Question: When did the first mammal appear on earth?
Disambiguated questions and answers: question: Which geological periods did the first mammal appear on earth?
Which geological epoch did the first mammal appear on earth?
When did the first mammal appear on earth (years ago)?
Which geological era did the first mammal appear on earth?
answer: Paleogene and Neogene periods of the Cenozoic era
Late Triassic Epoch
225 million years ago
225 mya
Cenozoic era
question: During which geological periods of the Cenozoic era did the first mammal appear on earth?
During which geological epoch did the first mammal appear on earth according to Kemp?
How long ago did the first mammal appear on earth according to Kemp?
During which geological era did the first mammal appear on earth?
answer: Paleogene and Neogene periods
Late Triassic Epoch
225 million years ago
Cenozoic era
Natural Questions answer: late Carboniferous period (from the Wikipedia article "Evolution of mammals")