{"id":320,"date":"2021-09-16T19:29:16","date_gmt":"2021-09-16T19:29:16","guid":{"rendered":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/chapter\/8-6-understanding-geological-time-physical-geology-2nd-edition\/"},"modified":"2021-09-16T19:43:07","modified_gmt":"2021-09-16T19:43:07","slug":"8-6-understanding-geological-time-physical-geology-2nd-edition","status":"publish","type":"chapter","link":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/chapter\/8-6-understanding-geological-time-physical-geology-2nd-edition\/","title":{"raw":"8.6 Understanding Geological Time -- Physical Geology – 2nd Edition","rendered":"8.6 Understanding Geological Time — Physical Geology – 2nd Edition"},"content":{"raw":"\n\n
[1]<\/sup><\/a>; that is 45,800 times faster than the rate of natural climate change since the Eocene!<\/p>\n

One way to wrap your mind around geological time is to put it into the perspective of single year, because we all know how long it is from one birthday to the next. At that rate, each hour of the year is equivalent to approximately 500,000 years, and each day is equivalent to 12.5 million years.<\/p>\n

If all of geological time is compressed down to a single year, Earth formed on January 1, and the first life forms evolved in late March (roughly 3,500 Ma). The first large life forms appeared on November 13 (roughly 600 Ma), plants appeared on land around November 24, and amphibians on December 3. Reptiles evolved from amphibians during the first week of December and dinosaurs and early mammals evolved from reptiles by December 13, but the dinosaurs, which survived for 160 million years, were gone by Boxing Day (December 26). The Pleistocene Glaciation got started at around 6:30 p.m. on New Year\u2019s Eve, and the last glacial ice left southern Canada by 11:59 p.m.<\/p>\n

It\u2019s worth repeating: on this time scale, the earliest ancestors of the animals and plants with which we are familiar did not appear on Earth until mid-November, the dinosaurs disappeared after Christmas, and most of Canada was periodically locked in ice from 6:30 to 11:59 p.m. on New Year\u2019s Eve. As for people, the first to inhabit B.C. got here about one minute before midnight, and the first Europeans arrived about two seconds before midnight.<\/p>\n

It is common for the popular press to refer to distant past events as being \u201cprehistoric.\u201d For example, dinosaurs are reported as being \u201cprehistoric creatures,\u201d even by the esteemed National Geographic Society.[2]<\/sup><\/a> The written records of our history date back to about 6,000 years ago, so anything prior to that can be considered \u201cprehistoric.\u201d But to call the dinosaurs prehistoric is equivalent to\u2014and about as useful as\u2014saying that Singapore is beyond the city limits of Kamloops! If we are going to become literate about geological time, we have to do better than calling dinosaurs, or early horses (54 Ma), or even early humans (2.8 Ma), \u201cprehistoric.\u201d<\/p>\n

\n
\n

Using the \u201call of geological time compressed to one year\u201d concept, determine the geological date that is equivalent to your birthday. First go to Day Number of the Year Calculator<\/a> to find out which day of the year your birth date is. Then divide that number by 365, and multiply that number by 4,570 to determine the time (in millions since the beginning<\/em> of geological time). Finally subtract that number from 4,570 to determine the date back from the present.<\/p>\n

For example, April Fool\u2019s Day (April 1) is day 91 of the year: 91\/365 = 0.2493. 0.2493 x 4,570 = 1,139 million years from the start of time, and 4,570 \u2013 1,193 = 3,377 Ma is the geological date.<\/p>\n

Finally, go to the Foundation for Global Community\u2019s \u201cWalk through Time\u201d<\/a> website to find out what was happening on your day. The nearest date to 3,377 Ma is 3,400 Ma. Bacteria ruled the world at 3,400 Ma, and there\u2019s a discussion about their lifestyles.<\/p>\n

See Appendix 3 for Exercise 8.5 answers<\/a>.<\/p>\n <\/div>\n <\/div>\n

\n
\n
    \n
  1. Climate change data from NASA Goddard Institute for Space Studies: http:\/\/data.giss.nasa.gov\/gistemp\/tabledata_v3\/GLB.Ts.txt \u21b5<\/a>
    <\/li>\n
  2. http:\/\/science.nationalgeographic.com\/science\/prehistoric-world\/ \u21b5<\/a>
    <\/li>\n <\/ol>\n <\/div>\n <!-- pb_fixme -->\n<\/div>\n<\/div>
    \n <!-- pb_fixme -->\n <!-- pb_fixme -->\n<\/div>\n<\/div>\n","rendered":"
    \n
    [1]<\/sup>; that is 45,800 times faster than the rate of natural climate change since the Eocene!<\/p>\n

