Earth's History PowerPoint PDF

EARTH’S HISTORY  LESSON OBJECTIVES Describe general features of the history of life on earth, including generally accepted dates and sequence of the geologic time scale and characteristics of major groups of organisms present during these time periods. Value the importance o...

EARTH’S HISTORY  LESSON OBJECTIVES Describe general features of the history of life on earth, including generally accepted dates and sequence of the geologic time scale and characteristics of major groups of organisms present during these time periods. Value the importance of learning the history of life to the future of science Create a timeline a personal timeline and compare with the geologic time scale  LESSON 2: HISTORY OF LIFE 1. WHAT IS THE AGE OF THE EARTH? 2. WHAT WAS THE EARTH LIKE MILLION OF YEARS AGO? 3. WHEN DID MAN FIRST APPEAR ON EARTH? The first widely accepted idea of how life on Earth formed was proposed by the Russian chemist Alexander Ivanovich Oparin (1894-1980) in the 1920s He proposed that the atmosphere of early Earth was very reactive, with numerous incidents of lightning and high levels of ultraviolet radiation. Oparin thought that the early oceans contained a solution of many essential elements and compounds. He referred to it as a "primordial soup," wherein the earliest forms of life arose through a series of reactions that made simple compounds become complex  THE ORIGIN OF LIFE Geologic pieces of evidence show that Earth was not formed from a single event. Our planet was formed by different pieces of cosmic debris that were probably attracted to one another over a course of about 100 million years. As it was forming, it was struck by one or more meteorlike objects, possibly one as large as Mars. The collision most probably produced enough heat to melt the entire globe. When Earth melted, the different elements contained in it rearranged themselves according to density. The densest elements formed the core of Earth. From there, radioactive decay generated enough heat to convert the interior of Earth into molten rock. No life-form would have been able to survive that kind of harsh environment  FIRST ORGANIC MOLECULES Electrical Discharge Experiment Stanley Miller and Harold Urey verified the primordial soup theory by simulating the formation of organic molecules on the early Earth. They confined methane, ammonia, water, and hydrogen in a closed system and applied continuous electrical sparks to trigger the formation of the building blocks of life. After a day, they observed a change of color in the solution. After a week, the solution was tested, and they found out that several amino acids were produced. The purpose of this experiment was not to try and produce amino acids, rather, its purpose was to explore the conditions of the early Earth and what the naturally occurring results would be.  Sidney Fox demonstrated in his experiment the origin of life using a specific mixture of pure, dry amino acids. In his experiment, after heating the mixture, an aqueous solution was formed and cooled into microscopic globules called protenoid microspheres. The globules looked like coccoid bacteria and seemed to be budding, which is a form of reproduction in some microorganisms.  He claimed that the protenoid microspheres constituted protocells – almost true cells, and multiplied through division like true cells. He believed that these cells were the link between the primordial environment and the true living cells.  EVOLUTION OF RNA AND DNA One of the hypotheses about the origin of life, suggests that RNA could have evolved before DNA due to three conditions. First, protein synthesis may occur in RNA but not in DNA. Second, RNA can catalyze certain reactions in the form of ribozymes. Last, the enzymatic reduction of RNA nucleotides enables the synthesis of DNA nucleotides. These RNA nucleotides were able to replicate, synthesize proteins, and store information.  ORIGIN OF EUKARYOTIC CELLS Complex life began from simple prokaryotic organisms, which are said to be the ancestors or precursors of eukaryotes. Eukayogenesis occurred Paleoproterozoic era. Prokaryotes are so successful in an incredible range of habitats that they can even live in swamps, hindguts of termites, hot springs, and even in deep sea and underground rocks About two billion years ago, they began forming internal cell membranes. Then, something radical seemed to have happened because primitive prokaryotes entered the ancestral eukaryote. They did not infect their host; instead, they formed an endosymbiotic relationship with it. Endosymbiosis is a type or relationship wherein an organism lives inside its partner.  According to the endosymbiotic theory, eukaryotic cells created a symbiotic relationship with prokaryotic organisms-one group can produce ATP, and the other group can do photosynthesis.  These organisms became mitochondria and chloroplasts, respectively. Due to modern technology and the subsequent study of the endosymbiotic theory, scientists are able to support the theory's claim.  