History Of The Earth PDF

HISTORY OF THE EARTH  LEARNING OBJECTIVES At the end of the lesson, learners should be able to: describe how layers describe the different of rocks (stratified methods (relative and rocks) are formed absolute dating) to determin...

HISTORY OF THE EARTH  LEARNING OBJECTIVES At the end of the lesson, learners should be able to: describe how layers describe the different of rocks (stratified methods (relative and rocks) are formed absolute dating) to determine the age of stratified rocks  LEARNING OBJECTIVES At the end of the lesson, learners should be able to: explain how relative describe how marker fossils and absolute dating (also known as guide fossils) were used to are used to define and determine the identify subdivisions of the subdivisions of geologic time scale geologic time  LEARNING OBJECTIVES At the end of the lesson, learners should be able to: describe how the Earth’s history can be interpreted from the geologic time scale  INTRODUCTION Earth is an active place. The Earth’s history is recorded in the rocks of the crust. Earthquakes rip along plate boundaries, volcanoes spew fountains of molten lava, and mountain ranges and seabed are constantly created and destroyed. Earth scientists have long been concerned with deciphering the history – and predicting the future – of  INTRODUCTION Over the past four decades, Earth scientists have made great strides in understanding Earth’s working. Scientists also used an assumption called uniformitarianism in order to relate what we know about present day processes to past events – the present is the key to the past. Uniformitarianism  What is Geologic Time The geologic time scale is a system Scale? of chronological measurement that relates stratigraphy to time. It is used by geologists to describe the timing and relationships between events that have occurred throughout Earth’s history. Geologists have divided Earth’s history into a series The system used by scientist to relate stratigraphy and time to any geologic events is called geologic time scale. They have divided Earth’s 4.6 billion age history into different spans of time to conveniently indicate events. These time spans include age (millions of years), epoch (tens of millions of years), period (one hundred million years),era (several hundred million years)and eon (half a billion years or The ideas of superposition and evolution provide the basis of the geological time scale, which was developed in a somewhat random fashion (mostly in Europe) during the 19th century. The geologic time scale is a system of chronological dating that relates geological strata to time. It is used by geologists, paleontologists and other Earth scientists to describe  The geological time scale divides the history of Earth into eons, eras, periods and epochs.  EON It has the largest intervals of geologic time. A single eon covers a period of several hundred million years. The history of the Earth has been divided into three eons: Archaean, Proterozoic and  EON Archaean Eon – it is the period where life first formed on Earth, archea and bacteria. Earth cooled down and was able to support continents and oceans.  EON Proterozoic Eon – it is the period just before the proliferation of complex life on Earth. There were extensive shallow epicontinental seas and rocks are less metamorphosed than  EON Phanerozoic Eon – it is the period of visible life where rapid expansion and evolution of life forms occur and fill the various ecological niches available on Earth. The time between Earth’s formation and the beginning of the Paleozoic era are often collectively called the Precambrian time or also known as the “time of hidden life”. This era ranges from 4.6 billion years ago when the Earth formed to about 544 million years ago when abundant microscopic life appeared.  ERA It is the subdivision of eons. The geologic time scale is divided into three eras – Paleozoic (time of ancient life), the Mesozoic (time of middle life) and the Cenozoic (time of recent life).  ERA It is the subdivision of eons. The geologic time scale is divided into three eras – Paleozoic (time of ancient life), the Mesozoic (time of middle life) and the Cenozoic (time of recent life).  ERA PALEOZOIC First 544 Mya ERA appearance of organisms with hard parts – specific event: The  ERA MESOZOIC Extinction of 250 Mya ERA dinosaurs and many other organisms. A major event of this era was the breakup of Pangea. At the end of this era, the dinosaurs and  ERA CENOZOIC ERA Extinction 65 Mya of different Mammals and pre- historic  Epoch and Periods Each era is further divided into periods and further into epochs.  Six Major Periods in Paleozoic Era  Periods of Paleozoic Era Cambri Almost all marine organisms came an into existence as evidenced by abundant fossils. One important Period event is the development of organisms having the ability to secrete calcium carbonate and calcium phosphate for the formation of shells. The evolution of chordates, animal with dorsal nerve cord, hard resembled clams and arthropods Cambrian Period Cambrian Period  Periods of Paleozoic Era Ordovic This period marked the earliest ian appearance of vertebrates and Period the jawless fish known as Agnatha. Ordovician rocks have distinction of occurring at the highest elevation on Earth – the top of Mount Everest. During this period, the level of carbon dioxide was several higher than Ordovician Period  Periods of Paleozoic Era Silurian This period brought the emergence Period of terrestrial life, the earliest well developed circulatory system (vascular plants) known as Cooksonia. As plants move ashore so did other terrestrial organisms. Airbreathing scorpions and millipedes were common during the period. Romundina, a primitive armoured fish with a cartilage skeleton is the earliest fish known to Ordovician Period Ordovician Period  Periods of Paleozoic Era Devonia This period was known as the “age of n Period fishes”. Lowland forests of seed ferns, scale trees and true ferns flourished. Sharks and bony fishes developed. Today the lung fishes and coelacanth, a “living fossil” have such internal nostrils and breathe in a similar way. The first amphibians made their appearance, although able to live on land, they Devonian Period  Periods of Paleozoic Era Carbonife Warm, moist climate conditions rous contributed to lash Period vegetation and dense swampy forests. Insects under rapid evolution led to such diverse forms of giant cockroaches and dragonflies. The evolution of the first reptiles took place with the development of the