Biology (AKU-BIO)
Topic 1 of 7Aga Khan Board

Introduction to Biology

The science of life

Biology is the scientific study of living organisms. It is divided into many branches:

  • Botany — the study of plants
  • Zoology — the study of animals
  • Microbiology — the study of microscopic organisms
  • Ecology — the study of organisms and their environment
  • Genetics — the study of heredity and genes

    • Scientists use the biological method:

  • Observation — noticing something interesting
  • Hypothesis — a testable explanation
  • Experiment — testing the hypothesis
  • Data collection — recording results
  • Conclusion — accepting or rejecting the hypothesis

    • The cell is the basic unit of all life. Animal cells have: cell membrane, cytoplasm, nucleus, mitochondria, ribosomes. Plant cells have everything animal cells have, PLUS: cell wall (cellulose), chloroplasts (photosynthesis), and a large central vacuole.


    Life is organized into levels: Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere

    Key Points to Remember

    • 1Branches of biology
    • 2Biological method
    • 3Cell structure
    • 4Biological organization

    Pakistan Example

    Mangroves of Karachi — A Living Biology Lesson

    The mangrove forests along Karachi's coastline demonstrate multiple branches of biology. Botanists study the plants, zoologists study crabs and fish, microbiologists study bacteria in the water. The mangroves are cells → tissues → organs working together to survive saltwater.

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    Human Body Systems