DSST Environmental Science Exam Preparation Questions and Answers

Biodiversity It is a term used to describe the diversity (variations) of genes, species, and ecosystems within a region. Population A group of the same species living in the same geographic region at the same time. Mutualism A relationship between organisms that is beneficial to both organisms. In many cases of mutualism, the species cannot live without each other. Parasitism A relationship in which one organism, the parasite, lives in or on another organism, the host. The parasite generally derives nourishment from the host, and the host is harmed, or more rarely eventually killed, by the parasite. Symbiosis A close, long-lasting physical relationship between two species. The two species are in close physical contact, and at least one of them derives some benefit from the relationship. Species Diversity It is a measure of the number of various species within a given area. Ecosystems These are a complex network of interrelationships between abiotic and biotic factors. Community All of the interacting populations of different species that live in a given area at the same time. Predation It is when one organism, known as the predator, kills and eats another organism, known as the prey. The predator benefits from this relationship, and the prey is harmed. Commensalism A relationship between organism in which one organism benefits and the other is not affected. Competition It is when species compete for limited resources such as food, water, sunlight, and territory. Competition is classified as intraspecific if it occurs between members of the same species and interspecific if it occurs between members of different species.