Here is a comprehensive glossary of scientific terms across five major fields: Biology, Evolution, Astronomy, Geology, and Physics. Each term includes a clear definition and relevant context to enhance understanding.

📘 Glossary of Scientific Terms

🔬 Biology

1. Cell

  • The basic structural and functional unit of all living organisms.

  • Types: Prokaryotic (no nucleus) and Eukaryotic (with nucleus).

2. DNA (Deoxyribonucleic Acid)

  • The molecule that carries genetic information in living organisms.

  • Composed of nucleotides: adenine, thymine, cytosine, and guanine.

3. Homeostasis

  • The ability of an organism or cell to maintain stable internal conditions despite external changes.

4. Photosynthesis

  • The process by which plants, algae, and some bacteria convert sunlight into chemical energy.

  • Equation: CO₂ + H₂O + sunlight → C₆H₁₂O₆ + O₂.

5. Mutation

  • A change in the DNA sequence that can lead to variations in traits and sometimes diseases.

🧬 Evolution

6. Natural Selection

  • The process by which organisms better adapted to their environment tend to survive and reproduce more successfully.

7. Speciation

  • The evolutionary process by which new biological species arise.

8. Abiogenesis

  • The hypothesis that life arose naturally from non-living matter on the early Earth.

9. Common Descent

  • The concept that all living organisms share a common ancestor.

10. Gene Flow

  • The transfer of genetic material between populations, contributing to genetic diversity.

🌌 Astronomy

11. Big Bang Theory

  • The leading explanation of the origin of the universe, stating it began as a singularity ~13.8 billion years ago and has been expanding since.

12. Black Hole

  • A region of space with gravity so intense that not even light can escape from it.

13. Exoplanet

  • A planet that orbits a star outside our solar system.

14. Nebula

  • A cloud of gas and dust in space, often a region where new stars are born.

15. Redshift

  • The phenomenon where light from distant galaxies is stretched toward the red end of the spectrum, indicating the universe’s expansion.

🌍 Geology

16. Plate Tectonics

  • The theory that Earth’s outer shell is divided into plates that move, causing earthquakes, mountain formation, and continental drift.

17. Fossil

  • The preserved remains or traces of organisms from the remote past, often found in sedimentary rock.

18. Sedimentary Rock

  • Rock formed by the accumulation of sediments, often layered and containing fossils.

19. Erosion

  • The process by which natural forces like water, wind, or ice wear away soils and rocks.

20. Radiometric Dating

  • A method of dating geological or archaeological specimens by measuring the decay of radioactive isotopes.

⚛️ Physics

21. Atom

  • The smallest unit of ordinary matter, composed of protons, neutrons, and electrons.

22. Entropy

  • A measure of disorder or randomness in a system; a central concept in the second law of thermodynamics.

23. Quantum Mechanics

  • The branch of physics that deals with the behavior of particles on the atomic and subatomic scale.

24. Relativity (Einstein’s Theory)

  • A theory explaining how time and space are linked for objects moving at a consistent speed in a straight line. Includes both special and general relativity.

25. Gravity

  • The force that attracts two bodies toward each other, proportional to their masses and inversely proportional to the square of the distance between them.

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