Asset Details
Do you wish to reserve the book?
Lost world of complex life and the late rise of the eukaryotic crown
Hey, we have placed the reservation for you!
By the way, why not check out events that you can attend while you pick your title.
Oops! Something went wrong.
Looks like we were not able to place the reservation. Kindly try again later.
Are you sure you want to remove the book from the shelf?
Lost world of complex life and the late rise of the eukaryotic crown
Do you wish to request the book?
Lost world of complex life and the late rise of the eukaryotic crown
Please be aware that the book you have requested cannot be checked out. If you would like to checkout this book, you can reserve another copy
We have requested the book for you!
Your request is successful and it will be processed during the Library working hours. Please check the status of your request in My Requests.
Oops! Something went wrong.
Looks like we were not able to place your request. Kindly try again later.
Journal Article
Lost world of complex life and the late rise of the eukaryotic crown
2023
Overview
Eukaryotic life appears to have flourished surprisingly late in the history of our planet. This view is based on the low diversity of diagnostic eukaryotic fossils in marine sediments of mid-Proterozoic age (around 1,600 to 800 million years ago) and an absence of steranes, the molecular fossils of eukaryotic membrane sterols
1
,
2
. This scarcity of eukaryotic remains is difficult to reconcile with molecular clocks that suggest that the last eukaryotic common ancestor (LECA) had already emerged between around 1,200 and more than 1,800 million years ago. LECA, in turn, must have been preceded by stem-group eukaryotic forms by several hundred million years
3
. Here we report the discovery of abundant protosteroids in sedimentary rocks of mid-Proterozoic age. These primordial compounds had previously remained unnoticed because their structures represent early intermediates of the modern sterol biosynthetic pathway, as predicted by Konrad Bloch
4
. The protosteroids reveal an ecologically prominent ‘protosterol biota’ that was widespread and abundant in aquatic environments from at least 1,640 to around 800 million years ago and that probably comprised ancient protosterol-producing bacteria and deep-branching stem-group eukaryotes. Modern eukaryotes started to appear in the Tonian period (1,000 to 720 million years ago), fuelled by the proliferation of red algae (rhodophytes) by around 800 million years ago. This ‘Tonian transformation’ emerges as one of the most profound ecological turning points in the Earth’s history.
Analysis of sedimentary rocks from the mid-Proterozoic interval reveals traces of protosteroids, suggesting the widespread presence of stem-group eukaryotes that predated and co-existed with the crown-group ancestors of modern eukaryotes.
Publisher
Nature Publishing Group UK,Nature Publishing Group
Subject
/ Algae
/ Aquatic Organisms - chemistry
/ Aquatic Organisms - classification
/ Aquatic Organisms - metabolism
/ Bacteria
/ Biota
/ Clocks
/ Eukaryotic Cells - chemistry
/ Eukaryotic Cells - classification
/ Eukaryotic Cells - metabolism
/ Fossils
/ Geologic Sediments - chemistry
/ Geology
/ Humanities and Social Sciences
/ Science
/ Steroids
/ Sterols
/ Sterols - isolation & purification
/ Trends
