How does descent with modification relate to evolution?

A creature doesn't simply transform into a different species. Rather, adaptations happen gradually over many generations, one tiny step at a time, toward the other animal. There are numerous animals that exist in between point A and point B. Huge changes are composed of countless tiny ones. As an illustration, when we state that a dog "evolved" from a wolf:

A wolf is a big, hairy, mean animal. The next step is to make them friendlier. The next step is to make them smaller. The next step is to make them friendlier, smaller, and less hairy. Each step is a wolf, just modified. Each descendant is only a few changes away from the parent. Over a very long time, some of these changes are favored over others. Some of these changes come with gene linkage. Other things, like floppy ears or pushed in noses, occur. Some adaptations are environmental.

The wolf did not just wake up in Mexico, lose its fur, grow tiny, and sit in a designer purse. Rather, it took many steps and many generations of adaptation to create the chihuahua, a tiny, bald, shivery animal that is unable to mate and produce a wolf.

Descent with modification is a central concept in evolution proposed by Charles Darwin. It suggests that species evolve over time through gradual changes in their inherited traits, leading to the formation of new species. This process occurs as individuals with advantageous traits are more likely to survive and reproduce, passing on those traits to their offspring. Over generations, these accumulated modifications can result in significant differences between populations, ultimately leading to the emergence of new species.