Earth and Life Science - Origin of Life

Earth and Life Science - Lesson 1: The Origin of Life

• Theories of the Origin of Life:
  • Spontaneous Generation: Life arises from non-living matter.
  • Biogenesis: Life originates from pre-existing life.
  • Panspermia: Life originated elsewhere and was transported to Earth.
  • Special Creation: Life was created by a supernatural being.
  • Primordial Soup Theory: Proposed by Alexander Oparin and John Haldane, life originated in a "soup" of organic molecules formed by energy from lightning interacting with atmospheric chemicals. Early Earth's oceans were filled with simple organic molecules (CHNOPS) essential for life.
• Classical Experiments Supporting the Primordial Soup Theory:
  • Miller-Urey Experiment: Simulated early Earth's atmosphere with gases like methane, ammonia, water, and hydrogen; demonstrated the formation of amino acids.
  • Sidney Fox Experiment: Demonstrated the formation of proteinoid microspheres (protocells) by heating amino acids.
  • Jack Szostak Experiment: Investigated the formation of protocells from nucleic acids and lipids, suggesting that early life forms with a single RNA gene could have evolved.
• Early Life Forms:
  • First evidence of life dates back to 3.5 billion years ago.
  • Earliest life forms were prokaryotes, single-celled organisms without a nucleus.
  • Cyanobacteria, the first photosynthetic organisms, played a crucial role in oxygenating Earth's atmosphere.

Lesson 2: Unifying Theme of Life

• Organization: Life is organized from the atomic level to the biosphere level. Cells form tissues, organs, organ systems, and ultimately organisms. Organisms interact within populations, communities, ecosystems, and the biosphere.
• Adaptation and Evolution: Evolution explains the unity and diversity of life. Organisms adapt to their environment to survive and those with favorable traits are more likely to reproduce. Natural selection drives this process, leading to changes in species over time.
• Regulation and Homeostasis: Organisms maintain internal balance (homeostasis) in diverse environments, such as maintaining body temperature and blood glucose levels.
• Energy Processing: Living organisms obtain and process energy. Autotrophs produce their own food (e.g., plants through photosynthesis). Heterotrophs obtain energy by consuming other organisms.
• Growth and Development: Organisms follow a pattern of growth and development based on their genetic code. Cells divide and differentiate, leading to increased size and complexity.
• Response to Stimuli: Living organisms respond to changes in their environment (stimuli), such as movement, contraction, or changes in behavior.
• Reproduction and Heredity: Reproduction ensures species survival. Asexual reproduction involves a single parent, and sexual reproduction two. Heredity is the passing of traits from parents to offspring through genes.

Lesson 3: Animal Reproduction

• Asexual Reproduction: Reproduction that does not require two parents. Offspring is an exact copy of the parent. Common forms include fission, fragmentation, budding.
• Sexual Reproduction: Reproduction that requires two parents. Fertilization, the union of egg and sperm cells, can happen internally or externally.

Lesson 4: Genetic Engineering

• Genetic Engineering: Altering an organism's DNA to create new species, resulting in genetically modified organisms (GMOs).
• Techniques of Genetic Engineering:
  • Artificial Selection (Breeding)
  • Hybridization
  • Inbreeding
  • Cloning
  • Natural and Artificial Cloning
  • Gene Splicing
  • Recombinant DNA Technology
• Applications of Genetic Engineering:
  • Genetically Modified Bacteria (e.g., for producing human insulin)
  • Genetically Modified Plants (e.g., Bt corn, golden rice)
  • Genetically Modified Animals (e.g., bioluminescent animals)
• Ethical Considerations of GMOs: Benefits (increased production, pest resistance, etc.) and risks (allergic reactions, etc.).
• Safety of GMOs: Extensive research shows GMO foods are safe for human consumption.

Lesson 5: Organ Systems

• Digestive System: Receives, breaks down, and absorbs food. Eliminates unabsorbed material.
• Respiratory System: Intake and output of air, exchange of gases between air and blood.
• Skeletal System: Support, protection, movement, storage of minerals, blood cell production.
• Cardiovascular System: Transports substances throughout the body. (Blood).
• Urinary System: Removes waste from blood, maintains water and electrolyte balance, eliminates waste.
• Muscular System: Movement, posture, heat generation.
• Lymphatic System: Returns tissue fluid to blood, defends the body against infection.

Lesson 6: Evolution

• Early Theories of Evolution:
  • Jean-Baptiste Lamarck's Theory of Inheritance of Acquired Traits; Use and Disuse. Examples: Appendix, wisdom teeth, tailbone.
  • Charles Darwin's Theory of Evolution by Natural Selection. Natural Selection: The differential survival and reproduction of individuals based on their heritable traits. Common Descent: All living organisms share a common ancestor. Gradualism: Evolution occurs gradually. Multiplication of Species: New species arise from existing species.
• Evidences of Evolution: Fossil Records; Comparative Anatomy (Homologous and Analogous Structures); Comparative Embryology; Comparative Biochemistry.

Lesson 7: Biotic Potential and Environmental Resistance

• Ecology: Study of living organisms and their interactions with each other and their environment.
• Ecosystems: Biological community of interacting organisms and their physical environment.
• Ecosystem Stability: Conditions for stability include a constant energy source (sun), living organisms that convert energy into organic compounds, recycling of materials, and abiotic/biotic factors.
• Population Growth Rate: Dependent on biotic potential and environmental resistance. Biotic Potential: A species' ability to survive and reproduce. Environmental Resistance: Factors that limit population growth, e.g., lack of food, disease, predators.
• Population Dynamics: All individuals of a species in an area. Demography: Statistical study of populations. Population Size, Density, Dispersion.

Lesson 8: Factors Affecting Population Density

• Density-Dependent Regulation: Factors affecting population density and growth rates based on population density, e.g., diseases, competition, predation.
• Density-Independent Regulation: Factors that affect population density regardless of density, e.g., weather, natural disasters.
• Types of Biological Interactions: Neutralism, Mutualism, Commensalism, Amensalism, Parasitism, Parasitoidism, Predation, Competition.
• Biotic Potential: Ability of a population to grow under ideal conditions.

Lesson 9: Classification of Organisms

• Generalist: Organisms that can live in various habitats, have a wide diet, and are adaptable to changing conditions.
• Specialist: Organisms with specific resource needs, limited habitat preferences, and are more vulnerable to environmental changes.