Which natural event can occur either over a few weeks or over a few million years?
A standing wave can occur only at specific frequencies that are called natural frequencies.
The probability
There are really no steps in natural selection - just conditions required for it to occur.
What population? Perhaps you mean if there were no variation for natural selection to select from.
Without genetic diversity, natural selection cannot occur
Pangaea
earthquake
The probability that an event will not occur is calculated by subtracting the probability of the event occurring from 1. Given that the probability of the event occurring is 0.2, the probability that it will not occur is 1 - 0.2 = 0.8. Thus, there is an 80% chance that the event will not occur.
The chance that a given event will occur usually expressed between the number 0 will not and 1 the event will occur
Probability is the mathematical chance that an event will occur.
The probability that an event will occur plus the probability that it will not occur equals 1.
Probability of success is a mathematical chance that an event will occur.
About 65.5 million years ago. The Cretaceous and Tertiary are geological time periods either side of this event. The event is significant because there was a large mass extinction event at this time including the extinction of all non avian dinosaurs. Most experts agree that the cause of the extinction was a asteroid impact.
The chance that a given event will occur, usually expressed between the number 0 (will not occur) and 1 (will occur) is called probability.
That defines the odds in favour of the event.
How likely it is for an event to occur.
P(a^~a)==1 P(a&~a)==0 the line above is shorthand notation for an event that has a probability of 1, followed by an event that has a probability of 0. P(event) is an easy way to say the probability of "event". The "^" means "OR", the "~" means "NOT", and the "&" as you are probably familiar means "AND". So puting it together, "P(a^~a)" means the probability that an event "a" occurs OR that event "a" does not occur. So take an event "a", any event, like drawing an 8 of clubs out of a deck of cards. If you draw a random card out of a deck of cards, the probability that you will draw an 8 of clubs OR that you will not draw an 8 of clubs is 1. That means 100%. So when you draw a card you will either draw the 8 of clubs or not draw the 8 of clubs. It seems like an obvious statement to make but its a proof that becomes very important in proving less obvious theories. likewise, the second statement was "P(a&~a)", so the probability that event "a" occurs AND event "a" doesnt occur. Since the event has to either occur or not, it cant occur AND not occur, so the probability is 0.