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BIO220H1 Study Guide - Final Guide: Photoperiodism, Natural Selection, Vernalization

Course Code
John Stinchcombe
Study Guide

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Lab 1: Phenotypic plasticity and adaptive evolution contribute to advancing
flowering phenology in response to climate change
Combine continuous 38 yr field survey w/ quantitative genetic field experiments
oAssess adaptation in context of climate change
Focused on mustard native of US Rocky Mountains
Look at flowering phenology
oEarlier flowering b/c climate change
In seasonal environment, plants reproduce in narrow timeframe
oCan’t emerge too early
= fitness b/c frost damage to developing floral tissues, no pollinators,
intense herbivory, not enough resources to make reproductive organs
oCan’t flower too late
Won’t be able to complete reproductive cycles before winter/drought
= stabilizing selection favours evolution of intermediate flowering time
But recent analyses find directional selection for earlier flowering in flower spp
Plants flowering earlier now:
oRising temperatures
oAltered precipitation regimes
oElevated atm CO2 concentrations
Earlier flowering time = symptom of rapidly changing climatic conditions
o extinction risk if rate of climate change > rate of adaptive phenotypic change
Diff spp. = Diff way of coping w/ climate changes:
oMigrate to better environments
oCope w/ changes in situ (plasticity/adaptive evolution)
Plasticity crucial for short term
Adaptive evolution = long term
But sustained directional selection via climate change could
deplete population of genetic variation needed for continued
This study:
oIntegrates multiple lines of evidence explore NS in context of global warming
oQuantify phenotypic + evolutionary changes in flowering time of mustard
Assess long-term changes in timing of flowering
Quantify relationship between flowering phenology + environmental
Examine selection on flowering phenology
Estimate potential for adaptive evolutionary responses to climate change
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