Evolving Concept of Life (PDF)

Evolving Concept of Life Based on Emerging Pieces of Evidence Earth and Life Science – Second Quarter: Lesson 1 After going through this module, you 1. Identify the sequence are expected to: of events of the history of life on earth; 2. Name the...

Evolving Concept of Life Based on Emerging Pieces of Evidence Earth and Life Science – Second Quarter: Lesson 1 After going through this module, you 1. Identify the sequence are expected to: of events of the history of life on earth; 2. Name the pieces of evidence on the evolution of life on earth; and 3. Recognize the importance  We live in a planet, Earth, which we knew as the only planet where life may exists. But, how did life exist? How did Theories on Origin of Life Theory 1. Creation 2. Panspermia 3. Theory of Abiogenesis 4. Theory of Biogenesis 5. Primordial Soup Theory  Theories on Origin of Life 1. Creation Theory - The concept of divine creation is that all life forms existing today on Earth have been created by a supreme being.  Theories on Origin of Life 2. PANSPERMIA proposes that organisms such as bacteria, complete with their DNA, could be transported by means such as comets through space to planets including Earth.  Theories on Origin of Life 3. Theory of Abiogenesis - This is also called the spontaneous generation theory that states that living things were created from non-living things like simple organic  Theories on Origin of Life 4. Theory of Biogenesis - This theory states that living things came from living things or animate objects.  Theories on Origin of 5. Primordial Soup TheoryLife (Stanley Miller and Harold Urey in 1952) PRIMITIVE SOUP refers to the primitive water bodies on the earth that were rich in organic matter and from which scientists believe that the first life forms  Theories on Origin of Life 5. Primordial Soup Theory (Stanley Miller and Harold Urey in 1952) Explains the origin of life via transformation of hydrocarbons to biomolecules.  Theories on Origin of Life 5. Theory of Catastrophism - This theory states that there have been several creations from God, each encountering a catastrophe, completely destroying them. Each new creation consisted of new life forms different from the previous one.  Early Forms of Life The universe is about 4.6 billion years old. (Hadean) The first form of life is believed to have appeared some 3.5 billion years ago. Fossil records show the emergence of the different life forms. The first evidence of life is found in microfossils.  Microfossil Aresfossils that contain the remains of tiny plants and animals. They are very small and can be measured in millimeters, and some can only be identified under a microscope. 4.6 -3.8 BYA – The earth is said to be violent because of the meteorites and volcanic eruptions and zircon crystal was formed. Researchers have confirmed the crystal is the oldest rock fragment ever found on Earth.  3.5 BYA –Life on Earth initially began with prokaryotes, discovered in sedimentary rock formations called stromalites. Archean (Period of Stromatolite, layered Appearance of first deposit, mainly of prokaryotes) limestone, formed by the growth of blue-green 3.0 BYA – The first photosynthetic organism thrived the earth which is blue green algae are called cyanobacteria. These primitive bacteria produce oxygen during photosynthesis These findings marked the beginning of eukaryotic  2.0 BYA – The appearance of the first eukaryotes and the influx of multicellular organisms occurred 1.2 Proterozoic Eon billion years ago. The (Period of appearance of the first eukaryote) oldest eukaryotic body fossil is the multicellular 500 BYA – The Paleozoic era when the trilobites and the cephalopods became dominant in the ocean particularly during the Cambrian and Ordovician. 251-65.5 MYA – The Mesozoic era (age of reptile) Triassic, Jurassic, and Cretaceous period. Dinosaurs are dominant. 65.5 MYA the start of the Cenozoic era followed mass extinction and modern mammal orders diversified. 250 TYA – The Cenozoic era (recent life) Homo erectus have eolved. Activity 1: Create a timeline of earth using the following picture to show the order of the history of life on earth. Thank you!