Category: Biology Dictionary E

Ecological Succession Definition Ecological succession is a term developed by botanists to describe the change in structure of a community of different species, or ecosystem. The concept of ecological succession arose from a desire to understand how large and complex ecosystems like forests can exist in places known to be recently formed, such as volcanic islands. […]

Ecological Pyramid Definition An ecological pyramid is a graphical representation of the relationship between different organisms in an ecosystem. Each of the bars that make up the pyramid represents a different trophic level, and their order, which is based on who eats whom, represents the flow of energy. Energy moves up the pyramid, starting with the primary producers, […]

Ecological Niche Definition In ecology, a niche is the role or job of a species in a habitat. The word niche comes from the French word nicher, which means “to nest.” An ecological niche describes how a species interacts with, and lives in, its habitat. Ecological niches have specific characteristics, such as availability of nutrients, temperature, […]

Echinoderm Definition An echinoderm is a member of the phylum Echinodermata which contains a number of marine organisms recognized by their pentamerous radial symmetry, calcareous endoskeleton, and a water vascular system which helps operate their small podia. Podia are small extensions of flesh which are operated by water pressure and muscles, and controlled by the nervous system of the echinoderm. […]

Ecdysis Definition Ecdysis comes from the Greek word ekdusis, which means “put off.” It describes the process by which arthropods and insects shed their outer cuticle (exoskeleton), or how reptiles shed their old skin. This process is necessary in order for the organism to grow. The term for the cuticle or skin that is lost is exuviae. […]

Ear Definition The ear is the organ found in animals which is designed to perceive sounds. Most animals have some sort of ear to perceive sounds, which are actually high-frequency vibrations caused by the movement of objects in the environment. The human ear picks up and interprets high-frequency vibrations of air, while the sound-sensing organs […]