The field may weaken but doesn't disappear lest we become like Mars.Meh, critters can live through anything.Yeah, but our food, wasn't. No food, no life.
Not over a period of 1000 years. If there were a 1000 year period with no magnetic field most life would be gone.
Many shifts in the planets past, but no evidence of a complete field loss.
Pole Reversal Happens All The (Geologic) Time