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Organism. An organism is defined in a medical dictionary as any living thing that functions as an individual. [1] Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have been proposed to define what is an organism.
Lifeis a quality that distinguishes matterthat has biological processes, such as signalingand self-sustaining processes, from matter that does not. It is defined descriptively by the capacity for homeostasis, organisation, metabolism, growth, adaptation, response to stimuli, and reproduction. All life over time eventually reaches a state of ...
A species ( pl.: species) is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. [ 1] It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity.
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: asexual and sexual . In asexual reproduction, an organism can reproduce without the involvement of another organism.
An individual is one that exists as a distinct entity. Individuality (or self-hood) is the state or quality of living as an individual; particularly (in the case of humans) as a person unique from other people and possessing one's own needs or goals, rights and responsibilities. The concept of an individual features in many fields, including ...
Ecosystem processes are the net effect of the actions of individual organisms as they interact with their environment. Ecological theory suggests that in order to coexist, species must have some level of limiting similarity —they must be different from one another in some fundamental way, otherwise, one species would competitively exclude the ...
The theory of recapitulation, also called the biogenetic law or embryological parallelism —often expressed using Ernst Haeckel 's phrase " ontogeny recapitulates phylogeny "—is an historical hypothesis that the development of the embryo of an animal, from fertilization to gestation or hatching ( ontogeny ), goes through stages resembling or ...
Behavior ( American English) or behaviour ( British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as well as the inanimate physical environment. It is the computed response of the system or organism to ...