[SPOILER, but so is the stuff above this reply!]

Have you read the puzzle guide? I think you need to build the dam first so you can have crops growing to support your villagers. There is a link to the puzzle guide in my signature below.

Also, doing what Rosemary suggests (keep game paused and search for mushrooms) can theoretically provide your village with an infinite amount of food.

It goes against logic that mushrooms can grow when everything else on the island is frozen in time. But not only can mushrooms appear, I believe collectibles can appear while the game is paused, and if you pick up a collectible of one you already have it is worth tech points.

It is a shame you do not have a dozen children. When you pause the game and put more than 4 kids on an item then unpause the game, you harvest multiple copies of that item. For some items that are worth several thousand tech points, you can really rack up the points. I recall collecting over 20,000 tech points at once by putting 10 kids on a rare collectible.