Evolutionary Biology and Taxonomy: Contributions by Linnaeus, Darwin, Wallace, and Mayr laid the foundation for understanding biodiversity and the classification of life.
Cell Theory and Molecular Biology: Discoveries by Schleiden, Schwann, Virchow, Watson, and Crick revolutionized our understanding of cellular structures and genetic material.
Plant Physiology and Photosynthesis: Von Sachs, Priestley, and Engelmann made significant advancements in understanding how plants produce and use energy, which has implications for agriculture and ecology.
Genetics and Heredity: Mendel's laws, Morgan’s experimental work, and the chromosomal theory of inheritance explain how traits are passed down through generations, leading to modern genetic science.
Medical and Environmental Sciences: Fleming’s discovery of penicillin and contributions from figures like Swaminathan and Borlaug demonstrate how scientific advancements have transformed agriculture and healthcare.
This summary highlights key scientists and their major contributions to the field of biology. The content is aligned with the NCERT syllabus, covering fundamental discoveries and milestones in biological research.
.jpeg "Notable Scientists and Their Contributions to Biology (Classes 11th & 12th)")
1. Ernst Mayr (20th Century)
Known as the "Darwin of the 20th century."
Awarded the triple crown of biology for his contributions to evolutionary biology.
2. Carolus Linnaeus (18th Century)
Introduced the system of binomial nomenclature.
Proposed the two-kingdom classification system and the artificial system of classification.
3. Aristotle (4th Century BCE)
One of the earliest to attempt scientific classification of living organisms.
4. R.H. Whittaker (1969)
Developed the five-kingdom classification system.
5. Carl Woese
Proposed the six-kingdom classification, advancing Whittaker's system.
6. D.J. Iwanosky (19th Century)
Identified viruses as causal organisms of tobacco mosaic disease, discovering they were smaller than bacteria.
7. W.M. Stanley (20th Century)
Proved that viruses could be crystallized, showing that they consist largely of proteins.
8. Bentham and Hooker
Developed the natural system of classification, advancing plant taxonomy.
9. Katherine Esau
Studied the spread of viruses in plants and was a leading figure in plant biology well into her old age.
10. Linus Pauling
Published models of protein structures, specifically the α-helix and β-sheet.
11. Robert Brown (1831)
Discovered the nucleus in plant cells, a landmark in cellular biology.
12. Matthias Schleiden and Theodor Schwann (1838–1839)
Proposed the cell theory, stating that all plants and animals are made of cells.
13. Rudolf Virchow
Expanded on cell theory, asserting that all cells arise from pre-existing cells ("Omnis cellula e cellula").
14. George Palade (1953)
Discovered ribosomes, now known as Palade particles.
15. Julius Von Sachs (1860)
Pioneered hydroponics and demonstrated the production of glucose in plants, a critical step in understanding photosynthesis.
16. Joseph Priestley (1774)
Discovered oxygen and recognized its importance in plant growth.
17. T.W. Engelmann
Developed the first action spectrum for photosynthesis, illustrating how different wavelengths of light affect the process.
18. Hans Krebs
Proposed the Krebs cycle (citric acid cycle), a fundamental metabolic pathway in cellular respiration.
19. Gregor Mendel (1856-1863)
Conducted pioneering work on heredity in pea plants, formulating the foundational laws of genetics.
20. Thomas Morgan
Proved the chromosomal theory of inheritance and is considered the father of experimental genetics.
21. Watson and Crick (1953)
Proposed the double helix model of DNA, a breakthrough in molecular biology.
22. Maurice Wilkins & Rosalind Franklin
Provided X-ray diffraction data crucial to the discovery of the DNA double helix structure.
23. Erwin Chargaff
Formulated Chargaff's rules, establishing base-pairing regularities in DNA.
24. Alfred Hershey & Martha Chase
Confirmed that DNA, not protein, is the genetic material through experiments with bacteriophages.
25. Hargobind Khorana
Developed methods to synthesize RNA molecules, advancing the understanding of genetic code and protein synthesis.
