Introduction to Life Science PDF

Introduction to Life Science  The Origin of Life Some believed that living organisms were put to Earth by some divine forces. Others say that life did not originate from Earth but from other planets. But among scientists, the most accepted theory is that life came from inanimate matter The Or...

Introduction to Life Science  The Origin of Life Some believed that living organisms were put to Earth by some divine forces. Others say that life did not originate from Earth but from other planets. But among scientists, the most accepted theory is that life came from inanimate matter The Origin of Life Alexander Ivanovich Oparin a Soviet biochemist was notable for his theories about the origin of life and also for his book The Origin of Life. He also studied the biochemistry of material processing by plants and enzyme reactions in plant cell. The Origin of Life John Scott Haldane a physiologist is famous for intrepid self- experimentation which led to many important discoveries about human body and the nature of gases. The Origin of Life Oparin-Haldane hypothesis suggested that if the primitive atmosphere was reducing (as opposed to oxygen-rich), and if there was an appropriate supply of energy, such as lightning or ultraviolet light, then a wide range of organic compounds might be synthesized. The Origin of Life Oparin-Haldane hypothesis The Origin of Life Oparin-Haldane hypothesis The Origin of Life Oparin-Haldane hypothesis Haldane coined the term ‘prebiotic soup’ or ‘prebiotic atmosphere’ that consisted of an abundance of methane, ammonia and water. This term became a powerful symbol of the Oparin-Haldane view of the origin of life. The Origin of Life Oparin-Haldane hypothesis According to the primordial soup theory proposed by Alexander Oparin and John Haldane, life started in a primordial soup of organic molecules. Some form of energy from lightning combined with the chemicals in the atmosphere to make the building blocks of protein known as the amino acids. The Origin of Life Oparin-Haldane hypothesis According to the primordial soup theory proposed by Alexander Oparin and John Haldane, life started in a primordial soup of organic molecules. Some form of energy from lightning combined with the chemicals in the atmosphere to make the building blocks of protein known as the amino acids.  Early Forms of life The first form of life is believed to have appeared some 3.5 billion years ago. The evidence of life is found in microfossils.  Early Forms of life Microfossils are fossils that contain the remains of tiny plants and animals. They are very small and can be measured in millimeters, and some could only be identified under a microscope.  Early Forms of life Some of the remains of organisms do not have a nucleus so they were called prokaryotes. They are known to be the earliest forms of life. They have survived the extreme conditions of the early environment. They started to make their own food by utilizing the energy from the sun and the carbon dioxide in the atmosphere.  Early Forms of life These are the photosynthetic organisms. The process of photosynthesis produced more oxygen that changed the Earth’s early atmosphere. This change in the atmosphere allowed oxygen- breathing organisms to exist.  Early Forms of life The cyanobacteria are the first photosynthetic organisms to form. The first microfossil that showed remains of organisms with differences in structure from the simple form of life was seen in rocks about 1.5 billion years old. They are larger than bacteria and have internal membranes and thicker wall. These findings marked the beginning of eukaryotic organisms on Earth.  How did multicellular organisms evolve? Multicellular organisms are believed to have evolved from unicellular eukaryotes. From colonial aggregates, the organisms evolved to form multicellular organisms through cell specialization. Protozoans, sponges and fungi came to being. The first fossilized animals which were discovered 580 million years ago were soft-bodied. The continuous process of cell specialization brought the emergence of complex and diverse plants and animals, including human beings. Activity No. 1: Picture Analysis Direction: Study and analyze the diagram shown below and answer the process questions. Activity No. 1: Picture Analysis Process Questions: 1. What was the first form of life? 2. When in Earth’s history did life develop? 3. How long did it take for complex life to develop? Activity No. 2: Test your understanding