Featured Research

from universities, journals, and other organizations

Earth history and evolution: Cypress tree distribution reflects the breakup of Pangaea

Date:
May 3, 2012
Source:
Ludwig-Maximilians-Universität München
Summary:
In classical mythology, the cypress tree is associated with death, the underworld and eternity. Indeed, the family to which cypresses belong, is an ancient lineage of conifers, and a new study of their evolution affords a unique insight into a turbulent era in the Earth's history.

In classical mythology, the cypress tree is associated with death, the underworld and eternity. Indeed, the family to which cypresses belong, is an ancient lineage of conifers, and a new study of their evolution affords a unique insight into a turbulent era in Earth's history.

During the geological era known as the Mesozoic, the continental crust was concentrated in a single huge landmass, the supercontinent Pangea. Pangea began to break up about 150 million years ago, and the fragments drifted apart, eventually giving rise to the disposition of continents we know today. The progressive break-up of such a large landmass meant that existing groups of plant and animal species were split apart, and the descendant lineages then evolved in isolation from each other.

Dating divergence with the molecular clock

"Fossils show that the cypress family is a very ancient group of plants," says LMU biologist Professor Susanne Renner, who is also Director of the Munich Botanic Garden. "We therefore suspected that it might be possible to follow their evolutionary history back to the period before the break-up of Pangea, as long as the many episodes of climate change and associated extinctions had not obscured things too much." Renner and her research group therefore set out to reconstruct the cypress family tree, based on the comparison of specific gene sequences from 122 species belonging to 32 genera reflecting the family's worldwide distribution. In order to date divergence events, they applied the concept of the molecular clock.

The idea is based on a simple principle. When two lineages diverge from a common ancestor, each accumulates genetic substitutions independent from the other. To a first approximation, the number of unique substitutions provides a measure of the time that has elapsed since a species diverged from its sister species. By comparing the spectra of genetic changes found in different lineages and calibrating the amount of change with fossils, one can therefore reconstruct a group's history.

Evolutionary dead ends

"Over the past 15 years, these molecular methods, in combination with new fossil finds, have revolutionized the study of biogeography, the branch of biology concerned with understanding the distribution patterns of animal and plant species," says Renner. Some groups have turned out to be surprisingly young in evolutionary terms, others much older than people had assumed.

The new study confirms that cypresses represent a very old plant family. Their origins can be traced back to Pangea, and the evolutionary divergence of the northern and southern subfamilies of cypresses actually reflects the break-up of Pangea about 153 million years ago. As fragmentation progressed and ancestral lineages were separated from each other, new lineages were established and followed separate evolutionary trajectories. The Cupressaceae is the first plant family whose evolutionary history gives us such a detailed picture of the break-up of a supercontinent.


Story Source:

The above story is based on materials provided by Ludwig-Maximilians-Universität München. Note: Materials may be edited for content and length.


Journal Reference:

  1. K. Mao, R. I. Milne, L. Zhang, Y. Peng, J. Liu, P. Thomas, R. R. Mill, S. S. Renner. Distribution of living Cupressaceae reflects the breakup of Pangea. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1114319109

Cite This Page:

Ludwig-Maximilians-Universität München. "Earth history and evolution: Cypress tree distribution reflects the breakup of Pangaea." ScienceDaily. ScienceDaily, 3 May 2012. <www.sciencedaily.com/releases/2012/05/120503120116.htm>.
Ludwig-Maximilians-Universität München. (2012, May 3). Earth history and evolution: Cypress tree distribution reflects the breakup of Pangaea. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2012/05/120503120116.htm
Ludwig-Maximilians-Universität München. "Earth history and evolution: Cypress tree distribution reflects the breakup of Pangaea." ScienceDaily. www.sciencedaily.com/releases/2012/05/120503120116.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) — Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) — Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) — At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) — The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins