Crash Course: Biology Hank Green teaches you biology! Learn, study and understand the science of life. Topics covered range from: taxonomy, systems, biological molecules, photosynthesis, evolution, animals, plants, anatomy, and ecology.
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0:0012:58Crash Course Big History #4: The Origin of Life - YouTubeYouTubeStart of suggested clipEnd of suggested clipHi I'm John Green and welcome to crash course big history where today we are going to get a life orMoreHi I'm John Green and welcome to crash course big history where today we are going to get a life or at least the earth is going to get a life but first today we have to start with a disclaimer.
After things cooled down, simple organic molecules began to form under the blanket of hydrogen. Those molecules, some scientists think, eventually linked up to form RNA, a molecular player long credited as essential for life's dawn. In short, the stage for life's emergence was set almost as soon as our planet was born.
Theory of special creation II. Abiogenesis or Theory of Spontaneous Creation or Autobiogenesis III. Biogenesis (omne vivum ex vivo) IV. Cosmozoic or Extraterrestrial or Interplanetary or Panspermiatic theory.
ProkaryotesProkaryotes were the earliest life forms, simple creatures that fed on carbon compounds that were accumulating in Earth's early oceans. Slowly, other organisms evolved that used the Sun's energy, along with compounds such as sulfides, to generate their own energy.
We know that life began at least 3.5 billion years ago, because that is the age of the oldest rocks with fossil evidence of life on earth. These rocks are rare because subsequent geologic processes have reshaped the surface of our planet, often destroying older rocks while making new ones.
Life began at deep-sea vents The deep-sea vent theory suggests that life may have begun at submarine hydrothermal vents spewing elements key to life, such as carbon and hydrogen-, according to the journal Nature Reviews Microbiology (opens in new tab).
Big Ideas: All living things have certain traits in common: Cellular organization, the ability to reproduce, growth & development, energy use, homeostasis, response to their environment, and the ability to adapt. Living things will exhibit all of these traits.
Life on earth cannot survive without water. It is a precious natural resource. Water supports all human, plant and animal life. We use it to produce food, manufacture goods and sustain health.
IN 4.5 billion years of Earthly history, life as we know it arose just once. Every living thing on our planet shares the same chemistry, and can be traced back to “LUCA”, the last universal common ancestor.
approximately 3.5 billion years oldThe oldest known fossils are approximately 3.5 billion years old, but some scientists have discovered chemical evidence suggesting that life may have begun even earlier, nearly 4 billion years ago.