Ch 06 - Evolution12th Biology
The Big Bang Theory
How does the Big Bang Theory explain the origin of the universe, and what is its estimated age?
How does the Big Bang Theory explain the origin of the universe, and what is its estimated age?
The Big Bang Theory:
- Explains the origin of the universe as a singular huge explosion (unimaginable in physical terms) from a very dense point.
- As the universe expanded, the temperature drastically dropped, allowing the formation of gases like Hydrogen and Helium.
- Gravitational forces condensed these gases to form galaxies.
- Age of the Universe: Almost 13.8 billion years old.
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Conditions of Early Earth
What were the specific environmental and atmospheric conditions of the primitive Earth (formed 4.5 billion years ago) before life appeared?
What were the specific environmental and atmospheric conditions of the primitive Earth (formed 4.5 billion years ago) before life appeared?
- Lack of Atmosphere: There was no proper atmosphere on early Earth.
- Reducing Environment: The surface was covered by Water Vapour (), Methane (), Carbon Dioxide (), and Ammonia () released from molten mass.
- UV Radiation: UV rays from the sun broke water into Hydrogen and Oxygen. The lighter escaped.
- Ozone Formation: Oxygen combined with ammonia and methane to form water, , and the ozone layer.
- Ocean Formation: As the Earth cooled, water vapour condensed and fell as rain, filling depressions to form oceans.
Prism Memory Hook
WMAC - 'Whack' the early earth (Water, Methane, Ammonia, CO2)
Chemical Formation of Primitive Atmosphere
Once UV rays broke water vapour into Hydrogen and free Oxygen, how did this early Oxygen interact with other gases to shape the Earth's primitive atmosphere?
Once UV rays broke water vapour into Hydrogen and free Oxygen, how did this early Oxygen interact with other gases to shape the Earth's primitive atmosphere?
Early Atmospheric Reactions:
- The lighter Hydrogen gas () escaped Earth's gravity.
- The highly reactive free Oxygen () violently combined with Ammonia () and Methane ().
- Products: This continuous chemical reaction produced Water (), Carbon Dioxide (), and other gases.
- Ozone: The remaining free oxygen atoms combined to form the protective Ozone layer ().
Prism Memory Hook
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Also in this chapter
41 more cards to study in Prism
- 4The Panspermia Hypothesis
- 5Disproving Spontaneous Generation
- 6Oparin-Haldane Theory
- 7Miller's Spark Discharge Experiment
- 8Timeline of First Life Forms
- 9Evolution of Early Oxygenic Photosynthesis
- 10Lamarck's Theory of Evolution
- 11Key Concepts of Darwinian Theory
- 12Darwin's Concept of Fitness
- 13Hugo de Vries' Mutation Theory vs. Darwinism
- 14Factors Affecting Hardy-Weinberg Equilibrium
- 15The Founder Effect
- 16Operations of Natural Selection
- 17Paleontological Evidence
- 18Embryological Support for Evolution
- 19Hardy-Weinberg Principle
- 20Biochemical Evidence for Evolution
- 21Homologous Organs & Divergent Evolution
- 22Analogous Organs & Convergent Evolution
- 23Artificial Selection as Evolutionary Proof
- 24Industrial Melanism (Directional Selection)
- 25Evolution by Anthropogenic Action
- 26Adaptive Radiation
- 27Parallel Adaptive Radiations
- 28Chronology of Early Animal Evolution
- 29Discovery of the Coelacanth
- 30Formation of Coal Deposits
- 31Rise and Extinction of the Dinosaurs
- 32Secondary Aquatic Adaptation in Reptiles
- 33Evolution of the First Mammals
- 34Fully Aquatic Mammals
- 35Continental Drift and Mammalian Fauna
- 36Early Primates: 15 Million Years Ago
- 37The First Upright Primates
- 38Australopithecines
- 39Homo habilis: The First Hominid
- 40Homo erectus
- 41Neanderthal Man
- 42Rise of Modern Homo sapiens
- 43Extinction of the Dinosaurs
- 44Pre-historic Cave Art and Agriculture
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