Is to choose seven out of those 45.

There are C45(7) species

A ***C49(7)

So the probability is1-[c45 (7)]/[c49 (7)] =1-(45 * 44 * 43 * 42 * 41* 40 * 39)/(49 * 48 * 47 *.

= 1-7995/ 15 134

= 7139/15134 is about 0.47.