Where does invasion collide?

In ecology, an invasion is the process by which a species carried beyond its natural range establishes a self-sustaining population and spreads through a new region, often to the detriment of the resident species. Blackburn and colleagues' 2011 A proposed unified framework for biological invasions set out the stages a non-native species must pass through, from transport and introduction to establishment and spread, with a barrier to cross at each step. The referent is a living population expanding across a landscape over years and decades, not cancer cells crossing a tissue boundary, an army crossing a national border, or a stranger prying into a private life.[1]

Unit

One non-native species establishing and spreading in a new range

Recovery means

Eradication or control may reverse it if attempted before the population spreads widely

Measured by

Tracked by range size, population growth, and impact on native species, and placed along the introduction-to-spread framework

In cancer cell biology, invasion is the penetration of malignant cells through the basement membrane and into the surrounding tissue, the step that marks a growth as malignant rather than benign and that usually precedes spread to distant organs. Friedl and Wolf's 2003 Tumour-cell invasion and migration reviewed how cancer cells break down the surrounding matrix, change shape, and move through tissue. The referent is a microscopic breach of a tissue boundary by rogue cells inside a single body, not a species colonising a region, an armed force seizing land, or an intrusion into a person's private affairs.[2]

Unit

Malignant cells crossing the basement membrane into nearby tissue

Recovery means

Not applicable; invasion is a step toward malignancy that surgery or therapy aims to halt

Measured by

Graded on tissue sections by depth of penetration and margin involvement, and studied in assays of matrix degradation and cell migration

In law, invasion of privacy is the wrong of intruding upon a person's seclusion or exposing their private affairs without consent. Warren and Brandeis's 1890 The Right to Privacy argued that the common law should protect an individual's right to be let alone, a foundation later developed into the recognised tort of intrusion upon seclusion. The referent is a legal injury to one person's private life, remedied by a court, not a biological population spreading, cancer cells crossing a membrane, or an army entering a country.[3]

Unit

One wrongful intrusion into a person's private life

Recovery means

Not applicable; the injured person may seek damages or an injunction

Measured by

Established in court by showing an intrusion into a private matter that a reasonable person would find highly offensive