amniotic egg, a porous shell Carboniferous Period  Periods of Paleozoic Era Permian A dramatic climatic shift may have Period been partially triggered the assembly of smaller continents into a supercontinent, Pangea which was surrounded by an immense ocean called Panthalassa. The reptiles were well-suited to their environment that they ruled the Earth for 200 million years. The two major groups Permian Period Three Major Periods in Mesozoic Era  Periods of Mesozoic Era Triassic The Triassic Period (252-201 million Period years ago) began after Earth's worst-ever extinction event devastated life. The Permian- Triassic extinction event, also known as the Great Dying, took place roughly 252 million years ago and was one of the most significant events in the history of our planet. When 90% of life in the oceans and  Periods of Mesozoic Era Trias By the start of the Triassic, all the Earth's sic landmasses had coalesced to form Pangaea, Perio a supercontinent shaped like a giant C that d straddled the Equator and extended toward the Poles. Conifers, cycadophytes, ginkgoes, ferns and large arborescent horsetails dominated the landscape. The seas became inhabited by large marine reptiles. On land, ancestral forms of various modern amphibians arose, as did reptiles such as turtles and crocodilians. By the Late Triassic, archosaurs were becoming more and more Triassic Period  Periods of Mesozoic Era Jurass Interval of geologic time, 201.3– ic Period 145 million years ago, that is one of the three major divisions of the Mesozoic Era. It was preceded by the Triassic Period and followed by the Cretaceous. During the Jurassic, Pangea began to break up into the present-day continents. Marine  Periods of Mesozoic Era Jurass On land, ferns, mosses, cycads, and ic conifers thrived, some developing Period flowerlike structures in place of cones. The dinosaurs rose to supremacy on land, and by the end of the Jurassic the largest species had evolved. Archaeopteryx, the first primitive bird, appeared before the end of the period. Early mammals, tiny shrew like creatures that Jurassic Period  Periods of Mesozoic Era Cretace Interval of geologic time from ous Period c. 145 million to 66 million years ago. During the Cretaceous the climate was warmer than today. In the seas, marine invertebrates flourished, and bony fishes evolved. On land, flowering  Periods of Mesozoic Era Cretace Mammals and birds remained ous Period inconspicuous throughout the Cretaceous, while the reptiles continued their dominance. The dinosaurs reached the peak of their evolution during this period but rather suddenly became extinct at its Cretaceous Period  Period of Cenozoic Era  Period of Cenozoic Era Tertiary During most of the Tertiary the Period spatial distribution of the major continents was largely similar to that of today. Emergence and submergence of land bridges between continents critically affected the distribution of both terrestrial and marine animals and plants. Virtually all the Epoch of Tertiary Period  Epoch of Tertiary Period Paleoce The Paleocene epoch immediately ne followed the extinction of the Epoch dinosaurs. The Earth's climate was warmer than today, but cooler and drier than the epochs immediately preceding and following it. Europe and North America were connected, as were Asia and North America at times. characterized by significant climate changes, the breakup of  Epoch of Tertiary Period Eocene The Eocene Epoch took place between Epoch 54 and 38 million years ago. Eocene means ''dawn of recent life. '' This is a fitting name, as many of the same mammals we have today, both on land and in the ocean, appeared for the first time during this era. Marks the first appearance in the fossil record of the two completely marine mammal groups, the cetaceans (whales, porpoises, and dolphins) and the sirenians (akin to the  Epoch of Tertiary Period Oligocen The beginning of the e Epoch Oligocene is marked by a sudden decrease in earth's temperature. The Antarctic continent had drifted to its current position at the south pole and a permanent ice cap had started to form. Open plains and deserts became  Epoch of Tertiary Period Miocene The Miocene was a long-lasting epoch in Epoch which the earth's climate rebounded from the cooling of the Oligocene and there was a marked increase in both global temperatures and the total number of mammal species. Though warmer than the Oligocene, the polar ice caps remained in place. The late Miocene was a time of global drying and cooling. As ice rapidly accumulated at the poles, sea- levels fell, rainfall decreased and rainforests retreated. Many plant and  Epoch of Quaternary Period  Period of Cenozoic Era Quatern The Quaternary is subdivided ary Period into the Pleistocene Epoch and the Holocene Epoch and is characterized by major cyclical changes of climate on a global scale. These led to repeated invasions of vast areas by ice sheets. Its major  Period of Cenozoic Era Quatern The dramatic changes of ary Period climate and environment in the Quaternary led to high rates of evolution and extinction, particularly among the mammals. The extinction of many large mammals toward the end of the last ice  Epoch of Quaternary Period  Epoch of Quaternary Period Pleistoc At the height of the Pleistocene glacial ages, ene more than 30% of the land area of the Earth Epoch was covered by glacial ice; during the interglacial stages, probably only about 10% was covered. The animals of the Pleistocene began to resemble those of today, and new groups of land mammals, including humans, appeared. At the end of the epoch, mass extinctions occurred: in North America more than 30 genera of large mammals became extinct within a span of roughly 2,000 years. Of the many causes that have been proposed for these extinctions, the two most likely are  Epoch of Quaternary Period Holocen Formerly Recent Epoch, Latest e Epoch interval of the Earth’s geologic history, dating from about 11,700 years ago to the present. The younger of the two epochs that constitute the Quaternary Period, the Holocene follows the last glacial stage of the Pleistocene Epoch. It is characterized by relatively warm climatic conditions. During this Climates cooled during this era, hence the widespread glaciation. This era also brought about the advent of humans. The lowered sea level resulted in the land bridges connections between land masses. One of these land bridges provided the route for human migration from Asia to North America , also throughout the world.  THANK YOU! I HOPE YOU LEARN SOMETHING NEW TODAY!