Biology Introduction Notes

Summary:

The document discusses various topics related to biology, including the characteristics of living beings, levels of ecological organization, the scientific method, biogenesis versus abiogenesis, and the origin of life on primitive Earth. Here’s a summarized breakdown of the main points:

1. Characteristics of Living Beings:
   • Living beings are categorized as unicellular or multicellular organisms.
   • Essential chemical elements in living matter include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulphur.
   • Living matter comprises organic (proteins, glycides, lipids, nucleic acids) and inorganic (water, mineral salts) compounds.
   • Cellular organization involves atoms, molecules, organelles, cells, tissues, organs, systems, and organisms.
   • Metabolism includes anabolism (building molecules) and catabolism (breaking down molecules).
2. Levels of Ecological Organization:
   • Hierarchical organization in nature includes atoms, molecules, organelles, cells, tissues, organs, systems, organisms, populations, communities, biotopes, ecosystems, and the biosphere.
3. Hypothetico-Deductive/Scientific Method:
   • The scientific method involves observation, question formulation, hypothesis/deduction, experimentation, results analysis, conclusions, and potential theory revision.
   • Hypotheses should be testable and lead to predictions that can be confirmed or refuted through experiments.
4. Biogenesis versus Abiogenesis:
   • Biogenesis asserts that life arises from pre-existing life, supported by experiments conducted by Redi, Pasteur, and others.
   • Abiogenesis suggests that life can emerge spontaneously from non-living matter.
   • Historical figures like Aristotle, Needham, and Spallanzani played roles in developing these theories.
5. The Origin of Life on Primitive Earth:
   • The Oparin-Haldane hypothesis proposes chemical evolution, suggesting the formation of organic molecules in the presence of water vapour and energy sources like lightning.
   • The Miller-Urey experiment simulated early Earth conditions and produced simple organic compounds like amino acids.
   • Other theories discussed include panspermia, evolutionism, creationism, and fixism.

Excerpt:

Biology Introduction Notes

SUMMARY

INTRODUCTION – BIOLOGY

1. Characteristics of Living Beings
2. Levels of Ecological Organization
3. Hypothetico-Deductive/Scientific Method
4. Biogenesis versus Abiogenesis
5. The origin of Life on primitive Earth

CHARACTERISTICS OF LIVING BEINGS

Chemical Composition of Living Matter

Everything in nature, including living beings, is compounded by atoms. However, some chemical elements are always present in living matter:
– Carbon (C), Hydrogen (H), Oxygen (O) and Nitrogen (N) – in a significant quantity.
– Phosphorus (P) and Sulphur (S) – in a smaller amount.