Final answer:
Extinction is the evaluative process causing a species to disappear entirely from Earth. Human activities have drastically increased current extinction rates. Biologists use population size, trends, and habitat conditions to predict potential extinctions.
Step-by-step explanation:
An evaluative process that leads to the disappearance of species or populations is known as extinction. This event occurs when the last individual of a species dies, leading to its complete absence from Earth. Biologists identify potential extinctions by looking for indicators such as small population size, declining numbers, and loss of habitat. Extinctions have been part of Earth's history, with natural rates of species loss. However, contemporary extinction rates are alarmingly high due to human activities such as habitat destruction, introduction of invasive species, and over-harvesting. The current rate of species loss is estimated to be 500-1000 times higher than the natural background rate, with predictions that 10 to 50 percent of species could be lost within the next century, a rate comparable to past mass extinction events, but this time primarily driven by human impact.