The thermal performance curve (TPC) provides a mathematical and physiological framework for predicting how shifts in temperature are expected to impact population persistence in the face of global climate change. Yet, we lack knowledge of the mechanisms that translate thermal performance of molecular, cellular and individual level traits to population dynamics. Here we fit TPCs for population growth rate, estimated using life-table analyses, and for its underlying life-history and physiological components, including female fecundity, development rate, survivorship, metabolic rate and mitochondrial function using an outbred population of the fruit fly Drosophila melanogaster. We find that the activation energy estimated from TPCs increases from the molecular to the population level. Flies develop rapidly at higher temperatures, but this trades off with survivorship and fecundity, generating a TPC for population growth rate that is relatively narrow and sits in between the TPCs for female fecundity and development rate. The rich data gathered for insect life-table analyses reveal a thermal-dependent maternal age effect on offspring survivorship; when developed at intermediate temperatures, females can maintain fecundity and higher offspring survivorship across a larger fraction of their lifespan. We will present preliminary results on how TPCs across levels respond to thermal lab evolution. We will discuss how our research may provide a predictive framework for forecasting the dynamic responses to environmental change from thermal metabolic responses through a series of currently unknown nested functions up to population level responses.