The Arab World

Latest topics

» Course Book الكتاب الخاص بالكورس
Tue Jan 08, 2013 12:51 am by Meeno1

» كلمات فرنسية من الحياة اليومية مترجمة إلى العربية
Wed Jul 27, 2011 9:55 pm by 3lia2 3li

» Lesson Two الدرس الثانى
Tue Jul 26, 2011 10:01 am by 3lia2 3li

» دورة ICDL مبسطه
Thu Feb 03, 2011 3:45 am by not happy

» فيديوهات دكتور إبراهيم الفقى كاملة
Sun Oct 17, 2010 3:06 am by Mohamed Selim

» Lesson Seven الدرس السابع
Tue Oct 05, 2010 1:33 am by Dr.Ruba

» All Medical Rep And Supervisor Pharmaceutical Companie PMR
Thu Aug 12, 2010 5:39 am by drphtarek

» Lesson One الدرس الأول
Fri Jul 23, 2010 12:15 am by love bird

» ترحيب بالأعضاء الجدد فى منتدى العالم العربى
Thu Jul 22, 2010 11:49 pm by love bird

» ما هو الحيوان الذى تخافه الجن
Wed Jul 14, 2010 2:32 am by saouaa

» Greetings and Courtesies : التحية و المجاملات
Fri Jun 11, 2010 5:50 am by Mohamed Selim

» شكر خاص لكل اللى ساهموا فى نجاح هذا الكورس التعليمى
Thu Jun 10, 2010 2:14 am by emy

» ألغاز العالم العربى
Thu Jun 10, 2010 2:07 am by Mohamed Selim

» بإمكان مصر انت تصبح اغنى دول العالم واغنى من دول الخليج . بحث للدكتور نادر نور الدين
Mon Jun 07, 2010 3:24 am by Mohamed Selim

» زوج يرسل إيميل بالغلط
Wed Jun 02, 2010 7:33 pm by Mohamed Selim

» عناوين شركات البترول فى مصر
Mon May 17, 2010 1:42 am by emy

» Lesson Four الدرس الرابع
Sat May 15, 2010 11:15 pm by emy

» دكتور إبراهيم الفقى - سلسة قوة الثقة بالنفس
Sat May 15, 2010 2:35 pm by ساره

» مقياس الحقيقة
Thu May 13, 2010 7:32 pm by planner

» نكت جااااااااااااامدة
Thu May 13, 2010 1:16 pm by Mohamed Selim

December 2018


Calendar Calendar

Who is online?

In total there is 1 user online :: 0 Registered, 0 Hidden and 1 Guest


[ View the whole list ]

Most users ever online was 20 on Wed May 05, 2010 3:47 am

The Arab World

free counters


    Mohamed Selim

    Posts : 106
    Join date : 2010-04-25
    Age : 31
    Location : Egypt


    Post by Mohamed Selim on Tue May 04, 2010 2:58 pm


    Geologists have divided Earth history into units displayed in the geologic time scale (Table 1–1). The units are called eons, eras, periods, and epochs and are identified primarily by the types of life that existed at the various times. The two earliest eons, the Hadean and Archean, cover the first 2.5 billion years of Earth history.

    Life originated during Archean time. Living organisms then evolved and proliferated during the Proterozoic Eon (protero is from a Greek root meaning “earlier” or
    “before” and zoon is from the Greek word meaning “life”). However, most Proterozoic organisms had no hard parts such as shells and bones. Most were single
    celled, although some multicellular organisms existed.

    The Proterozoic Eon ended about 538 million years ago. Then, within an astonishingly short time—perhaps as little as 5 million years—many new species evolved.
    These organisms were biologically more complex than their Proterozoic ancestors, and many had shells and skeletons. The most recent 13 percent of geologic time,
    from 538 million years ago to the present, is called the Phanerozoic Eon (phaneros is Greek for “evident”). The Phanerozoic Eon is subdivided into the Paleozoic Era
    (“ancient life”), the Mesozoic Era (“middle life”), and
    the Cenozoic Era (“recent life”)


      Current date/time is Mon Dec 10, 2018 3:04 am