Answer:
Here are the eras and periods when each of the mentioned events first appeared:
- **First prokaryotic cells**
- Era: Archean Eon
- Period: No specific geological period, as they appeared around 3.8 billion years ago.
- **First colonization of land**
- Era: Paleozoic Era
- Period: Silurian Period (around 430 million years ago)
- **First amphibians**
- Era: Paleozoic Era
- Period: Devonian Period (around 370 million years ago)
- **First eukaryotic cells**
- Era: Proterozoic Eon
- Period: No specific geological period, but they are thought to have appeared around 2 billion years ago.
- **Earliest flowering plants**
- Era: Mesozoic Era
- Period: Early Cretaceous Period (around 130 million years ago)
- **Earliest dinosaurs**
- Era: Mesozoic Era
- Period: Triassic Period (around 230 million years ago)
