She was born in 1950 in Moratuwa and she has done her primary education at Princess of Wales College, Moratuwa and later entered Vishaka Vidyalaya, Colombo. Prof Yalagalage Nuwanrasie Amaramali Jayatunga obtained B.Sc. (Hons) Second Class (Lower Division) in Zoology, University of Peradeniya and M.Phil. from the University of Colombo, Sri Lanka and her Ph.D. in Freshwater Ecology from University of London, U.K.

Prof. Jayatunga was first appointed in 1974 as a Temporary Assistant Lecturer in the Department of Zoology, University of Peradeniya and in 1975 she joined as an Assistant Lecturer Department of Zoology in the University of Colombo and then promoted in 1983 as a Senior Lecturer Grade II in the Department of Zoology. Later in 1989, she was promoted to Senior Lecturer Grade I. In 1998 she was promoted to the post of Professor, and during 1987-1992 and 1994-2008 she served as the Co-ordinator of the M.Sc. Environmental science programme. Prof. Jayatunga was awarded the Commonwealth Academic Staff Scholarship, U.K. in 1983-1986.

Prof. Jayatunga possesses 20 Research Publications, 31 Research Communications and she has supervised 1 MPhil student, 15 M.Sc students, 25 undergraduates and 2 overseas undergraduates. She has done Editorial Work in Biodiversity of Medicinal Plants published by Environmental Committee in 1995, Recycling of Solid waste Published by Environmental Committee, SLAAS in 1994, Sinhala translation of chapter 7 and 8 on Natural resources of Sri Lanka Published by Mihikatha Institute in 1991, Animal Diversity ZOU 1261 Text book by the Open University of Sri Lanka. Prof. Jayatunga has Published Text book for G.C.E. Advanced Level Zoology with Prof. K.D.Arudpragasam and Centers of Endemism with special reference to that of Sri Lanka with Prof. M.R.Wijesinghe and a Monograph on Environmental Technology Products and services sector and has translated HNCE Biology text book Published by the Education Publications Departmentin 1976, 1977 & 1991. She has served in the capacity of Setter GCE AL Zoology paper, Translator Setter GCE AL Zoology paper, Co-controller GCE AL Zoology paper and Controller GCE AL Zoology paper. She also has served as a resource person on several national and international workshops and seminars and has Memberships in Scientific Societies of national and international levels and has functioned as Office Bearer in Academic and Professional Associations such as SLAAS, Sri Lanka Association for Fisheries and Aquatic Resources, Physiological Society of Sri Lanka Parisarikayo. Prof. Jayatunga has contributed in Environmental Impact Assessments on 7 occasions as team leader, 3 occasions as Ecologist, Resources person for EIA training and 6 occasions as a member for TEC evaluation boards.

As a member of the department, she always put the department first and never hesitated to take any responsibility whenever such responsibility was required. Prof. Jayatunga joined the department when lectures were conducted in two languages, Sinhala, English. Since many lecturers, such as Prof. Arudpragasm, & Prof. Wignaraja were unable to deliver lectures in Sinhala, it was Prof. Jayatunga who had done all Sinhala lectures. In addition, she translated all the documents, including government circulars to Sinhala medium. This skill came in handy, and it was Prof.Jayatunaga who did almost every English to Sinhala translations in the department. Therefore, it can be said that, Prof. Jayatunga is as old as the department of Zoology. 

Prof. Jayatunga had a very sound knowledge in Basic Zoology, Limnology, Ecology and Environment Science. In the department, she is well known for her skills in dissections. She also played a key role in developing the Museum in the department while preparing an invaluable collection of slides. It was mainly because of Prof. Jayaunga that the department received the JICA grant. Prof. Jayatunga was involved in GCE Advanced level Zoology paper for many years and she was the official Sinhala medium translator and the one who had drawn all the diagrams (such as Amphioxus or cross sections of the earthworm or the life cycle of the mosquito) in the Zoology paper. 

Perhaps one of the significant contributions, if not the biggest, to the department of Zoology made by Prof. Jayatunga was reviving the Environment Science Program. Apparently this department had two Academic Chairs, Chair in Fisheries Biology and a Chair in Environment Science. These two positions were held by two Foreigners and after they left, these two programs had become defunct and Prof. Jayatunga took a leading role in reviving the M SC in Environment Science Program, which the department is conducting very successfully even today and the department is ever thankful to Prof. Jayatunga for keeping the environment science program going on and if not for her, even this program may have succumbed to a natural death. The department knows she has a very kind heart and sympathetic eye and whenever anybody has a problem he or she would rush to her and be assured they will get the best attention. Prof.Jayatunga had always been strength to the department, and she is a person who would take any responsibility without any hesitation.