1. Many plants have an interesting defense system against insects. When they are damaged they release feromones attracting predatory insects, like wasps.
2. Evolution of human brain was extremely rapid and involved multiple mutations in multiple genes. It is estimated that for the last 300,000 years the average rate of fixation of mutations (related to brain function) in human population was 1 in 1000-2000 years. And it is still evolving. For example, at least one mutation appeared ~30.000 years ago and now is present in ~40% of all humans. This is very recent history, considering the fact that our recorded history starts about 6000 years ago.
3. Some predators have a mechanism to judge the aminoacid content of their stomachs in ~20 minutes (this is VERY fast). If the amount of protein is not high enough, they puke it out.