MULTICELLULARITY AND SEXUAL REPRODUCTION Most prokaryotes reproduce asexually. After eukaryotic cells arose, they began to reproduce sexually. This event caused the rapid evolution of more complex life-forms. The reason behind this far greater speed of evolution is the shuffling and reshuffling of genes from one generation to the next. These changes in genetic information result in increased chances of evolutionary changes in a species. After the emergence of sexual reproduction, there came the development of multicellular organisms from single-celled species Paleontology  Paleontology is the scientific study of the existence of life, including the origin and eventual destruction or extinction of different groups of organisms. It is a science that incorporates different disciplines such as biology, geology, ecology, archaeology, and even computer science to study the evolution of organisms and how they interact with the environment.  Paleontologists specialize in studying the ecologies of the past and the evolution of organisms that thrived in these ecologies through careful observation and documentation of fossils. They work to identify the forms of life that existed millions of years ago.  They figure out how things were in ancient times using fossil records. It is a fossil of Archaeopteryx lithographica from the late Jurassic period. The Archaeopteryx is said to have had many features of dinosaurs, which provide a strong evidence of the dinosaur ancestry of birds Geology Geology is the study of life on Earth based on the evidence found on rocks. Geologists have a lot of contribution in terms of studying the history of life on Earth. Geologists are scientists who carefully study the different materials that make up Earth. They work to understand the history of Earth by focusing on the changes of Earth over time in relation to changes in climate and land formation. They specifically investigate rock formations and even fossils to measure different physical properties of Earth. To summarize, paleontologists look at the fossil remains of different types of organisms beneath the surface of Earth to study primitive life, and geologists study the outer layer of Earth's crust to understand the history of Earth. Both of them work together to understand the history or evolution of life on Earth. Both of them use the geologic time scale to divide Earth's history into time intervals. LESSON 3- GEOLOGIC TIME  Geologic Time requires an understanding of the Laws of Nature. It means that how things work today is the same as they were before. It never changed. The discovery of fossils or rocks is very helpful to scientists because it can be used as an instrument to interpret the past.  The division of Geologic Time is based on the significant events on Earth. The layers on the surface of the Earth, from the recent origin down to the most ancient, made possible to split Geological Time into Eons, Eras and Periods. These are the periods that divide the history and evolution of Earth. STRATIFIED ROCKS The layering that occurs in most sedimentary rocks and in those igneous rocks formed at the Earth's surface, as from lava flows and volcanic fragmental deposits. The layers range from several millimetres to many metres in thickness and vary greatly in shape Methods to Determine the Age of Stratified Rocks  Relative dating is a method of arranging geological events based on the rock sequence.  Absolute dating is a method that gives an actual date of the rock or period of an event.  Relative Dating This method uses stratigraphy, and according to this method the top most layer is the most recent event as asserted by the law of superposition (chronostratic time) is the subdivisions of Earth geology represented by rocks, fossil records, and order of geological events. These subdivisions in Earth geology and time are globally recognized and accepted by introducing integrated geologic time scale. The events in Earth history are ordered from bottom (older events) to top (younger events) in the geologic time scale which has relative geologic time names. These names are grouped by units in descending order: eons, eras, periods, epochs, and ages.  Absolute Dating This method can tell which sediments are deposited from and the approximate age of the specimen. Most absolute dating methods use radiometric methods, where radioactive minerals are used to compute the age of rocks, Isotopes which are present at radioactive minerals, breakdown at a constant rate. This rate of decay is known, so if you can measure the parent and daughter isotope, you can calculate when the rocks are formed.  At present, the Geologic Time Scale is divided into big portions of time known as EONS. Eons are further divided into ERAS. Eras are divided into PERIODS. The Precambrian Eon is the point of time in which our planet started to form. During this time, there was no formation of any organism. What are evident are the abiotic features of the earth. It represents more than 80 percent of the total records of geologic time and supported with pieces of evidence found in rocks. During the Phanerozoic Eon, living organisms like plants and animals existed. It constitutes the time of multicellular life on Earth and the evolutionary process happened. This eon is further divided into the Paleozoic Era, Mesozoic Era, Cenozoic Era. Significant events of Earth are used to determine the boundaries of every Era. Phanerozoic Eon Precambrian Eon PALEOZOIC ERA Lasted 290 million years, plants and reptiles began moving from the sea to the land. The era has been divided into six periods: Permian, Carboniferous, Devonian, Silurian, Ordovician, and Cambrian. Cambrian - 542-488 million years ago, The Cambrian Explosion marks this period with a rapid increase in the diversity of life. Trilobites, an early group of arthropods were dominant along with early representatives of most major animal phyla, including brachiopods and archaeocyathids (reef-building sponges).  