Context: This first list is referred to as the "Class of '67" in The Endangered Species Act at Thirty, Volume 1, which concludes that habitat destruction, the biggest threat to those 78 species, is still the same threat to the currently listed species. It included only vertebrates because the Department of Interior's definition of "fish and wildlife" was limited to vertebrates. However, with time, researchers noticed that the animals on the endangered species list still were not getting enough protection, thus further threatening their extinction. The endangered species program was expanded by the Endangered Species Act of 1969.

Question: What is the nickname given to the first listing of endangered species?
Answer: "Class of '67"

Question: What was concluded to be the biggest threat to the listed species?
Answer: habitat destruction

Question: How was the first listing limited in what species were listed?
Answer: It included only vertebrates

Question: How did being listed initially impact species?
Answer: the animals on the endangered species list still were not getting enough protection, thus further threatening their extinction

Question: How many species are currently listed?
Answer: Unanswerable

Question: What type of animal was not included in Volume 1?
Answer: Unanswerable

Question: What volume was published in 1969?
Answer: Unanswerable

Question: What threat towards species has been neutralized?
Answer: Unanswerable

Question: What is the Endangered Species Act of 1969 referred to as?
Answer: Unanswerable