In a nutshell, biology is the branch of science that deals with living beings and the vital processes that drive them. Modern sub branches of biology have been a long time in the making, with many important scientists and thinkers throughout history contributing towards them in more ways than one.
While we can’t make a list of all of them here, we can count down the most notable contributions that led to our modern, advanced understanding of the tree of life on Earth – from Darwin’s seminal work on the theory of evolution and natural selection to the mapping of the human genome by the Human Genome Project.
10. Leonardo Da Vinci’s Anatomy Illustrations
Leonardo da Vinci is known for his artistic masterpieces like the Mona Lisa and The Last Supper. Not many people, however, know about his pioneering contributions to anatomical studies, as Da Vinci was one of the first academic artists in history to provide accurate, detailed drawings of the human anatomy.
His fascination with human anatomy began during his apprenticeship, likely influenced by the works of his master Verrocchio and neighbor Pollaiuolo. By the 1490s, da Vinci’s anatomical interest had grown into independent research, resulting in practical dissections of around 30 corpses throughout his lifetime.
Leonardo’s early studies focused on the skeleton and muscles, later evolving to include the brain, heart, and lungs. His anatomical drawings were revolutionary, to say the least, as he used transparent layers, perspective sections, and careful detailing to simplify complex visual details about the different parts of the body. These drawings would lay the foundation for all modern biological illustrations.
9. Compound Microscope
The first working model of a compound microscope was developed by the Dutch father-son duo Hans and Zacharias Janssen in the late 16th century. Their innovation involved placing lenses at both ends of a tube, creating a magnifying effect when looking through it. Although their early design laid the groundwork for future advancements, it offered a modest range of magnification, ranging from 3x to 9x, and produced images of mediocre quality.
By the late 1600s, improvements in lens technology improved both magnification and image quality, resulting in some breakthrough discoveries in the field of biology. For one example, German scientist Walther Flemming’s discovery of cell division in the late 1800s proved crucial for understanding biological processes like cancer growth. These early microscopes, though limited in their capabilities, paved the way for contemporary microscopy techniques, including super-resolution fluorescence microscopy, which had long-lasting implications in the treatment of diseases like Parkinson’s and Alzheimer’s.
8. Discovery Of Microorganisms
The discovery of microorganisms in the 17th century could be attributed to Robert Hooke and Antonie van Leeuwenhoek. Both of them made long-lasting contributions to our understanding of the microbial world between 1665 and 1678, recorded in publications by The Royal Society of London.
In his 1665 publication Micrographia, Robert Hooke made the first published description of a microorganism, particularly a microfungus that he got from a book’s red sheepskin cover covered in a mold. He also contributed towards the advancement of microscopy techniques, described in his preface to Micrographia.
Inspired by Hooke’s work, Leeuwenhoek began his own observations with a single-lens microscope almost a decade later. In his famous ‘letter on the Protozoa’, Leeuwenhoek gave detailed descriptions of protists and bacteria from a variety of environments.
Taxonomy is the science of classifying and naming living organisms. It was developed in the 18th century by Carl Linnaeus, often referred to as the Father of Taxonomy. His 1735 treatise, Systema Naturae, was the first work to detail a classification system that listed and organized every known plant and animal species at the time. This systematic approach introduced binomial nomenclature to the tree of life, with a method of assigning Latin names to the genus and species of every organism that we still use today.
Linnaeus’s taxonomy system revolutionized biology by providing a structured framework for organizing and naming the array of life on Earth. It also allowed clear communication among scientists worldwide, eliminating confusion caused by the use of lengthy and inconsistent species names specific to separate fields and regions of scientific study. Linnaeus is also known as one of the founders of modern ecology, as his work proved the interconnectedness of seemingly-different organisms in their natural environments.
6. Cell Theory
Even after the invention of the compound microscope, it would take another two centuries to develop a proper theory of living cells due to many factors. Some time around the 1830s, our understanding of cells and how they function was transformed by some important discoveries.
The first step was Robert Brown’s observation of the cell nucleus in 1833. Then there was the discovery of the cell’s nucleus in animal cells, followed by the discovery of the presence of a living material called protoplasm within all cells, particularly in plants.
