All organisms have a position within an ecosystem. The complete set of living and nonliving factors—including food resources, climate, and terrain—that define the position of a given organism are collectively referred to as the organism’s ecological niche.

The human need for self-esteem has long intrigued psychologists, leading to the development of several theories that explore its evolutionary and functional significance. Among the most influential are the sociometer, hierometer, and terror management theories. Each offers a unique perspective on why people strive for self-worth and how it shapes behavior and social interaction.Sociometer TheoryAccording to sociometer theory, self-esteem functions as an internal gauge of social acceptance. It...

Locus of control describes how individuals perceive the causes of events in their lives, influencing motivation and well-being. Introduced by Julian Rotter in 1954, it is categorized into internal and external locus of control.Internal Locus of ControlIndividuals with an internal locus of control believe their actions determine outcomes, fostering responsibility, self-efficacy, and motivation. For example, an employee may attribute career success to hard work. Research links this mindset to...

Self-concept is the cognitive and emotional understanding individuals hold about their identity. It evolves through various developmental stages, beginning in infancy and maturing as children grow. This concept influences how individuals perceive their abilities, interact with others, and manage challenges throughout life.
Infancy and Emerging Recognition
During infancy, self-concept is virtually nonexistent. Babies do not distinguish themselves as separate entities and often mistake their...

The stem cell niche is the dynamic microenvironment where stem cells reside. Inside these niches, the cells may remain undifferentiated, undergo high self-renewal, or become lineage-specific progenitors. Stem cells coexist with other niche cells, such as stromal cells. They also interact closely with the ECM. Cell-cell and cell-matrix communication occur via adhesion molecules or soluble factors that signal the stem cells and determine their fate. Stromal cells also provide survival signals to...

Role-based identities are central to understanding how individuals navigate social environments by adopting distinct self-conceptions aligned with various societal roles. These identities are not fixed traits but are constructed through personal actions and the social feedback individuals receive in context-specific interactions. Each social role, such as student, teacher, or friend, carries a set of expectations and norms that influence how people think, feel, and behave within that...