Final answer:
Estimates of extinction rates from the fossil record can be used to track species loss, but may underestimate the true rate of extinction, while methods using habitat destruction and species-area curves can overestimate the rates.
Step-by-step explanation:
Calculating extinction rates from the fossil record is a method used to estimate the number of species that have disappeared over a particular time period. Estimates of contemporary extinction rates based on the recorded extinction of species in the past 500 years use data from a large number of observations and measurements, yet they may underestimate the true rate since they do not account for unobserved extinctions or undiscovered species.
An alternative method that examines the rate of habitat destruction and uses species-area curves can be more suitable, especially in instances like the construction of a new dam, where habitat loss is a direct consequence. However, this method is not based on existing data and may overestimate extinction rates.