Short answers, pulled from the story.
The German scientist Ernst Haeckel introduced the word ecology into scientific discourse in 1866. He published this term in his book Generelle Morphologie der Organismen to describe the study of organisms and their environment.
Herodotus described mutualism when he noted that Nile crocodiles opened their mouths for sandpipers to pluck leeches from them. This observation provided early nutrition for the bird and oral hygiene for the reptile.
A primary law of population ecology is the Malthusian growth model which states that a population will grow or decline exponentially if environmental conditions remain constant. Simplified models usually start with four variables: death, birth, immigration, and emigration.
Biodiversity describes the diversity of life from genes to ecosystems and spans every level of biological organization. It includes species diversity, ecosystem diversity, and genetic diversity that affect complex ecological processes.
Modern ecology first attracted substantial scientific attention toward the end of the 19th century. Ellen Swallow Richards adopted the term oekology in the U.S. as early as 1892.