    One way to wrap your mind around geological time is to put it into the perspective of single year, because we all know how long it is from one birthday to the next. At that rate, each hour of the year is equivalent to approximately 500,000 years, and each day is equivalent to 12.5 million years.<\/p>\n

    If all of geological time is compressed down to a single year, Earth formed on January 1, and the first life forms evolved in late March (roughly 3,500 Ma). The first large life forms appeared on November 13 (roughly 600 Ma), plants appeared on land around November 24, and amphibians on December 3. Reptiles evolved from amphibians during the first week of December and dinosaurs and early mammals evolved from reptiles by December 13, but the dinosaurs, which survived for 160 million years, were gone by Boxing Day (December 26). The Pleistocene Glaciation got started at around 6:30 p.m. on New Year\u2019s Eve, and the last glacial ice left southern Canada by 11:59 p.m.<\/p>\n

    It\u2019s worth repeating: on this time scale, the earliest ancestors of the animals and plants with which we are familiar did not appear on Earth until mid-November, the dinosaurs disappeared after Christmas, and most of Canada was periodically locked in ice from 6:30 to 11:59 p.m. on New Year\u2019s Eve. As for people, the first to inhabit B.C. got here about one minute before midnight, and the first Europeans arrived about two seconds before midnight.<\/p>\n

    It is common for the popular press to refer to distant past events as being \u201cprehistoric.\u201d For example, dinosaurs are reported as being \u201cprehistoric creatures,\u201d even by the esteemed National Geographic Society.[2]<\/sup><\/a> The written records of our history date back to about 6,000 years ago, so anything prior to that can be considered \u201cprehistoric.\u201d But to call the dinosaurs prehistoric is equivalent to\u2014and about as useful as\u2014saying that Singapore is beyond the city limits of Kamloops! If we are going to become literate about geological time, we have to do better than calling dinosaurs, or early horses (54 Ma), or even early humans (2.8 Ma), \u201cprehistoric.\u201d<\/p>\n

    \n
    \n

    Using the \u201call of geological time compressed to one year\u201d concept, determine the geological date that is equivalent to your birthday. First go to Day Number of the Year Calculator<\/a> to find out which day of the year your birth date is. Then divide that number by 365, and multiply that number by 4,570 to determine the time (in millions since the beginning<\/em> of geological time). Finally subtract that number from 4,570 to determine the date back from the present.<\/p>\n

    For example, April Fool\u2019s Day (April 1) is day 91 of the year: 91\/365 = 0.2493. 0.2493 x 4,570 = 1,139 million years from the start of time, and 4,570 \u2013 1,193 = 3,377 Ma is the geological date.<\/p>\n

    Finally, go to the Foundation for Global Community\u2019s \u201cWalk through Time\u201d<\/a> website to find out what was happening on your day. The nearest date to 3,377 Ma is 3,400 Ma. Bacteria ruled the world at 3,400 Ma, and there\u2019s a discussion about their lifestyles.<\/p>\n

    See Appendix 3 for Exercise 8.5 answers<\/a>.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n

    \n
    \n
      \n
    1. Climate change data from NASA Goddard Institute for Space Studies: http:\/\/data.giss.nasa.gov\/gistemp\/tabledata_v3\/GLB.Ts.txt \u21b5<\/a>
      <\/li>\n
    2. http:\/\/science.nationalgeographic.com\/science\/prehistoric-world\/ \u21b5<\/a>
      <\/li>\n<\/ol><\/div>\n

      <!– pb_fixme –>\n<\/p><\/div>\n<\/div>\n

      \n <!– pb_fixme –>
      \n <!– pb_fixme –>\n<\/div>\n","protected":false},"author":8,"menu_order":70,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-320","chapter","type-chapter","status-publish","hentry"],"part":3,"_links":{"self":[{"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/pressbooks\/v2\/chapters\/320","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/wp\/v2\/users\/8"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/pressbooks\/v2\/chapters\/320\/revisions"}],"predecessor-version":[{"id":973,"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/pressbooks\/v2\/chapters\/320\/revisions\/973"}],"part":[{"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/pressbooks\/v2\/parts\/3"}],"metadata":[{"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/pressbooks\/v2\/chapters\/320\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/wp\/v2\/media?parent=320"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/pressbooks\/v2\/chapter-type?post=320"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/wp\/v2\/contributor?post=320"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/physicalgeology\/wp-json\/wp\/v2\/license?post=320"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}