Appreciate, through genetic crosses, that science is linked to nature.

It would be hard to imagine a more accurate analogy.  The mechanisms that occur in nature in and of themselves involve science in one of it's purest forms, genetics.  A species must be able to reproduce to ensure it's lineage, otherwise extinction is inevitable.  Genetic crossings is one mechanism in place to observe the bond between science and nature.  From Mendel's observations of purebred characteristics and experimentation of crossing those characteristics we see a small, controlled scientific experimentation of what occurs naturally on a grander scale.  All the examples of traits we observe in nature are the results of the breeding of this trait versus that trait.  The final count is off the charts, in terms of total trait accountability.  There is an old saying, "Don't fool with Mother Nature."  Another way of interpreting that old saying would be Mother Nature has been doing what she has been doing for a very long time.  Some traits that were produced were good for the organisms that inherited them, while others were not.  The ones that were not were summarily dismissed from the great progression of life.