Periods in Geologic Time
Academia Interamericana de Panamá
Science Speech Written Report
*Geologic time*
Aleks Ch. # 8
Date: 24/07/2013
Introduction
The age of Earth is as vast in time as the universe is vast in space. It is not easy to really get a "feel" for 4,600 million years! One way to try to get a "feel" for how big it is, is to break the number down into smaller pieces that perhaps we can understand.
Plants and animals have changed many times, from amoebas to dinosaurs to people. The age of Earth is so long compared to all periods of time that we humans are familiar with, it has been given a special name: Geologic time.
Geologic time is the time measure used by geologists, paleontologists, and other earth scientists to describe the timing and relationships between events that have occurred throughout Earth 's history.
The largest defined unit of time is the supereon, composed of eons. Eons are divided into eras, which are in turn divided into periods, epochs and ages. The terms eonothem, erathem, system, series, and stage are used to refer to the layers of rock that correspond to these periods of geologic time in earth 's history.
Geologists qualify these units as Early, Mid, and Late when referring to time, and Lower, Middle, and Upper when referring to the corresponding rocks.
Geologic units from the same time but different parts of the world often look different and contain different fossils, so the same period was historically given different names in different locales.
To describe the geologic time, scientists use the geologic time scale, which is a system of chronological measurement that relates stratigraphy to time.
Objective
With this speech we will learn about:
1. Which are the main divisions in geologic time scale?
2. What characterizes the Precambrian time?
3. What characterizes the Paleozoic Era?
4. What characterizes the Mesozoic Era?
5. What characterizes the Cenozoic Era?
Precambrian Time
The Precambrian time
Science Speech Written Report
*Geologic time*
Aleks Ch. # 8
Date: 24/07/2013
Introduction
The age of Earth is as vast in time as the universe is vast in space. It is not easy to really get a "feel" for 4,600 million years! One way to try to get a "feel" for how big it is, is to break the number down into smaller pieces that perhaps we can understand.
Plants and animals have changed many times, from amoebas to dinosaurs to people. The age of Earth is so long compared to all periods of time that we humans are familiar with, it has been given a special name: Geologic time.
Geologic time is the time measure used by geologists, paleontologists, and other earth scientists to describe the timing and relationships between events that have occurred throughout Earth 's history.
The largest defined unit of time is the supereon, composed of eons. Eons are divided into eras, which are in turn divided into periods, epochs and ages. The terms eonothem, erathem, system, series, and stage are used to refer to the layers of rock that correspond to these periods of geologic time in earth 's history.
Geologists qualify these units as Early, Mid, and Late when referring to time, and Lower, Middle, and Upper when referring to the corresponding rocks.
Geologic units from the same time but different parts of the world often look different and contain different fossils, so the same period was historically given different names in different locales.
To describe the geologic time, scientists use the geologic time scale, which is a system of chronological measurement that relates stratigraphy to time.
Objective
With this speech we will learn about:
1. Which are the main divisions in geologic time scale?
2. What characterizes the Precambrian time?
3. What characterizes the Paleozoic Era?
4. What characterizes the Mesozoic Era?
5. What characterizes the Cenozoic Era?
Precambrian Time
The Precambrian time
Bibliography: http://en.wikipedia.org/wiki/Precambrian http://science.nationalgeographic.com/science/prehistoric-world/precambrian/ http://en.wikipedia.org/wiki/Paleozoic_era http://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event http://www.ucmp.berkeley.edu/exhibit/geology.html http://www.ucmp.berkeley.edu/help/timeform.php http://www.cotf.edu/ete/modules/msese/earthsysflr/geotime.html