Zoology

• 1. Ancient Foundations And Origins

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  Cave paintings in France dating back 15,000 years show bison, horses, and deer rendered with careful detail. Prehistoric people studied animals to exploit them and survive their environment. The Neolithic Revolution brought the domestication of animals throughout Antiquity. Ancient knowledge appears in realistic depictions from the Near East, Mesopotamia, and Egypt. Egyptian hieroglyphics included images of animals alongside husbandry practices and hunting techniques. Aristotle viewed animals as living organisms in the fourth century BC. He spent two years on Lesbos observing plants and animals. He divided creatures into groups with blood and without blood. Roman physician Galen dissected animals four hundred years later because human dissection was prohibited. His conclusions sometimes proved false yet remained unchallenged for centuries.

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• 2. Renaissance Revolution And Discovery

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  Conrad Gessner published a 4,500-page encyclopedia between 1551 and 1558 that marked the beginning of modern zoology. Albertus Magnus wrote commentaries on all of Aristotle's works during the post-classical era. Andreas Vesalius and William Harvey used experimentation and observation in physiology during the 16th century. Antonie van Leeuwenhoek revealed the previously unknown world of microorganisms through microscopy. Robert Hooke endorsed these observations stating all living organisms composed one or more cells. Carl Linnaeus began to classify the diversity of life and fossil records. Jean-Baptiste Lamarck studied development and behavior of organisms. Buffon contributed to the study of natural history during this period. Naturalists rejected essentialism and considered extinction and species mutability over the 18th, 19th and 20th centuries.

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• 3. Evolutionary Theory And Modern Synthesis

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  Charles Darwin published his theory of evolution by natural selection in 1859. The publication placed organic evolution on a new footing with observational evidence. Gregor Mendel began work on peas in 1865 establishing the basis for modern genetics. The rediscovery of Mendel's work led to rapid development of genetics in the early 20th century. Population genetics combined with natural selection created evolutionary biology by the 1930s. Alexander von Humboldt investigated interactions between organisms and their environment. His work laid foundations for biogeography, ecology and ethology. Alfred Russel Wallace had some work jointly published with Charles Darwin. The end of the 19th century saw the fall of spontaneous generation and rise of germ theory.

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• 4. Molecular Biology And Genetic Breakthroughs

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  Francis Crick and James Watson determined the double helical structure of DNA in 1953. Rosalind Franklin contributed to this discovery alongside them. This event opened up the realm of molecular biology leading to advances in cell biology. Developmental biology re-entered evolutionary biology from its initial exclusion through the study of evolutionary developmental biology in the 1980s. DNA sequencing elucidated degrees of affinity between different organisms during the late 20th century. Bioinformatics and computational biology techniques became common tools for researchers. Molecular genetics emerged as a prominent sub-field since the early 2000s. Scientists use computer science methods to infer historical attributes of populations or species.

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• 5. Taxonomy And Systematic Classification

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  Carl Linnaeus grouped species according to shared physical characteristics in his first edition of Systema Naturae published in 1735. Modern biological classification generally starts with the three-domain system including Archaea, Bacteria and Eukaryota. These domains reflect whether cells have nuclei and differences in chemical composition of cell exteriors. The scientific name of an organism generates from its genus and species. Humans are listed as Homo sapiens where Homo is the genus and sapiens the specific epithet. The International Code of Zoological Nomenclature administers the classification and taxonomy of zoological organisms. A merging draft called BioCode was published in 1997 but has yet to be formally adopted. Five-kingdom systems now appear outdated to many scientists.

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• 6. Specialized Disciplines And Branches

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  Ethology studies animal behavior under natural conditions as opposed to laboratory settings. Charles Darwin wrote The Expression of the Emotions in Man and Animals influencing future ethologists. Nikolaas Tinbergen formulated four questions regarding proximate causes and survival value of behavior. Biogeography focuses on dispersal, migration, plate tectonics and climate change topics. Alfred Russel Wallace originated this field of study alongside Charles Darwin. Physiology examines mechanical, physical and biochemical processes of living organisms by understanding how structures function as a whole. Developmental biology includes embryonic development, cellular differentiation and regeneration processes. Vertebrate zoology covers animals with backbones such as fish, amphibians, reptiles, birds and mammals. Invertebrate zoology deals with sponges, echinoderms, worms, molluscs and arthropods.

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