introductiontolifescience-180905020133.pptx
- 2. There are many theories about 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
- 3. THE ORIGIN OF LIFE
- 4. PRIMORDIAL SOUP THEORY Primordial soup, or prebiotic soup, is a hypothetical condition of the Earth's atmosphere before the emergence of life. It is a chemical environment in which the first biological molecules were formed under natural forces. 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.
- 5. The first form of life is believed to have appeared some 3.5 billion years ago. The first evidence of life is found in microfossils. 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. Some of the remains of organisms do not have a nucleus so they were called prokaryotes. EARLY FORMS OF LIFE
- 6. 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. 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.
- 7. The cyanobacteria are the first photosynthetic organisms to form. Their microfossils are among the easiest to recognize. Their morphology remained the same and they left chemical fossils in the form of broken products from pigments.
- 8. Multicellular organisms are believed to have evolved from unicellular eukaryotes. Some single eukaryotic cells, like unicellular algae, formed multicellular aggregates through association with another cell producing colonies. 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 According to Charles Darwin, organisms change over time as a result of adaptation to their environment in order to survive. HOW DID MULTICELLULAR ORGANISMS EVOLVE?
- 9. End of the first topic
- 10. LESSO N 2 CLASSICAL EXPERIMENTS THAT LEADS TO THE DISCOVERY OF FIRST LIFE
- 11. At the end of this lesson, you should be able to describe classic experiments that model conditions which may have enabled the first forms of life to evolve. OBJECTIVES How did Life Begin on Earth?
- 12. One of these theories is the primordial soup theory proposed by Alexander Oparin and John Haldane. According to this theory, life started in a primordial soup of organic molecules. Chemicals from the atmosphere and some form of energy from lightning combined to make amino acids which are the building blocks of protein. Several scientists conducted different experiments that modeled conditions which may have enabled the first life forms to evolve
- 13. About 4.6 billion years ago, the Earth began to exist. The existence of life, as believed by many scientists, started from the moment the Earth’s environment became stable to support life. Several theories were proposed to explain life’s origin. One of these theories is the primordial soup theory proposed by Alexander Oparin and John Haldane. According to this theory, life started in a primordial soup of organic molecules. Chemicals from the atmosphere and some form of energy from lightning combined to make amino acids which are the building blocks of protein. HOW DID LIFE BEGIN ON EARTH?
- 14. Stanley Miller and Harold Urey verified the primordial soup theory by simulating the formation of organic molecules on the early Earth. ELECTRICAL DISCHARGE EXPERIMENT 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.
- 15. 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.
- 16. THERMAL SYNTHESIS 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.
- 17. Jack Szostak contemplated on how early life forms formed in a primordial chemical environment. He then thought that the simplest possible living cells or protocells just required two components to be formed: THE PROTOCELL EXPERIMENT a nucleic acid genome to transmit the genetic information and a lipid sac which encapsulated the genome and let itself grow and divide. Szostak built lipid sacs made in fatty acids and a replicase – an RNA molecule that catalyzes its own replication, in the test tube.
- 18. He found out that lipid sacs with more RNA grew faster. He suggested that such test tube evolution was possible. The results suggested that the early forms of life with just a single gene, an RNA gene, could have undergone a Darwinian evolution.
- 19. Try to leave a piece of bread on the table for two to three weeks. What do you think will happen to it? How will you relate this to the experiments about the origin of life? TRY IT!
- 20. Which of the three experiments is the most plausible in determining the origin of life? Why? WHAT DO YOU THINK?
- 21. END OF SECOND LESSON
- 22. Lesson 3 THE CONNECTIONS AND INTERACTIONS AMONG LIVING THINGS
- 23. At the end of this lesson, you should be able to describe how unifying themes (e.g., structure and function, evolution, and ecosystems) show the connections among living things and how they interact with each other and with their environment. OBJECTIVE:
- 24. HOW ARE THESE UNITS CONNECTED TO EACH OTHER?
- 25. is the branch of biology that deals with the study of living organisms and their relationships with each other and their environment. WHAT IS ECOLOGY? Let’s take the diagram in the previous slide as an example. The diagram depicts that everything is connected and interrelated with one another. They are different from each other, but they co-exist with one another in one community. The unifying themes of life give us an idea of how each of these themes contributes to the connection and interaction of living organisms and
- 26. BIOLOGICAL SYSTEMS A system consists of related parts that interact with each other to form a whole. It has different parts, but each plays a significant role for the whole to function as one. Without the help from each other, it cannot fully perform its function.
- 27. LEVELS OF ORGANIZATION The cells are considered as the basic unit of life. All living organisms are made up of cells. When cells come together, they form the tissues. A group of tissues that perform the same functions form the organs. A group of organs that works together form the different organ systems. An organism consists of many organ systems but functions as one individual.
- 28. The function of an organism or a part of an organism greatly depends on its form and structure. It is related to how it works. FORMS AND FUNCTIONS An example of this is the webbed foot of a duck which helps the duck swim and search for their food under water. Others birds have different structures of feet used for perching and grasping food.
- 29. Reproduction ensures the survival of species. All living organisms reproduce either through asexual or sexual reproduction. In asexual reproduction, the offspring inherits the genes from a single parent. REPRODUCTION AND INHERITANCE Some examples of animals that undergo asexual reproduction include earthworms, hydra, planaria, and bacteria. Animals that undergo sexual reproduction include some reptiles, fishes, insects, and mammals. However in sexual reproduction, the offspring inherit the genes from two individual parents.
- 30. Living organisms obtain energy from the food they eat. Plants undergo photosynthesis where they convert the energy from the sun into sugar. Since most of the animals cannot produce their own energy, they get the energy from the consumption and assimilation of the biomass of plants and other animals. ENERGY AND LIFE
- 31. The ability of an organism to regulate their internal conditions is called homeostasis. THERMAL REGULATION Humans have to maintain a body temperature of 37 C. When the temperature outside our bodies becomes hot, the skin cools down by perspiration, maintaining the normal body temperature.
- 32. In a world that is continuously changing, life itself evolves. Evolution is the change in the physical and heritable traits of organisms over successive generations. Organisms change over time to acclimate to their environment in order to survive. If they fail to adapt to the changes, they usually become extinct. ADAPTATION AND EVOLUTION The Baiji white dolphin, for example, became extinct due to diminished food supply and in addition to that, the pollution caused by human activities. One contemporary example of adaptation is the Aedes aegypti or the mosquito famous for carrying dengue that caused major outbreaks nationwide. Their eggs were able to survive with scarce or no rainwater which is essential to their life cycle. Evolution takes time, usually decades. However, there are times when change happens very rapidly. One example is the blue moon butterfly that managed to undergo a mutation which allows the males to survive an infection of a parasite.
- 33. Look around you and identify the living organisms that surround you. What makes them similar to one another? What makes them different? EXPLORE!