the earliest known life form were single celled organisms which roamed the earth they appeared around two billion years ago
Answer:
The Earth formed about 4.5 billion years ago. 700 million years later (3.8 to 3.5 billion years age) life started.
Pre-Cambrian. It's when bacteria first came about.
Mammals first appear in the fossil record of the Mesozoic Era.
Cycads first appeared in the fossil record during the early Permian period, around 280 million years ago. They are often referred to as "living fossils" due to their ancient lineage and resemblance to plants from that era.
Pre-Cambrian. It's when bacteria first came about.
The first dinosaurs lived in the beginning of the Mesozoic Era (or the Age of Reptiles). Birds were amazingly discovered to be dinosaurs so dinosaurs were also alive in the Cenozoic (that's our time-the Age of Mammals) to today.
probably mesozoic era
Vertebrates first appeared during the Paleozoic era.
the cenozoic era
Pre-Cambrian. It's when bacteria first came about.
Actually they were from the Pennsylvanian Period and the Paleozoic Era...
Silurian
The Cenozoic era at about 65 million years ago. The Paleogene period.
9500 BC. When the switch between the Paleolithic Era to the Neolithic Era began.
Reptiles first appeared during the Paleozoic Era, specifically the Carboniferous System of the Paleozoic Era. That was about 320 million years ago.
before time even started when mesopotamians were alive.
Early man first appeared in the Cenozoic Era, specifically during the Quaternary Period. This era began around 2.6 million years ago and continues to the present day.
Mammals first appear in the fossil record of the Mesozoic Era.