# TimeTree HD > Public knowledge-base for evolutionary timescale and organism divergence times. (iPhone/iPad app by Arizona and Penn State Universities.) - Source: https://appshunter.io/ios/app/timetree-hd/id468820058 (this page in markdown: same URL + `.md`) - Developer: [Arizona and Penn State Universities](https://appshunter.io/developer/372842503) - Category: Education, Reference - Price: Free - Rating: 1.00/5 from 1 App Store ratings · 8 written reviews indexed - Age rating: 4+ - Requires: iOS 8.0 · 66 MB - Languages: American English - Released: 2011-10-13 - Data updated: 2026-06-05 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/timetree-hd/id468820058/reviews.md ## What is TimeTree HD? TimeTree 4 is a public knowledge-base for information on the evolutionary timescale of life. This application allows easy exploration of the thousands of divergence times among organisms in the scientific literature. A tree-based (hierarchical) system is used to identify all published molecular time estimates bearing on the divergence of two chosen organisms, such as species, compute summary statistics, and present the results. Names of two taxa to be compared are entered in the search window and the results are presented on a set of self-explanatory tabs. TimeTree 4 contains data from 2,274 studies including 50,632 species. We will be adding more data in the future as it comes in from researchers. TimeTree 4 requires iOS 8.0 or newer. The TimeTree project is jointly directed by Blair Hedges (Center for Biodiversity, Temple University) and Sudhir Kumar (Institute for Genomics and Evolutionary Medicine, Temple University). This project has been supported, in part, by grants from the National Science Foundation, National Institutes of Health, NASA Astrobiology Institute, and Science Foundation of Arizona. ## Key features - Explore evolutionary timescale - Thousands of divergence times - Tree-based hierarchical system - Search for organism comparisons - Compute summary statistics - Data from 2,274 studies ## Recent user reviews (8 of 8) All indexed reviews: https://appshunter.io/ios/app/timetree-hd/id468820058/reviews.md ### 1/5 — Not working :( *2015-02-25* It's not working... Sorry ### 5/5 — Amazing *2013-03-03* wonderful app that reaches further and further with citations and data. Comes from a world renown evolution genetics program. All I can say is thanks ### 1/5 — AFP *2013-02-06* Deleted this item. Doesn't work! Error 104 and it stops! ### 5/5 — Great *2013-01-29* Great little app, interface took a few minutes to get used to. Like that it has links to sources. Can't imagine this app will be popular with nutty creationists mind you. :-) ### 5/5 — Awesome *2012-12-17* This app is so great! Will be using for school and citing in papers. Links follow you to NCBI web page and the original study. Wow! Recommend. ### 1/5 — Does not work. *2012-10-18* I love the idea of this app, but it does not work. Every time I search for an animal it tells me there is a server error. ### 5/5 — Great! *2012-07-18* Functions without issue. Data are accurate with references linked to NCBI summaries. Great reference and useful for illustrating evolutionary relationships in class. Bravo! ### 4/5 — Please correct my previous review *2011-11-17* I just submitted a generally favorable review of this APP, but complained that it needed a version specifically adapted to the iPad/iPad2. I then went back to the APP store and realized that there are two separate versions, one for the iTouch/iPhone, and a second version for the iPad. The iPad version uses full screen, but only displays in portrait mode, not landscape. Very useful program. ## Frequently asked questions about TimeTree HD ### What is TimeTree HD? TimeTree HD is a public knowledge-base for information on the evolutionary timescale of life. It allows users to explore divergence times among thousands of organisms based on scientific literature. ### How does TimeTree HD present data? The application uses a tree-based, hierarchical system to identify published molecular time estimates for the divergence of two chosen organisms. Results are presented on self-explanatory tabs. ### What kind of data does TimeTree HD contain? TimeTree HD contains data from 2,274 studies, including information on 50,632 species. The developers plan to add more data in the future. ### What are the system requirements for TimeTree HD? TimeTree HD requires iOS 8.0 or newer and is supported on iPads. ### Who directs the TimeTree project? The TimeTree project is jointly directed by Blair Hedges from Temple University's Center for Biodiversity and Sudhir Kumar from Temple University's Institute for Genomics and Evolutionary Medicine. ### How often is TimeTree HD updated? The latest version of TimeTree HD is 4.0, which was last updated on August 3, 2015. This indicates infrequent updates. ### Is TimeTree HD free to use? Yes, TimeTree HD is available for free and does not feature in-app purchases or advertisements. ### What is the user sentiment for TimeTree HD? Based on the provided data, TimeTree HD has a rating of 1.0 stars from 1 rating, suggesting very limited user feedback and potentially a negative initial impression. ## Version history (last 3 releases) ### 4.0 — 2015-08-03 This app has been updated by Apple to display the Apple Watch app icon. New universal app for iPad and iPhone. New divergence times from over 2000 studies. Numerous bug fixes and server updates. ### 3.1 — 2011-12-15 Calculations have been improved so that the times from any one study do not dominate the overall results. ### 3.0 — 2011-10-10 No release notes. ## Apps similar to TimeTree HD | App | Rating | Price | Category | | --- | --- | --- | --- | | [Genetics and Molecular Biology](https://appshunter.io/ios/app/genetics-and-molecular-biology/id1209436006) | — | $0.99 | Education | | [Phylogenetic Tree Draw](https://appshunter.io/ios/app/phylogenetic-tree-draw/id6443900345) | — | $4.99 | Education | | [CloudLabs Life Classification](https://appshunter.io/ios/app/cloudlabs-life-classification/id1636554237) | — | Free | Education | | [Certified Sommelier Part II MC](https://appshunter.io/ios/app/certified-sommelier-part-ii-mc/id1412366845) | 2.3 (3) | $9.99 | Education | | [Somos Ubuntu](https://appshunter.io/ios/app/somos-ubuntu/id6738665023) | — | Free | Education | | [Human Eye Receptors](https://appshunter.io/ios/app/human-eye-receptors/id1011680827) | — | $0.99 | Education | ## More apps by Arizona and Penn State Universities - [TimeTree](https://appshunter.io/ios/app/timetree/id372842500) All apps by Arizona and Penn State Universities: https://appshunter.io/developer/372842503 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-05.*