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id="docs-internal-guid-ca367bd4-7fff-0f8a-06c9-c4fd80277c98">
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style="line-height:1.38;margin-top:0pt;margin-bottom:0pt;"><span style="font-size:11pt;font-family:Arial;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Biology Department Virtual Seminar</span></p>
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style="line-height:1.38;margin-top:0pt;margin-bottom:0pt;"><span style="font-size:11pt;font-family:Arial;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Thursday, January 7 at Noon</span></p>
<p dir="ltr"
style="line-height:1.38;margin-top:0pt;margin-bottom:0pt;"><span style="font-size:11pt;font-family:Arial;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Zoom link: <a class="moz-txt-link-freetext" href="https://whoi-edu.zoom.us/j/98783604265?pwd=dS9TclAwekRyMHp1OWdUSU4zaVNQQT09">https://whoi-edu.zoom.us/j/98783604265?pwd=dS9TclAwekRyMHp1OWdUSU4zaVNQQT09</a></span></p>
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<p dir="ltr"
style="line-height:1.38;margin-top:0pt;margin-bottom:0pt;"><span style="font-size:11pt;font-family:Arial;color:#000000;background-color:transparent;font-weight:700;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Silke Van Daalen, WHOI Postdoctoral Scholar</span></p>
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<p dir="ltr"
style="line-height:1.38;margin-top:0pt;margin-bottom:0pt;"><span style="font-size:11pt;font-family:Arial;color:#000000;background-color:transparent;font-weight:700;font-style:italic;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">A demographic and evolutionary analysis of maternal age effects in rotifers at the individual and population level</span></p>
<p dir="ltr" style="line-height:1.38;text-indent:
36pt;margin-top:0pt;margin-bottom:0pt;"><span style="font-size:11pt;font-family:Arial;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">Maternal age (the age of the mother at the birth of her offspring) can influence, positively or negatively, the quality of offspring, affecting any of the vital rates. Maternal age is therefore a form of heterogeneity among individuals within a population and affects population-level dynamics and evolutionary processes. In order to explore the effects of maternal age, we develop matrix models that classify individuals by both age and maternal age. We fit these models to data from individual-based culture experiments on the aquatic invertebrate, Brachionus manjavacas (Rotifera). We manipulated laboratory survival and fertility estimates to produce stationary or nearly stationary populations, and to alter the magnitude of maternal age effects. </span></p>
<p dir="ltr" style="line-height:1.38;text-indent:
36pt;margin-top:0pt;margin-bottom:0pt;"><span style="font-size:11pt;font-family:Arial;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">At the population-level, we show that individuals born to older mothers see a fitness expressed primarily as a decrease in fertility. We use the models representing the laboratory, low-fertility and low-survival environments, with or without maternal age, to estimate selection gradients on survival and fertility, which measure the strength of selection. In all cases, selection gradients decrease with both age and maternal age, suggesting evolution can lead to such a maternal age effect as an example of maternal effect senescence. </span></p>
<p dir="ltr" style="line-height:1.38;text-indent:
36pt;margin-top:0pt;margin-bottom:0pt;"><span style="font-size:11pt;font-family:Arial;color:#000000;background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre;white-space:pre-wrap;">When we shift perspective to the individual level, we investigate the effect of heterogeneity in vital rates due to maternal age on mean and variance in lifetime reproductive output. By turning the matrix model into Markov chains, we quantify the contribution of heterogeneity and individual stochasticity, i.e. luck experienced while moving through the life cycle, to variance in LRO. We conclude that heterogeneity, even with large effects on vital rates, may not make an important contribution to variance in LRO. The contribution of heterogeneity depends on the environmental conditions that determine the vital rates. </span></p>
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<pre class="moz-signature" cols="72">--
Margot McKlveen | she/her
Senior Administrative Assistant
Woods Hole Oceanographic Institution
Redfield Building Room 305 | MS 32
266 Woods Hole Rd.
Woods Hole, MA 02543
508-289-2334
<a class="moz-txt-link-abbreviated" href="mailto:mmcklveen@whoi.edu">mmcklveen@whoi.edu</a></pre>
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