# Diversity on land vs Diversity in oceans **URL:** \ **Category:** Factual Questions\ **Created:** [September 3, 2016, 11:49am UTC](https://boards.straightdope.com/t/diversity-on-land-vs-diversity-in-oceans/764863 "2016-09-03T11:49:15Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Nansbread1](https://avatars.discourse-cdn.com/v4/letter/n/6a8cbe/32.png) [@Nansbread1](https://boards.straightdope.com/u/Nansbread1)\ **Post date:** [September 3, 2016, 11:49am UTC](https://boards.straightdope.com/t/diversity-on-land-vs-diversity-in-oceans/764863/1 "2016-09-03T11:49:15Z")
What is the dope on this? Are there more diverse creatures on land ( man, all types of vertebrates, invertebrates, birds, plants, trees etc etc) or in the sea (fishes, vertebrates, in vertebrates, plants etc etc) Not in total numbers but variety (genus,species etc). Who wins. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [September 3, 2016, 12:00pm UTC](https://boards.straightdope.com/t/diversity-on-land-vs-diversity-in-oceans/764863/2 "2016-09-03T12:00:03Z")
There is more diversity on land. A 2011 survey found 6.5 million species on land compared to 2.2 million species in oceans. There’s also this: > [@](#): > > Firstly: there are many more different environments on land than in the oceans. This will lead to increased diversity, and subsequently more species. > > To a lesser degree/no evidence to back this up :): > > a) insects make up a good portion of total number of species, but are virtually absent from marine environments > > b) we explore terrestrial environments a lot more easily than we do ocean environments, which will bias the ratio somewhat. From here: [http://www.askabiologist.org.uk/answers/viewtopic.php?id=2874](http://www.askabiologist.org.uk/answers/viewtopic.php?id=2874) ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [September 3, 2016, 4:11pm UTC](https://boards.straightdope.com/t/diversity-on-land-vs-diversity-in-oceans/764863/3 "2016-09-03T16:11:05Z")
What’s interesting is that while the total animal species diversity is quite landwards skewed, it isn’t that way for chordates or molluscs, where it’s about a 50/50 split. Arthropods greatly skew the picture, and that’s down to the insects. Which is understandable if you consider ocean continuity vs the possibility for island effects in terrestrial habitats. Also the greater energy budget for terrestrial life. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [September 3, 2016, 4:13pm UTC](https://boards.straightdope.com/t/diversity-on-land-vs-diversity-in-oceans/764863/4 "2016-09-03T16:13:26Z")
Also the diversity scale will be different depending on what level we’re measuring. Species? Or phyla? ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [September 3, 2016, 4:20pm UTC](https://boards.straightdope.com/t/diversity-on-land-vs-diversity-in-oceans/764863/5 "2016-09-03T16:20:41Z")
_How Many Species Are There on Earth and in the Ocean?_ Mora et al, 2011 > [@](#): > > Here we show that the higher taxonomic classification of species (i.e., the assignment of species to phylum, class, order, family, and genus) follows a consistent and predictable pattern from which the total number of species in a taxonomic group can be estimated. This approach was validated against well-known taxa, and when applied to all domains of life, it predicts ∼8.7 million (±1.3 million SE) eukaryotic species globally, of which ∼2.2 million (±0.18 million SE) are marine. In spite of 250 years of taxonomic classification and over 1.2 million species already catalogued in a central database, our results suggest that some 86% of existing species on Earth and 91% of species in the ocean still await description. > **[How Many Species Are There on Earth and in the Ocean?](https://journals.plos.org/plosbiology/article?id=10.1371%2Fjournal.pbio.1001127)** > > Author Summary Knowing the number of species on Earth is one of the most basic yet elusive questions in science. Unfortunately, obtaining an accurate number is constrained by the fact that most species remain to be described and because indirect... ETA: just realized this is obviously the same study that eng’\_comp\_geek mentioned above ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [September 3, 2016, 6:45pm UTC](https://boards.straightdope.com/t/diversity-on-land-vs-diversity-in-oceans/764863/6 "2016-09-03T18:45:21Z")
My understanding is that there is only a 2 billion year window for life to exist on land. The window opened about a billion years ago, and will close about a billion years from now. It has something to do with the sun, but I forget what. Consider that life is 4 billion years old, and that the first land based life probably happened about 500 million years ago, water based life has a major head start. You also have to consider that the vast majority of life on earth consists of single celled organisms. We are only beginning to be able to determine the genetic diversity of single celled life. A ml of water has something like several hundred million bacteriophages, viruses, bacteria, etc. so there is going to be a lot of biodiversity in there. Far larger than you will find among multi-cellular life. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [September 3, 2016, 10:27pm UTC](https://boards.straightdope.com/t/diversity-on-land-vs-diversity-in-oceans/764863/7 "2016-09-03T22:27:00Z")
> [@Nansbread1](#): > > What is the dope on this? Are there more diverse creatures on land ( man, all types of vertebrates, invertebrates, birds, plants, trees etc etc) or in the sea (fishes, vertebrates, in vertebrates, plants etc etc) You forgot one: in the air. And that wins, because of insects. Though I guess you could claim that they belong to one of the others, since most don’t fly continuously – most alight on land, and some on water.