Convergent Evolution

Ichthyosaur and Dolphin

No this article has not escaped from my Maths & Science section, it is actually about data matters. But first of all, channeling Jennifer Aniston [1], “here comes the Science bit – concentrate”.

Shared Shapes

The Theory of Common Descent holds that any two organisms, extant or extinct, will have a common ancestor if you roll the clock back far enough. For example, each of fish, amphibians, reptiles and mammals had a common ancestor over 500 million years ago. As shown below, the current organism which is most like this common ancestor is the Lancelet [2].

Chordate Common Ancestor

To bring things closer to home, each of the Great Apes (Orangutans, Gorillas, Chimpanzees, Bonobos and Humans) had a common ancestor around 13 million years ago.

Great Apes Common Ancestor

So far so simple. As one would expect, animals sharing a recent common ancestor would share many attributes with both it and each other.

Convergent Evolution refers to something else. It describes where two organisms independently evolve very similar attributes that were not features of their most recent common ancestor. Thus these features are not inherited, instead evolutionary pressure has led to the same attributes developing twice. An example is probably simpler to understand.

The image at the start of this article is of an Ichthyosaur (top) and Dolphin. It is striking how similar their body shapes are. They also share other characteristics such as live birth of young, tail first. The last Ichthyosaur died around 66 million years ago alongside many other archosaurs, notably the Dinosaurs [3]. Dolphins are happily still with us, but the first toothed whale (not a Dolphin, but probably an ancestor of them) appeared around 30 million years ago. The ancestors of the modern Bottlenose Dolphins appeared a mere 5 million years ago. Thus there is tremendous gap of time between the last Ichthyosaur and the proto-Dolphins. Ichthyosaurs are reptiles, they were covered in small scales [4]. Dolphins are mammals and covered in skin not massively different to our own. The most recent common ancestor of Ichthyosaurs and Dolphins probably lived around quarter of a billion years ago and looked like neither of them. So the shape and other attributes of Ichthyosaurs do not come from a common ancestor, they have developed independently (and millions of years apart) as adaptations to similar lifestyles as marine hunters. This is the essence of Convergent Evolution.

That was the Science, here comes the Technology…

A Brief Hydrology of Data Lakes

From 2000 to 2015, I had some success [5] with designing and implementing Data Warehouse architectures much like the following:

Data Warehouse Architecture (click to view larger version in a new window)

As a lot of my work then was in Insurance or related fields, the Analytical Repositories tended to be Actuarial Databases and / or Exposure Management Databases, developed in collaboration with such teams. Even back then, these were used for activities such as Analytics, Dashboards, Statistical Modelling, Data Mining and Advanced Visualisation.

Overlapping with the above, from around 2012, I began to get involved in also designing and implementing Big Data Architectures; initially for narrow purposes and later Data Lakes spanning entire enterprises. Of course some architectures featured both paradigms as well.

One of the early promises of a Data Lake approach was that – once all relevant data had been ingested – this would be directly leveraged by Data Scientists to derive insight.

Over time, it became clear that it would be useful to also have some merged / conformed and cleansed data structures in the Data Lake. Once the output of Data Science began to be used to support business decisions, a need arose to consider how it could be audited and both data privacy and information security considerations also came to the fore.

Next, rather than just being the province of Data Scientists, there were moves to use Data Lakes to support general Data Discovery and even business Reporting and Analytics as well. This required additional investments in metadata.

The types of issues with Data Lake adoption that I highlighted in Draining the Swamp earlier this year also led to the advent of techniques such as Data Curation [6]. In parallel, concerns about expensive Data Science resource spending 80% of their time in Data Wrangling [7] led to the creation of a new role, that of Data Engineer. These people take on much of the heavy lifting of consolidating, fixing and enriching datasets, allowing the Data Scientists to focus on Statistical Analysis, Data Mining and Machine Learning.

Big Data Architecture (click to view larger version in a new window)

All of which leads to a modified Big Data / Data Lake architecture, embodying people and processes as well as technology and looking something like the exhibit above.

This is where the observant reader will see the concept of Convergent Evolution playing out in the data arena as well as the Natural World.

In Closing

Convergent Evolution of Data Architectures

Lest it be thought that I am saying that Data Warehouses belong to a bygone era, it is probably worth noting that the archosaurs, Ichthyosaurs included, dominated the Earth for orders of magnitude longer that the mammals and were only dethroned by an asymmetric external shock, not any flaw their own finely honed characteristics.

Also, to be crystal clear, much as while there are similarities between Ichthyosaurs and Dolphins there are also clear differences, the same applies to Data Warehouse and Data Lake architectures. When you get into the details, differences between Data Lakes and Data Warehouses do emerge; there are capabilities that each has that are not features of the other. What is undoubtedly true however is that the same procedural and operational considerations that played a part in making some Warehouses seem unwieldy and unresponsive are also beginning to have the same impact on Data Lakes.

If you are in the business of turning raw data into actionable information, then there are inevitably considerations that will apply to any technological solution. The key lesson is that shape of your architecture is going to be pretty similar, regardless of the technical underpinnings.


The two of us are constantly mistaken for one another.
To be clear the common ancestor was not a Lancelet, rather Lancelets sit on the branch closest to this common ancestor.
Ichthyosaurs are not Dinosaurs, but a different branch of ancient reptiles.
This is actually a matter of debate in paleontological circles, but recent evidence suggests small scales.

A term that is unaccountably missing from The Data & Analytics Dictionary – something to add to the next release. UPDATE: Now remedied here.
Ditto. UPDATE: Now remedied here


From:, home of The Data and Analytics Dictionary, The Anatomy of a Data Function and A Brief History of Databases


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