Animal Behavior - Biology 420/543 |
Bowling Green State University, Fall 2008 |
"Science can purify religion from error and superstition. Religion can purify science from idolatry and false absolutes" -- Pope John Paul II (Karol Wojtyla) (1920 - soon) b. Wadowice, Poland
Most religions, including christianity or islam, are "creationist" in their fundamental tenant. They hold that the material world around us, along with all life inhabiting it, has come about by the work of god. In the middle ages, creation applied to the physical world, life, and the soul at a fairly broad and rather non-specific level. A narrowing of the term only became established at a time when scientific discoveries of physical laws, understanding of natural history, and recognition of the stunning diversity of species across the continents became apparent. An increasingly literal interpretation of the bible only became established in the 17th and 18th century. Leading thinkers of the time more narrowly interpretated the book of genesis to mean that god created the entire diversity, a breeding pair of each and every species now inhabiting the earth.
Throughout time official church doctrine had adopted distinct claims about the world in which we live. Few of such claims are actually recognized in the bible itself. Notably, scriptures were not written nor ever claim to be scientific texts, and are surprisingly vague when it comes to actual claims for the material realm. These narrowed views however, as in the case of creation, often arose much later at the pen of influential leaders and thinkers. Scientific discovery promptly proceeded to falsify a variety of some of the more absurd claims about the world, including its shape as a flat disk, its position at the center of the universe, or its age.
The diversity of species on earth provided a particular challenge. <Taxonomy>: aims to classify all living things into hierarchical groups based on morphological similarities (e.g., birds with other birds, bats with other bats, and whales with other sea mammals) without regard how they got there. Such species diversity was viewed by many taxonomists as a sign of gods creation and with their work they wished to celebrate the creator's work through documenting this diversity and by assigning all living things into categories.
The view that god had deliberately created each species individually was challenged by the view that god's work may have instead setup all the basic mechanisms, which subsequently gave rise to the current diversity of species. <Phylogeny> (i.e., Systematics): attempts to explain the reasons behind similarities and dissimilarities of life forms via <Evolution>: a processes by which living things first appeared on earth and have since expanded into present-day diversity as a result of <Speciation> (i.e., cladogenesis). It views the current diversity of species as the result of continual change to ancestoral populations over long periods of time. Central are processes by which the characteristics of living organisms change over many generations as traits are passed from one generation to the next. Specifically, evolution aims to elucidate how living things first appeared on earth and how they have since diversified and changed. The term evolution and phylogenetic thinking were well established when Darwin appeared on the scene. Thus he did not pioneer the field of evolution, his main contribution is for proposing <Natural selection> as its mechanism. In his view, evolution involved changes in inherited characteristics over time, which ultimately result in behavioral and phenotypic diversification of populations. The origin and ancestral succession constituting the evolutionary descent of a species, or class of species. It traces the evolutionary origins and transformations by identifying <Homology>. Homologies are a resemblance in body form or behavior in different animals as a consequence of common ancestry: e.g. human and whale front limb. In contrast, <Analogy> refers to a resemblance in body form or behavior in different animals as a consequence of independent adaptation to the same or similar environmental conditions and not due to common ancestry: e.g. echolocation in birds, bats and dolphins.
<Anagenesis>: Evolutionary process for linear descent where a species evolves into another without any splitting of the phylogenetic tree. It involves changes in traits for a species over time (i.e., microevolution).<Cladogenesis>: changes in traits over time that lead to the formation of new species (i.e., macroevolution)
Following the first world war with the adoption of Darwinism by Germany's Nazi leaders, William Jennings Bryan, a famous lawyer and populist, mounted an anti-evolutionist campaign. He was concerned that Darwinism was an insult to American morality and suggested that schools not teach evolution or mention the struggle for existence that is implicit in it. This lead to the Scopes Trial.
<Phylogeny>: attempts to explain the reasons behind similarities/dissimilarities of life forms through
Biological Species Concept uses reproductive continuity as its primary criterion.
<Speciation>: Phylogenetic split in a group of related individuals to the point where they become different enough to be considered separate species (e.g., unable to produce viable offspring). It refers to the development of a genetic discontinuity between groups of individuals
Speciation and the emergence of Major Lineages (Phyla):
Case Study: Cichlids of the African Great Lakes: Lakes Victoria, Tanganyika, Malawi
Are human populations subject to natural selection? Are we changing? What are the odds that we will undergo speciation?