Molecular Evidence

Molecular Evidence

Did you know you share over 98% of your DNA with a chimpanzee? Or that humans have things in common with bananas and even bacteria? That’s because all living things are connected, and we can see those connections by looking at something super tiny: molecules, especially DNA!

Molecular evidence means using DNA and proteins to determine how living things relate. DNA is like a recipe book that tells your body how to grow, work, and stay alive. Scientists find patterns when comparing the DNA of different living things. Some animals have almost the same “recipes”! That’s how we know they’re related, even if they don’t look alike.

Science and Engineering Practices (SEP): Analyzing and Interpreting Data

Scientists don’t just guess who’s related to whom; they analyze data! They look at DNA sequences (those A, T, C, and G letters in your genes) and compare them between species. The more matches they find, the closer the relationship. You can be like a scientist, too! Try matching DNA patterns to see how animals are connected. It’s like solving a family puzzle using genetic clues.

Activity Ideas:

• Build a Family Tree – Get made-up DNA from “alien animals” and determine who’s most related. Then, draw their family tree based on your clues.
• DNA Matching Game – Create simple DNA sequence cards from different animals. Mix them up and challenge yourself or others to find the most similar pairs. Discuss why some sequences look alike and what that says about the animals’ relationships.

Crosscutting Concept (CCC): Patterns

Molecular evidence is all about patterns in DNA and proteins. By looking for patterns, like how many DNA letters are the same, we can predict how animals are related and who came from the same ancestors.

• Pattern: Chimpanzee DNA is almost the same as human DNA
  What it shows: Humans and chimps are close relatives
• Pattern: All living things use the same four DNA letters: A, T, C, and G
  What it shows: Everything alive shares a common origin
• Pattern: Some proteins barely change between animals
  What it shows: Those animals are part of the same big family

Molecular evidence helps us see how all life is connected. It shows how we’re part of nature’s big family, just like you and your cousins share some of the same features, so do animals, plants, and even microscopic creatures. DNA helps us figure out those relationships, even across millions of years!