Cecilia Leonor Jiménez Sierra is PhD on Biology with specialty in Ecology of populations. She has taught at the Universidad Nacional Autónoma de Mexico (FES-Zaragoza) for 19 years and now she is a Research Professor at the Universidad Autónoma Metropolitana, Iztapalapa. She is the author of 46 research articles and has published six chapters in diverse books. Her field of interest is the conservation of natural resources, especially in semi-arid areas, including the human and nature relationships. She has directed several projects on population dynamics of endangered species cacti which have been supported by SEMARNAT and CONABIO and has directed 57 undergraduate’s terminal investigations and 13 post-doctoral theses.