26-27... tetrapod and unsaturated fat

This random nut found at the river represents an unsaturated fat(big idea 2#37). This type of hydrocarbon contains many unsaturated fats that can be useful in nurturing the new organism, while animals contain saturated fats. They are considered "healthy fats" becuase they are liquids at room temp and are less likely to cause heart attacks/ strokes as saturated fats.

This is a sandy track from a deer, probably a black-tailed or mule deer because these are most common in the area. Deer are a great example of  tetrapods(bid idea 1 #39), which are four-legged creatures with feet including many mammals, reptiles, and amphibians. It is a vary general and broad term used to classify organisms. The first tetrpod evolved from a fish and migrated to land for unknown reasons.