Explain how studying the DNA of different types of organisms provides evidence that all life on Earth is related.

1. DNA Basics: DNA, or deoxyribonucleic acid, is the genetic material that carries the instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses. It is composed of four types of nucleotides: adenine (A), cytosine (C), guanine (G), and thymine (T). The specific sequence of these nucleotides is what determines an organism's traits.

2. DNA Sequencing: Scientists can study the DNA of different organisms by sequencing it, or determining the exact order of the nucleotides. This allows them to compare the DNA sequences of different organisms.

3. Common DNA Sequences: If two organisms have similar DNA sequences, it suggests that they share a common ancestor. This is because the DNA sequence of an organism is passed down from its parents, with only small changes occurring each generation. Over time, these changes can accumulate, leading to differences in the DNA sequences of different species. However, the basic structure and many sequences remain the same, indicating a common origin.

4. Universal Genetic Code: All organisms use the same genetic code to translate the information in DNA into proteins, the building blocks of life. This suggests that all life on Earth evolved from a common ancestor that used this genetic code.

5. Phylogenetic Trees: By comparing the DNA sequences of different organisms, scientists can construct phylogenetic trees, which show the evolutionary relationships between organisms. The more similar the DNA sequences of two organisms, the more closely related they are likely to be.

6. Fossil Record and DNA: The fossil record provides physical evidence of evolution, showing how organisms have changed over time. DNA provides molecular evidence of these changes, allowing scientists to trace the evolutionary history of organisms and providing further evidence that all life on Earth is related.

In conclusion, studying the DNA of different organisms provides evidence that all life on Earth is related by showing that all organisms use the same genetic code, have similar DNA sequences, and can be placed on a phylogenetic tree that shows their evolutionary relationships.