Ordovician - 488-443 million years ago, This period saw the rise of diverse marine life, including the first coral reefs, with the dominance of brachiopods, bryozoans, and the continued success of trilobites. Early jawless fish (agnathans) also appeared. But this diversty was cut due to the first mass extinctions that occur. The Late Ordovician extinction (86%) Likely caused by a short, intense ice age that led to sea level drop and habitat loss. Silurian - 443-416 million years ago The Silurian period is noted for the development of the first vascular plants and the diversification of fish, including the first jawed fish (gnathostomes). Coral reefs became more complex, and the first land-dwelling arthropods, like millipedes, appeared. Devonian - 416 to 359 Million years ago, known as the "Age of Fishes," the Devonian period saw the rise of various fish groups, including the first sharks and bony fish. The first tetrapods (four-limbed vertebrates) also appeared, marking significant progress in the colonization of land. But this era was ended due to the Late Devonian Extinction (75%) Possibly related to widespread anoxia (lack of oxygen) in the oceans, volcanic activity, or asteroid impacts. Carboniferous - 359 to 299 Million years ago During this period, vast swampy forests of ferns, horsetails, and clubmosses dominated the landscape, leading to the formation of extensive coal deposits. Insects and early amphibians were the dominant terrestrial vertebrates. Permian -299 to 252 Million years ago, The Permian period saw the rise of early reptiles and the first mammal-like reptiles. Dominant terrestrial plants included gymnosperms (like conifers). The period ended with the an extinction event, the largest mass extinction in Earth's history, Permian-Triassic Extinctions (96%) Likely caused by massive volcanic eruptions , leading to climate change, ocean acidification, and anoxia. MESOZOIC ERA Lasted 187 million years, This era was the reign of the reptiles and has witnessed the rise and fall of the dinosaurs. The era has been divided into three periods: Triassic, Jurassic and Cretaceous. Triassic - 252 to 199 Million years ago, The first dinosaurs began to appear, with early forms like Eoraptor and Herrerasaurus. Reptiles like Archosaur were also significant. Dinosaurs became more diverse, and early ancestors of modern crocodiles and mammals also appeared. During this time another mass extinctions occured.The Triassic-Jurrasic Extinction(80%) Possibly triggered by volcanic activity (Central Atlantic Magmatic Province), leading to climate change and ocean acidification. Jurassic -199 to 145 Million years ago, Dinosaurs became more prominent, with notable examples like Dilophosaurus and Stegosaurus. Early birds, like Archaeopteryx, also emerged. Large sauropod dinosaurs such as Brachiosaurus and Diplodocus dominated, alongside predatory theropods like Allosaurus. The first true birds, such as Ichthyornis, appeared. Cretaceous -145 to 65 Million years ago, Dinosaurs continued to diversify, with large theropods like Spinosaurus and sauropods like Brachiosaurus still present. Flowering plants (angiosperms) also began to spread. The period saw the dominance of large theropods like Tyrannosaurus rex and giant herbivores such as Triceratops. This period also saw the proliferation of flowering plants and the first appearances of many modern insect groups. Despite the dominance of this dinasours another mass extinction occur the Creteaceous-Paleogene extinction, it is attributed to a combination of volcanic activity and an asteroid impact. CENOZOIC ERA Begins 65 million years up to now, After the end of the reign of the mighty dinasours, mammals began to dominate, this era was divided into three periods: Paleogene, Neogene and Quarternary Paleogne - 65 to 23 Million years ago Early mammals began to diversify, including forms like Paleocene and Purgatorius. Early ancestors of modern groups began to appear. Modern mammal families emerged, such as early horses, whales, and primates. Flowering plants continued to diversify. Neogene - 65 to 23 Million years ago Many modern mammal families appeared, including early forms of horses, elephants, and bovids. Early hominids also began to evolve. The expansion of grasslands led to the rise of large grazing mammals and continued evolution of early human ancestors. Quarternary - 23 Million to 10 Thousand years ago Pleistocene Epoch: Characterized by Ice Ages and the presence of megafauna such as woolly mammoths and saber-toothed cats. Early humans began to spread globally. Holocene Epoch: The current period, marked by the development of human civilizations, the rise of modern flora and fauna, and significant environmental changes due to human activities. ACTIVITY 2- MY PERSONAL TIMELINE Create a timeline a personal timeline. Your output will be evaluated the following: Accuracy, Content/ Relevance to the topic, Sequence( date & time), Creativity. Submission will be on Monday –January 13,2025