Life in transition: the evolutionary consequences of ecological and habitat shifts

转型中的生命：生态和栖息地变化的进化后果

• 批准号: RGPIN-2016-06199
• 负责人: Adamowicz, Sarah
• 金额: $ 2.04万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709785
• 关键词: Life; transition; evolutionary; consequences; ecological

Major transitions in habitat and lifestyle traits have featured prominently in the history of life and have shaped the distribution of biodiversity on Earth. Some kinds of transitions have occurred numerous times independently, such as between marine and fresh waters and between predatory and herbivorous feeding modes. Such transitions that are represented by repeated, evolutionarily independent events provide valuable opportunities -- i.e. natural experiments -- to study the predictability of evolutionary responses. My overarching research objective is to elucidate the evolutionary causes and consequences of repeated transitions. Firstly, my students and I will assess the degree to which transitions impact rates of molecular evolutionary change through time, with a focus upon insects and aquatic invertebrates. We will quantify variability in rates of molecular evolution and test whether rates vary systematically in association with key habitat (e.g. marine/freshwater, benthic/planktonic, terrestrial/aquatic) and lifestyle (e.g. carnivorous/herbivorous, eusocial/solitary, parasitic/free-living) transitions in evolution. This work will represent a substantial step forward in molecular rates research by modeling rate variation across entire phylogenetic trees and by simultaneously investigating the strength of multiple factors in a multivariate context. Secondly, we will study molecular evolution associated with multiple types of aquatic habitat transitions, each representing a difference between a lower-extinction vs. a higher-extinction environment: ancient lakes vs. surrounding freshwaters, flowing vs. standing waters, and lakes vs. ponds. Using phylogenetically paired sister lineages differing in habitat occupancy, these various habitat regimes will be investigated for their potential association with elevated molecular diversity, population genetic structure, molecular evolutionary rate, and extent of genetic cohesion (vs. clustering into discrete groupings). The results of this work will contribute to understanding the impacts of habitat transitions upon molecular evolution within aquatic life. Furthermore, by explicitly investigating the hypothesis that extinction is important for generating discrete genetic groupings, this work also will contribute towards resolving a puzzle as to why so many taxa exhibit a "barcode gap", which is the disjunction often observed between intraspecific vs. interspecific pairwise DNA sequence divergences. The results of these studies will reveal whether these transitions provoke general molecular evolutionary responses. Moreover, understanding systematic rate variability is crucial for all who rely upon the molecular clock to provide a timescale for life, including researchers studying macroevolution, biogeography, and climate change impacts using historical reconstructions.

栖息地和生活方式特征的重大转变在生命史上占有显著地位，并塑造了地球上生物多样性的分布。有些类型的转变已经独立地发生了很多次，比如在海洋和淡水之间，在捕食和食草之间。这种由重复的、进化上独立的事件所代表的转变提供了宝贵的机会——即自然实验——来研究进化反应的可预测性。我的首要研究目标是阐明重复过渡的进化原因和后果。