AP BIOLOGY

Detailed explanation-1: -Similarities and differences among biological molecules (e.g., in the DNA sequence of genes) can be used to determine species’ relatedness. Biogeographical patterns provide clues about how species, both alive and extinct, are related to each other.

Detailed explanation-2: -However, now scientists can also analyze DNA to discover how closely organisms are related. Every living creature has DNA, which has a lot of inherited information about how the body builds itself. Scientists can compare the DNA of two organisms; the more similar the DNA, the more closely related the organisms.

Detailed explanation-3: -The DNA of two closely related organisms will be more similar than the DNA of two distantly related organisms. Based on the current research findings, all organisms on earth are evolved from a common ancestor, which is assumed to be a single-celled organism and present at 3.5 billion years ago (BYA).

Detailed explanation-4: -In a phylogenetic tree, the relatedness of two species has a very specific meaning. Two species are more related if they have a more recent common ancestor, and less related if they have a less recent common ancestor.