The Bible calls each of the six events in time that God wished to create a “Day”. These "Days" could have been spaced minutes, hours, days or millions of years apart as we understand time. It could be that once Adam and Eve were created, time as we human beings understand it (the 24-hour clock) began.
As for the Yucca and the moth, maybe those "Days" of creation were shorter periods of time we as human beings understand.
It really isn't very hard to try and coincide the Bible with evolution.
Actually, I wonder why someone would want to harmonize the Bible with a man-made theory that is largely being abandoned as being unworkable.
I assume you are referring to the lesson titled, "How Long is a Day?" since that is the only page that refers to the problem of fertilization of the Yucca plant.
Your approach is amusing. God could have created the world in any length of time He wanted. A day could have been some other unit of measure. Time could have been measured differently before Adam and Eve. Of course, I could be debating with a rabbit for that matter. The point is that what could have happened does not establish what happened. It is not evidence.
What stands against your argument is language. Words express meaning to communicate meaning. Thus, for your theory to stand, it would be necessary to show that variable lengths of time are among the various ways a reader of those words could understand them. "For whatever things were written before were written for our learning" (Romans 15:4).
"So the evening and the morning were the first day" (Genesis 1:5).
"So the evening and the morning were the second day" (Genesis 1:8).
"So the evening and the morning were the third day" (Genesis 1:13)."
"So the evening and the morning were the fourth day" (Genesis 1:19).
"So the evening and the morning were the fifth day" (Genesis 1:23).
"So the evening and the morning were the sixth day" (Genesis 1:31).
"And on the seventh day God ended His work which He had done, and He rested on the seventh day from all His work which He had done. Then God blessed the seventh day and sanctified it, because in it He rested from all His work which God had created and made" (Genesis 2:2-3).
A friend and fellow preacher did an exhaustive study of the word "day" in the entire Bible to attempt to see if its use in Genesis 1 and 2 could be construed to mean a long age. The study can be found at The Definition of "Day" in Creation Accounts. There are thirteen cases where an ordinal number is connected to the word "day," that is, where there is a sequence of first day, second day, etc. The passages are: Genesis 1:8-2:3; Exodus 14:9,10; Numbers 6:9,10; Numbers 7:12-78; Numbers 28:16,17; Numbers 29:17-35; Joshua 6:14,15; Judges 19:5-8; Judges 20:22-30; Esther 9:17; Esther 9:18; Esther 9:21; Ezekiel 45:21-25. The passage in Genesis 1-2 is what we are discussing, but ignoring it and looking at all the others, every single case refers to a fixed set of literal 24-hour days. Outside of a very few passages in the Prophets where prophetic writing uses the word "day" symbolically, every usage of the word day refers to a 24-hour period.
It almost seems as if God expected people to question the length of the day because notice the use of the phrase "evening and morning." One evening plus one morning gives you one day. Such wording conveys no other time period than a 24-hour day. If a day was a million years, then the world would have experienced 500,000 years of darkness followed by 500,000 years of light. But such a world would not sustain life. Hence, language and logic state your conclusion to be false.
Then we other statements concerning the creation.
"Remember the Sabbath day, to keep it holy. Six days you shall labor and do all your work, but the seventh day is the Sabbath of the LORD your God. In it you shall do no work: you, nor your son, nor your daughter, nor your male servant, nor your female servant, nor your cattle, nor your stranger who is within your gates. For in six days the LORD made the heavens and the earth, the sea, and all that is in them, and rested the seventh day. Therefore the LORD blessed the Sabbath day and hallowed it" (Exodus 20:8-11).
"Therefore the children of Israel shall keep the Sabbath, to observe the Sabbath throughout their generations as a perpetual covenant. 'It is a sign between Me and the children of Israel forever; for in six days the LORD made the heavens and the earth, and on the seventh day He rested and was refreshed.'" (Exodus 31:16-17).
The Israelites were given a law to rest every seventh day because God made the world in six days and rested on the seventh. Do we conclude that Israelites haven't had a break yet because six million years haven't passed since this law was given? No? Well, why not, if the meaning of the word "day" is as fluid as you argue? The obvious answer is that word is not that fluid and the Israelites knew exactly what was meant -- six days of work, followed by one day of rest, which they knew to be exactly how God operated when He made the world.