To build accurate phylogenetic trees, scientists use different methods that look at genetic information, physical traits of organisms, and stats. Here’s a breakdown of the main techniques they use:

1. Molecular Data Analysis:

   • Scientists collect genetic information from DNA or RNA.
   • They often look at special markers, like mitochondrial DNA.
   • One example of this is using cytochrome c oxidase I (COI) to tell apart different species. In some cases, it can be over 90% accurate!

2. Morphological Data Comparison:

   • This method compares the physical traits of different species.
   • They document features like bone structure, size, and how they reproduce.
   • In a study of animals with backbones (vertebrates), they looked at over 200 physical traits to find relationships.

3. Computational Algorithms:

   • Scientists apply methods like Maximum Likelihood (ML) and Bayesian Inference (BI) to create trees based on genetic data.
   • For example, ML checks many tree shapes to find the one that fits the data best, often looking at thousands of sequences at once.

4. Statistical Techniques:

   • Techniques like bootstrapping help evaluate how trustworthy the trees are.
   • This involves taking samples from the data, making trees, and seeing how stable they are.
   • A bootstrap value over 70% shows strong support for a certain part of the tree.

5. Software Tools:

   • Programs like MEGA, BEAST, and RAxML are commonly used. They help scientists visualize phylogenetic trees and use complex stats to analyze genetic data.
   • Thanks to better computers, datasets can now include millions of base pairs, making the trees more accurate.

6. Integrative Approaches:

   • Sometimes, scientists mix molecular data, physical traits, and ecological information to get a full picture.
   • These combined methods can offer new insights into how species evolved, and they sometimes use machine learning to improve predictions.

All these techniques come together to create clearer images of how species are related. Phylogenetic trees give scientists a better understanding of the history and variety of life on Earth.