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Introduction to Biology

• Biology is the study of living organisms.
• It's derived from two Greek words:
  • Bios meaning life
  • Logy meaning study.
• Biology studies single-celled organisms like bacteria, cellular processes, and multicellular organisms like animals, plants, and fungi.
• It also covers classification, behavior, evolution, and interactions with different ecosystems.

Brief History of Biology Development

• Biology examines organisms in terms of shape, structure, origin, development, heredity, organ functions, lifecycles, distribution, and relationship with their environment.

Old Classification System

• The old classification divided living things into two kingdoms:
  • Animal kingdom: includes animals
  • Plant kingdom: includes plants
• This system categorized organisms into animal and plant kingdoms based on their structural features.

New Classification System

• Whittaker proposed a new five-kingdom system in 1969.
• This system distinguishes between prokaryotic and eukaryotic organisms.
• It classified living organisms into five kingdoms:
  • Protista
  • Fungi
  • Plantae
  • Animalia
  • Monera

Prokaryotes and Eukaryotes

• Prokaryotes are single-celled organisms lacking a nucleus and membrane-bound organelles.
• Eukaryotes have membrane-bound organelles, including a nucleus, and can be single-celled or multi-celled.