Final answer:
The IUCN began its conservation status assessments in 1963 with the 'Red List' process, which has since evolved to use quantitative criteria to categorize species based on the risk of extinction.
Step-by-step explanation:
The IUCN began assessments of conservation status in 1963 with the 'Red List' process. This initiative has evolved significantly since its inception in the 1960s. Initially, it was a simple list for qualitative threat assessments for selected species, but over the last two decades, the process has undergone substantial revisions. The assessments have become more quantitative and are now based on extinction risk and criteria for different threat categories, which consider factors such as population size, range, and degree of population decline.
The IUCN Red List is a critical scientific resource in global conservation efforts and helps to inform environmental impact assessments, conservation planning, and the allocation of resources to safeguard biodiversity. It also guides the identification of key biodiversity areas, prioritizing sites that require urgent conservation action.