26. Louis Pasteur
Disproved the theory of spontaneous generation and laid the groundwork for microbiology.
27. Charles Darwin (19th Century)
Formulated the theory of natural selection and evolution, revolutionizing biological science.
28. Alfred Wallace
Independently arrived at similar conclusions to Darwin on natural selection.
29. Hugo De Vries
Introduced the concept of saltation in evolution, emphasizing sudden large mutations.
30. M.S. Swaminathan
Known as the "Father of the Green Revolution" in India for his role in agricultural development.
31. Norman E. Borlaug
Developed semi-dwarf wheat varieties, significantly contributing to the Green Revolution globally.
32. Alexander Fleming
Discovered penicillin, the first antibiotic, transforming the treatment of bacterial infections.
33. Herbert Boyer & Stanley Cohen
Developed recombinant DNA technology, marking the beginning of modern genetic engineering.
34. Ramdeo Misra
Known as the "Father of Ecology" in India for his pioneering work in the field.
35. Edward Wilson
Popularized the term "biodiversity" and contributed to ecological and evolutionary studies.
FAQs on Notable Scientists in Biology
1. Who is known as the "Darwin of the 20th century"?
Answer: Ernst Mayr is referred to as the "Darwin of the 20th century" due to his significant contributions to evolutionary biology.
2. What is binomial nomenclature, and who introduced it?
Answer: Binomial nomenclature is a system of naming organisms using two terms: the genus and species. It was introduced by Carolus Linnaeus.
3. What is the significance of R.H. Whittaker’s five-kingdom classification?
Answer: R.H. Whittaker’s five-kingdom classification provided a more comprehensive system for categorizing living organisms based on their cellular organization and modes of nutrition.
4. Who discovered the cell nucleus?
Answer: The cell nucleus was discovered by Robert Brown in 1831.
5. What are Mendel's contributions to genetics?
Answer: Gregor Mendel’s experiments with pea plants laid the foundation for genetics, leading to the formulation of the laws of inheritance, such as the law of segregation and the law of independent assortment.
6. What is the Krebs cycle, and why is it important?
Answer: The Krebs cycle, proposed by Hans Krebs, is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate. It’s essential for cellular respiration.
7. Who are Watson and Crick, and what did they discover?
Answer: James Watson and Francis Crick discovered the double helix structure of DNA, which is crucial to understanding genetic information storage and transmission.
8. What did Louis Pasteur contribute to microbiology?
Answer: Louis Pasteur disproved the theory of spontaneous generation and developed the germ theory of disease, which laid the foundation for modern microbiology and vaccinations.
9. What is recombinant DNA technology, and who pioneered it?
Answer: Recombinant DNA technology involves combining DNA from different organisms to create new genetic combinations. It was pioneered by Herbert Boyer and Stanley Cohen.
10. Who is known as the "Father of the Green Revolution" in India?
Answer: M.S. Swaminathan is known as the "Father of the Green Revolution" in India for his role in improving agricultural production through the introduction of high-yielding crop varieties.
11. Who first proposed the theory of natural selection?
Answer: The theory of natural selection was proposed by Charles Darwin, with Alfred Wallace independently arriving at similar conclusions.
12. What did Rosalind Franklin contribute to the discovery of DNA?
Answer: Rosalind Franklin provided crucial X-ray diffraction images of DNA, which helped Watson and Crick to decipher the double helix structure.
13. What is Chargaff's rule in DNA?
Answer: Chargaff’s rule states that in DNA, the amount of adenine (A) always equals thymine (T), and the amount of guanine (G) equals cytosine (C), ensuring base-pairing regularity.
14. What is the significance of the five-kingdom classification?
Answer: The five-kingdom classification by R.H. Whittaker categorizes organisms into Monera, Protista, Fungi, Plantae, and Animalia, based on characteristics such as cell structure and nutrition.
15. Who coined the term "biodiversity"?
Answer: Edward Wilson popularized the term "biodiversity" and significantly contributed to its study in ecological and evolutionary biology.