The crucial breakthrough in cell theory happened in 1838, when botanist Matthias Jakob Schleiden and physiologist Theodor Schwann collaborated on the concept. Schwann extended the theory to include animals, bridging the gap between botany and zoology. Their pioneering work proved that cells are the fundamental building blocks of all organisms, plants and animals, and that some organisms are unicellular while others are multicellular. They were also the first scientists to identify the common components of cells as the cell membrane, nucleus, and cell body.
5. Darwin’s Theory Of Evolution
In his 1859 book, On the Origin of Species, Charles Darwin first described his theory of evolution by natural selection – a groundbreaking concept that would forever change the scientific field of biology and many others. This theory proposed that species evolve over time through the inheritance of physical or behavioral traits, driven by the concept of natural selection.
Darwin’s insight revolved around the idea that variations in traits exist within different living populations, such as the beak shape in Galapagos finches. Natural selection, as he argued, is the process through which individuals with advantageous traits for survival and reproduction are more likely to pass it onto the next generation, ultimately leading to the evolution of all species we see around us today.
Darwin’s theory, however, was incomplete without an understanding of the mechanism behind trait inheritance. He lacked knowledge about genetics, the role of genes in encoding traits, and the concept of genetic mutation as a source of variation. It would take many more years before that puzzle was solved by subsequent generations of evolutionary biologists.
The field of genetics traces its history back to the pioneering work of Gregor Mendel in the mid-19th century. Before his experiments, genetics was mostly theoretical. His experiments with pea plants not only expanded the scope of genetics to include experimental aspects, but also laid the foundation for many subsequent developments in the field. In a way, his work directly led to the complete mapping of the human genome with the Human Genome Project in the late 20th century.
Through experiments, Mendel formulated three fundamental principles of inheritance, detailing how traits are passed from one generation to the next. His discoveries were instrumental in explaining patterns of genetic inheritance, and its impact on biology has been profound. Genetic studies have revealed the molecular basis of inheritance, allowing us to decipher the genetic code and understand how genes encode traits in all living organisms.
3. Miller-Urey Experiment
In 1953, the Miller-Urey experiment conducted at the University of Chicago marked a pivotal moment in the study of abiogenesis, or the origin of life from non-living matter. The experiment aimed to replicate the conditions of Earth’s early atmosphere and oceans to investigate whether organic molecules, the building blocks of life, could emerge from purely inorganic chemical reactions.
Stanley Miller, under the supervision of Harold C. Urey, simulated the primitive Earth environment, which was then thought to have an atmosphere devoid of oxygen. The experiment successfully produced amino acids and various organic molecules fundamental to life. While the study had limitations and was later refined by other researchers with more accurate information on Earth’s early atmosphere, it began a phase of extensive research in prebiotic chemistry and the study of life’s emergence from non-life that continues till today.
While we still don’t know the exact origins of life on Earth, the Miller-Urey experiment proved that it could have happened through external energy sources, like lightning or UV radiation, interacting with basic, non-living constituents.
2. Stem Cells
The concept of stem cells was first proposed in the 19th century, initially in the context of the foundation of embryonic development. It wasn’t until the 1960s, however, that researchers identified and characterized stem cells within the bone marrow, particularly those responsible for producing various types of blood cells. This discovery laid the foundation for bone marrow transplants, initially introduced as a treatment for cancer and genetic blood disorders. Today, stem cells are integral to about 60,000 BMT procedures worldwide each year.
Further advances in stem cell research led to the identification of stem cells in human cord blood in 1978, and the cultivation of embryonic stem cells from mice a few years later. In the years since, stem cells have evolved from research tools for studying cell differentiation mechanisms to powerful resources for testing new medicines, reducing the need for animal testing. Cancer stem cells have since been regularly used to screen anti-tumor drugs, and stem cell therapy is currently under investigation in over 1,100 clinical studies.
1. Human Genome Project
The Human Genome Project began in 1990 as an international collaboration aimed at decoding the genetic blueprint of the human organism. Finished in 2003, the global effort successfully determined, documented, and publicly shared the sequences of nearly all the genetic content within the human genome, which we now know is made up of nearly three billion chemical base pairs.
While individual researchers had deciphered portions of human genes before this project, the majority of the genome had largely remained unexplored. A rough draft was announced by the team in 2000, followed by the project’s compilation in April, 2003 on the 50th anniversary of the discovery of DNA’s double-helix structure.
The Human Genome Project started a new phase in biological research, allowing scientists to study the genetic basis of diseases, develop targeted therapies, and further advance the field of personalized medicine.