by Steven Newton, Public Information Project Director

The age of the Earth is 4.54 billion years (Ga or Gyr), a number which geologists have determined by several independent methods. Because of the recycling of crustal rocks by plate tectonics, no direct material from the earliest Earth still exists. However, geologists are able to analyze meteorites and lunar rocks returned by the Apollo missions.

Methods

Reports of the National Center for Science Education

Title: 

The De-riving Force of Cladogenesis

Author(s): 

Andrew J Petto
University of the Arts

Year: 

1999

Date: 

May–June

Cladogenesis is the term used to describe the branching off of new taxa. These branches — or clades — are based on several criteria which make the descendants along a particular branch different from their ancestors and from related taxa on other branches. Each new branch exhibits a combination of novel characteristics that are unique to that branch mixed with some "familial" characteristics which this branch shares with its evolutionary ancestors.

Reports of the National Center for Science Education

Title: 

Entropy in Muffins: Why Evolution Does Not Violate the Second Law of Thermodynamics

Author(s): 

Patricia Princehouse, Case Western Reserve University

Year: 

2005

Date: 

September–December

Please note: This text is part of Species, Kinds, and Evolution, by John Wilkins, Reports of NCSE 26 (4), 2006.

Summary of 26 species concepts

Reports of the National Center for Science Education

Title: 

The Evolution of Biological Complexity

Author(s): 

Finn Pond
Whitworth College

Year: 

2006

Date: 

May–June

Introduction

The origin of biological complexity is not yet fully explained, but several plausible naturalistic scenarios have been advanced to account for this complexity. “Intelligent design” (ID) advocates, however, contend that only the actions of an “intelligent agent” can generate the information content and complexity observed in biological systems.