Layers of the Earth

  • Crust: Thinnest layer, where we live (0-100 km thick).
  • Mantle: Thick, semi-solid rock, flows slowly, drives plate tectonics.
  • Outer Core: Liquid iron and nickel, generates Earth's magnetic field.
  • Inner Core: Solid iron and nickel, immense pressure.

Natural Disasters

  • Earthquakes: Sudden energy release along fault lines.
  • Volcanoes: Magma rising to the surface.
  • Tsunamis: Large waves caused by underwater disturbances.
  • Importance of Plate Tectonics: Helps predict and mitigate impacts of disasters.

Solar System

  • Composed of the Sun and gravitationally bound objects.
  • Planet Classification:
    • Terrestrial: Rocky (Mercury, Venus, Earth, Mars).
    • Gas/Ice Giants: (Jupiter, Saturn, Uranus, Neptune).
  • The Sun: Primary energy source for life on Earth.

Climate Change

  • Definition: Long-term shift in global temperatures and weather patterns.
  • Primary Cause: Enhanced greenhouse effect due to human activities (fossil fuel burning).
  • Impacts: Rising sea levels, extreme weather, and ecosystem disruption.

Human Body Systems

  • Circulatory: Transports oxygen, nutrients, wastes (via heart/blood vessels).
  • Nervous: Rapid communication and control (electrochemical signals).
  • Endocrine: Slower regulation (hormones).
  • Homeostasis: Stable internal environment maintained by these systems.

Cell Structure

  • Prokaryotes: Lack a nucleus (e.g., bacteria).
  • Eukaryotes: Have a nucleus and organelles (e.g., plants, animals).
  • Key Organelles:
    • Mitochondria: Cellular respiration (energy production).
    • Ribosomes: Protein synthesis.
  • Cells: Basic functional unit of all living things.

Genetics

  • Study of heredity; DNA: Blueprint of life organized into genes.
  • Alleles: Different versions of a gene.
  • Significance: Explains trait inheritance and biological variation.

Ecosystems and Biodiversity

  • Ecosystem: Community and its non-living environment.
  • Biodiversity: Variety of life (species, genetic, ecosystem diversity).
  • Higher biodiversity: Indicates healthier and more resilient ecosystems.