studied reproductive isolation in two genera of suboscine birds. My results showed that pre-zygotic reproductive barriers play a less important role in the tropical speciation process than at high latitudes, with reproductive isolation driven largely by post-zygotic genetic incompatibilities. I also found evidence of frequent introgression events during the diversification process in the Neotropical genus Dendrocincla. My analyses showed different instances of historical introgression events among closely and distantly related lineages of Dendrocincla, demonstrating that introgression may often be a common phenomenon during the diversification process in the Neotropics. These results contribute to our understanding of the evolutionary processes that drive diversification and how speciation evolves in areas of high species richness.

2019-11-06 00:00:00

Advisors/Committee Members: Weir, Jason T, Ecology and Evolutionary Biology.

Subjects/Keywords: Birds; Extinction; Hybridization; Neotropics; Reproductive Isolation; Speciation; 0329

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Pulido-Santacruz, P. (2017). Dynamics of Speciation in Neotropical Birds: Diversification Rates, Introgression and Reproductive Isolation. (Doctoral Dissertation). University of Toronto. Retrieved from http://hdl.handle.net/1807/97193

Chicago Manual of Style (16th Edition):

Pulido-Santacruz, Paola. “Dynamics of Speciation in Neotropical Birds: Diversification Rates, Introgression and Reproductive Isolation.” 2017. Doctoral Dissertation, University of Toronto. Accessed January 23, 2020. http://hdl.handle.net/1807/97193.

MLA Handbook (7th Edition):

Pulido-Santacruz, Paola. “Dynamics of Speciation in Neotropical Birds: Diversification Rates, Introgression and Reproductive Isolation.” 2017. Web. 23 Jan 2020.

Vancouver:

Pulido-Santacruz P. Dynamics of Speciation in Neotropical Birds: Diversification Rates, Introgression and Reproductive Isolation. [Internet] [Doctoral dissertation]. University of Toronto; 2017. [cited 2020 Jan 23]. Available from: http://hdl.handle.net/1807/97193.

Council of Science Editors:

Pulido-Santacruz P. Dynamics of Speciation in Neotropical Birds: Diversification Rates, Introgression and Reproductive Isolation. [Doctoral Dissertation]. University of Toronto; 2017. Available from: http://hdl.handle.net/1807/97193

2. Lawson, Adam Matthew. Latitudinal Gradients in Climatic Niche Evolution.

Degree: 2014, University of Toronto

Either tropical niche divergence or tropical niche conservatism could drive the latitudinal diversity gradient. Greater niche divergence in the tropics could accelerate reproductive isolation leading to more rapid species formation. Alternatively, latitudinal asymmetry in niche conservatism, whereby tropical species are more conserved than high latitude species, could promote more dispersal in to than out of the tropics, leading to greater tropical richness. Here I test whether rates of climatic niche evolution vary across the latitudinal gradient for 164 closely related pairs of species. Using the evolutionary ages at which sister species diverge, and the niche divergence between them, I applied Brownian motion models to test whether rates of climatic niche evolution varied with latitude. My results indicate that climatic niche conservatism is strongest in the tropics. This suggests that the latitudinal diversity gradient is driven by the inability of tropical to adapt to temperate climates and colonize non-tropical latitudes.

MAST

Advisors/Committee Members: Weir, Jason, Ecology and Evolutionary Biology.

Subjects/Keywords: climatic niche; latitudinal gradients; species richness; New Wolrd birds; New World mammals; evolutionary rates; 0329

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Lawson, A. M. (2014). Latitudinal Gradients in Climatic Niche Evolution. (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/44035

Chicago Manual of Style (16th Edition):

Lawson, Adam Matthew. “Latitudinal Gradients in Climatic Niche Evolution.” 2014. Masters Thesis, University of Toronto. Accessed January 23, 2020. http://hdl.handle.net/1807/44035.

MLA Handbook (7th Edition):

Lawson, Adam Matthew. “Latitudinal Gradients in Climatic Niche Evolution.” 2014. Web. 23 Jan 2020.

Vancouver:

Lawson AM. Latitudinal Gradients in Climatic Niche Evolution. [Internet] [Masters thesis]. University of Toronto; 2014. [cited 2020 Jan 23]. Available from: http://hdl.handle.net/1807/44035.

Council of Science Editors:

Lawson AM. Latitudinal Gradients in Climatic Niche Evolution. [Masters Thesis]. University of Toronto; 2014. Available from: http://hdl.handle.net/1807/44035

.