Here's a breakdown of why this is the case:
* Evolutionary History: All life on Earth is connected through a shared evolutionary history. This means that every species has a lineage that can be traced back to a common ancestor.
* Shared Traits: Species that share a recent common ancestor will have more similar characteristics (both physical and genetic) than species that share a more distant common ancestor. This is because they've had less time to evolve independently and accumulate differences.
* Genetic Similarity: The closer the relationship between two species, the more similar their DNA will be. This is the most direct way to determine how closely related two species are.
Examples:
* Humans and chimpanzees: Share a very recent common ancestor and are incredibly similar genetically.
* Dogs and wolves: Also share a recent ancestor, and though they have some physical differences, their genetic similarities are very high.
* Humans and bacteria: Share a distant common ancestor and have vastly different genetic makeup.
It's important to note that "closely related" is a relative term. Two species might be considered closely related compared to others, but still have a significant evolutionary distance between them.
