Ecology (from Greek: οίκος, oikos, "household"; and λόγος, logos, "knowledge") is the scientific study of the distribution and abundance of living organisms and the interactions among organisms and between organisms and their environment. The environment of an organism includes both physical properties, which can be described as the sum of local abiotic factors such as insolation (sunlight), climate, and geology, and biotic factors, which are other organisms that share its habitat.The word "ecology" is often used more loosely in such terms as social ecology and deep ecology and in common parlance as a synonym for the natural environment or environmentalism. Likewise "ecologic" or "ecological" is often taken in the sense of environmentally friendly.The term ecology or oekologie was coined by the German biologist Ernst Haeckel in 1866, when he defined it as "the comprehensive science of the relationship of the organism to the environment." Haeckel did not elaborate on the concept, and the first significant textbook on the subject (together with the first university course) was written by the Danish botanist, Eugenius Warming. For this early work, Warming is often identified as the founder of ecology.