Quirks & Quarks

How far back, evolutionarily speaking, do circadian rhythms go in animals?

Circadian rhythms are part of the DNA of every complex organism and have been around for billions of years.

Circadian rhythms are part of the DNA of every complex organism and have been around for billions of years

Marla in full circadian rhythm demonstration mode (Amanda Buckiewicz)

This week's question comes to us from Mike Holmes in Indianapolis, Indiana. He asks:

How far back, evolutionarily speaking, do circadian rhythms go in animals?

Tami Martino, a professor in biomedical sciences at the University of Guelph reminds us that circadian rhythms are our body's way of keeping track of the day and night. They very likely evolved because being in sync with the day-night environment provides a selective advantage. 

Ancient single celled organisms called prokaryotes had three circadian genes, the oldest of which is thought to have appeared 3.8 billion years ago. All modern plants and animals have circadian rhythm genes. 

 

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