Introduction to Biology

Jul 11, 2024

Introduction to Biology

Key Concepts

  1. Cell Theory

    • All living things are composed of cells.
    • All cells arise through cell division.
    • Cells grow, produce proteins, divide, and multiply thanks to metabolism (converting food into energy and building materials).

  2. Genetics

    • Cells store data in DNA molecules.
    • Genes are units of memory in DNA.
    • DNA can store immense amounts of data (e.g., 1 gram of DNA can store 215 petabytes).
    • DNA replication can lead to mutations, altering characteristics of organisms and their offspring.

  3. Evolution

    • Mutations can be favorable or unfavorable.
    • Natural selection favors organisms with advantageous traits.
    • Evolution is driven by natural selection.

  4. Homeostasis

    • Ability to maintain equilibrium of physiological processes.
    • Regulatory mechanisms respond to external perturbations (e.g., mammals regulating core temperature).

Characteristics of Life

  • Composed of cells
  • Ability to maintain homeostasis
  • Undergo metabolism
  • Have a life cycle
  • Ability to grow
  • Adapt to the environment
  • Reproduce

Classification of Life

  1. Bacteria

    • Single-celled organisms with simple structure.
    • Lack nucleus; DNA floats freely.
    • Live in diverse environments, some cause diseases.

  2. Eukaryotes

    • Have a nucleus.
    • Protists: Unicellular organisms that form colonies.
    • Plants: Multicellular, able to photosynthesize.
    • Fungi: Like plants but can't photosynthesize, have chitin in cell walls.
    • Animals: Multicellular, specialized tissues and organs, get nutrients from organic material, capable of movement.

Additional Life Forms

  • Viruses, viroids, prions, and AI: Not considered life forms due to their inability to reproduce sexually.

Sub-disciplines of Biology

  • Cytology: Study of cells.
  • Biochemistry: Study of chemical reactions in cells.
  • Anatomy: Study of organs and their structures.
  • Genetics: Study of genomes.
  • Paleontology: Study of prehistoric life.
  • Ecology: Study of interactions between living beings and the environment.
  • Botany, Zoology, Mycology: Study of plants, animals, and fungi, respectively.
  • Astrobiology: Study of life in the universe.
  • Bioinformatics: Analysis of biological data.

Humorous Note

  • Quantum Biology: Satirical reference to international relations in the South Pacific during the 90s.

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