Early Evolutionists and the Fixity of Species

Biological Evolution and Early Human Evidence ANTH 2301 Early Evolutionists and the Fixity of Species Evolution is the definition of a change in allele frequency within a gene pool that over time may result in modifications to the morphology (form and structure) of an organism. The concepts of natural selection, speciation, and mutation are all related to evolution and will be covered in later sections. The dominant belief in Western thought before to the 19th century was that nature was static and permanent, created by a supreme creator in its existing form, and it never changed. The vast chain of being, a fixed natural system in which all living things were placed in a predetermined order said to have been ordained by God, existed. God was at the apex of this hierarchy, followed by angels, and last, humanity. Animals of all kinds came next to humans, then plants and minerals. This hierarchy distinguished humans from the rest of the animal kingdom and gave certain species a higher status than others, which made it important. Between the fourteenth and eighteenth centuries, there was a shift in popular perception regarding the natural world. Some people started to wonder if it was really so static. The first person in the West to assert that nature has changed throughout time and that these changes are still observable is the British scientist and architect Robert Hooke. According to his theory, fossils are the genuine remnants of extinct plants and animals. The previously held belief that fossils were merely pictures of stones was contradicted by this finding. In addition, Hooke observed that numerous marine fossils were found far from any ocean that was known to exist. This led him to the then-revolutionary conclusion that Earth's physical characteristics and geography had undergone significant alteration. French biologist Jean-Baptiste Lamarck, who is most remembered for having created the first theory of macroevolution—a theory regarding how the actual transition from one species into another may take place—was the first to suggest a method by which species could change. The nowdisproved notion of the inheritance of acquired features served as the foundation for Lamarck's hypothesis. According to Lamarck, an organ's or trait's use might be determined by looking at its size or complexity. Specifically, he thought that an organ's utility might be determined by its size and a trait's utility by its intricacy. According to his theory, features and organs that aid in a creature's survival would get larger and more complex over time, whereas less useful features will shrink and become simpler until going extinct. The elongated neck of a giraffe is his go-to illustration of this idea in action. According to Lamarck's theory, giraffes' longer necks are a result of their stretching them to reach the leaves at the top of trees, and these longer necks are passed on to the next generation. Lamarckian inheritance is another name for this notion of learned feature inheritance. Lamarck thought wants, wills, wishes, and aspirations were all enough to drive change, which is an intriguing aspect of his philosophy. That is, hoping for or wanting a change in one's physical attributes has the power to bring about that transformation. Lamarckian inheritance is problematic in two main ways. First, without a conscious behavioural shift, needs, wants, and desires do not translate into changes in physical attributes. Even if someone wishes they had blue hair, colouring won't make their hair that colour. The inability to pass on learned features via heredity is the second issue. Children would not inherit blue hair if someone coloured their own hair blue. Characteristics that an individual acquires over their lifetime are not transferred to offspring. Lamarck's hypothesis of macroevolution is not unimportant, even if it is not accurate. Lamarck was the first to suggest a method by which evolutionary change from one species into another might really occur. He also recognised the significance of interactions between organisms and their surroundings in the evolutionary process. Another Frenchman who was a prominent scientist in the early 19th century, Georges Cuvier, made several contributions to the theory of evolution. His idea of catastrophism, which he created to explain the growing quantity of fossils being discovered—some of which showed imprints of extinct creatures—is what made him most famous. According to the notion of catastrophism, natural calamities such as earthquakes, floods, and other floods—which are seen as divine acts—are to blame for the extinction of all creatures in certain locations at specific periods. Cuvier said that either whole new species had emerged or animals from nearby regions had moved in to repopulate the places. Cuvier suggested that newly evolved species with a more contemporary look were the product of a more recent creation event in order to be compatible with newly discovered fossil evidence showing that organisms had gotten more complicated throughout time. Even if scientists no longer support catastrophism as a workable hypothesis, Cuvier's notion of extinction is nevertheless a key element of modern evolutionary theory. The originator of modern geology, Scottish geologist Charles Lyell, made significant contributions to the evolutionary theory as well. In his three-volume work Principles of Geology (1830–1833), he made the case that geological processes that occur now are the same as those that did in the past. The current geological landscape was created by these processes, including wind and rain. These mostly slow-moving geological processes produced rivers, lakes, and mountains. The uniformitarianism principle is the name given to this hypothesis. Lyell proposed that Earth must be considerably older than previously thought in order for such slow-acting forces to cause significant change. The majority of natural historians had the belief that the planet was less than 6,000 years old before Lyell's publication. These estimates were derived from calculations based on the Old Testament. Lyell altered the framework that scientists used to interpret the geological past when he revised the estimated age of the world from few thousand years to millions of years.