a.k.a. evolution. It’s not all that scary or controversial until someone with a stake in your ignorance makes it that way.
From Understanding Evolution: “Unfortunately, many people have persistent misconceptions about evolution. Some are simple misunderstandings—ideas that develop in the course of learning about evolution, possibly from school experiences and/or the media. Other misconceptions may stem from purposeful attempts to misrepresent evolution and undermine the public’s understanding of this topic..”.
or have a look at Berkley’s webpage here to understand some basic biology:
Also, a very simplified explanation of how diversity and adaptation work: