The branch of science concerned with the interrelationship of organisms and their ENVIRONMENT, especially as manifested by natural cycles and rhythms, community development and structure, interactions between different kinds of organisms, geographic distributions, and population alterations. (Webster's, 3d ed)
A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)
Chemical substances, excreted by an organism into the environment, that elicit behavioral or physiological responses from other organisms of the same species. Perception of these chemical signals may be olfactory or by contact.
Body builds determined on the basis of certain physical characteristics of body shape and BODY COMPOSITION. A somatotyping appraisal is a composite rating of the three basic body types: ectomorph (thin physique), endomorph (rounded physique), and mesomorph (athletic physique).
A potentially life-threatening condition in which EMBRYO IMPLANTATION occurs outside the cavity of the UTERUS. Most ectopic pregnancies (>96%) occur in the FALLOPIAN TUBES, known as TUBAL PREGNANCY. They can be in other locations, such as UTERINE CERVIX; OVARY; and abdominal cavity (PREGNANCY, ABDOMINAL).
