A graph is illustrated where x-axis is 'Millions of Years Ago' ranges from 500 to 0 in decrement of 50 and y-axis is 'Percent of Genera Becoming Extinct' ranges from 0 to 60 in increment of 10. There are bars of different color used to represent the time when a specific genera become extinct. The generas shown on the graph are:
- Cambrian and Ordovician: Become extinct around 450 million years ago
- Silurian: Become extinct around 400 million years ago
- Devonian: Become extinct between 400 and 350 million years ago
- Carboniferous: Become extinct between 300 and 350 million years ago
- Permian: Become extinct between 350 and 200 million years ago
- Triassic: Become extinct between 250 and 300 million years ago
- Jurassic: Become extinct between 200 and 150 million years ago
- Cretaceous: Become extinct between 150 and 50 million years ago
- Paleogene and Neogene: Become extinct between 50 and 0 million years ago
Few geras extinct age is also marked on the graph and includes:
- Ordovician
- Devonian
- Permian
- Triassic
- Cretaceous.