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DARWINIAN EVOLUTION. Evolution can be simply defined as change over time, but it is more accurately defined as the change in allele frequencies in a population over time, where alleles are defined as alternative states of genes. Simple definition of evolution Application- evolution of TV.
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Evolution can be simply defined as change over time, but it is more accurately defined as the change in allele frequencies in a population over time, where alleles are defined as alternative states of genes
Both Plato's and Aristotle's views supported a static biodiversity Aristotle believed that organisms could be arranged on a scale of complexity (lesser to greater) called the scala naturae and that species are permanent, perfect, and non-evolving
The Judeo-Christian belief a divine creation of all species led to natural theology view
Paley’s most influential contribution to biological thought was his book Natural Theology: or, Evidences of the Existence and Attributes of the Deity, Collected from the Appearances of Nature, first published in 1802.Paley laid out a full exposition of natural theology, the belief that the nature of God could be understood by reference to His creation, the natural world. He introduced one of the most famous metaphors in the philosophy of science, the image of the watchmaker
Carolus Linnaeus He also used a system of grouping similar species into a hierarchy of increasingly general categories (species, genus, family etc.). However, Linneaus did not believe that resemblance implied kinship, instead he was an adherent of natural theology and that the similarities implied a pattern of their creation
George Cuvier noted that the deeper the fossils in the earth's layers or strata, the more dissimilar they were when compared to extant species. He acknowledged extinction, but was an opponent of any evolution. Instead he supported catastrophism and believed that such catastrophes (e.g., floods) were responsible for the extinctions
Frontispiece depicting the vertical section of the cavern at Gaylenreuth in Franconia, from George Cuvier's Essay on the Theory of the Earth (Edinburgh: William Blackwood, 1827)
James Hutton proposed that the Earth's features (e.g., canyons) could be explained by the theory of gradualism- big changes result from the cumulative effect of slow, current, continuous changes (e.g., valleys formed by the wearing action of water). Charles Lyell then incorporated gradualism into his theory of uniformitarianism-geological processes have not changed throughout the Earth's history.
Jean Baptiste Lamarck Theory involving two ideas: (1) use and disuse-the body parts that are used become larger and stronger and those that are not used atrophy and (2) evolution occurred by the inheritance of acquired characteristics.
Thomas Malthus wrote that human suffering was caused by the tendency for the population to increase faster than resources.
Darwin's evidence includes: The fossils of extinct species most closely resemble living ones occurring in the same geographic area. The pattern of fossils in the strata where progressive changes in characteristics can be seen in fossils of earlier and earlier layers.
Lands with similar climates have unrelated species, suggesting that diversity is not only influenced by climate and environment. The species of each continent are distinctive.
The species found on islands are more closely related to each other than they are to those on the mainland. But insular species do show strong affinities to those on the nearest continent.
Darwin's main ideas can be summarized as: 1. Natural selection is differential reproductive success or the unequal ability of an individual to survive and reproduce 2. Natural selection occurs due to the interaction between the environment and variation in the individuals within the population. 3. Natural selection results in the adaptation of populations of organisms to their environment.
Alfred Wallacehttp://www.age-of-the-sage.org/philosophy/wallace.html Alfred Russel Wallace (1823-1913)
Post-Darwinian Evidence for Evolution by Natural Selection 1. The fossil record continues to show increasing support for the evolution of species. 2. The Earth is much older than thought during Darwin's lifetime about 4.5 billion years old. 3. The discovery of the mechanism of heredity (DNA)
4. Structural or anatomical homologies (homologies are similarities between organisms that are due to genetic inheritance from a common ancestor) or the existence of similarities in more closely related organisms (comparative anatomy). 5. Developmental homologies or the existence of similarities in embryos of different species as well as the structures (e.g., tails and gill slits) that occur in human embryos.
6. The presence of vestigial structures (structures of marginal, in any, importance to the organism) such as ear wiggling muscles in humans, the appendix in humans, and the pelvic bones of cetaceans. 7. Studies in Molecular biology and the increased sequence homology between more closely related organisms.
8. More recent studies in biogeography (the study of the geographic distributions of species). 9. Current examples of evolution that have been documented include Kettlewell’s work with the peppered moth and antibiotic resistance in many bacterial species and viruses
Darwin was correct about the controversial nature of evolution. Objections to teaching evolution include: • Evolution has not been solidly demonstrated. Many critics say that evolution is just a theory but keep in mind that theories are comprehensive and are supported by an accumulation of extensive and varied evidence. B. Missing links are missing. Although in the past some gaps did exist in the vertebrate fossil record, these have now been filled in.
The Intelligent Design argument. The argument is that complex structures like the ear and eye could not have evolved by random processes, but there are “progressions” present throughout the animal phylogeny that suggest otherwise. • Evolution violates the Second Law of Thermodynamics. The Second Law of Thermodynamics states that during energy transformations, some or all of the energy is converted from more ordered forms to less ordered forms or entropy (disorder) increases. But this is applicable to energy dynamics and to closed systems. E. Natural Selection does not imply evolution. Evolution is a slow process taking millions of years and thus in our time frames we do not see the drastic changes (e.g., an amphibian evolving from a fish ancestor).
