Evolution Exam 1 Chapter 2 Theories of Creation o Theory of special creation Species do not change over time They were created independently of one another They were created recently o Theory of Descent with modification Species are not immutable but change over time Species are derived not independently but from a common or shared ancestor 2 1 Evidence of Change through Time o Evidence disproving the immutability of organisms Evidence from living species o Microevolution small scale changes in monitoring natural populations o Macroevolution by examining bodies of living organisms can view dramatic change Direct observation o Soapberry bugs data suggests that the soapberry bug populations evolved due to their new host evidence of microevolution the two sets of bugs were genetically different and therefore the short beaked bugs have descended with modification from the long beaked ancestors o Data documents the reduction in beak length that followed the introduction of the flat podded golden rain tree Characteristics of soapberry bugs are not immutable they have changed over time due to their environment Vestigial Organs o A vestigial structure is a useless or rudimentary version of a body part that has an important function in other closely allied species Ex A north island brown kiwi a flightless bird has tiny stubby wings Ex 2 a rubber boa has remnant hind limbs The interpretation is these species have descended with modification Humans too have vestigial structures i e a tailbone and goosebumps and the production of CMAH Evidence from the fossil record o A fossil is a trace of any organism that lived in the past o The total worldwide collection of fossils is considered the fossil record Fact of Extinction Law of Succession o The fact that many species have gone extinct suggests that Earth s flora and fauna have changed over time o The resemblance between living and fossil forms in the same region suggests that living organisms are descended with modification from earlier species Todays species are descended with modification from ancestors that lived in the same region it is to be expected that they would bear a stronger resemblance to their recent ancestors than to their more distantly related kin in other parts of the world Transitional Forms o Shows a mix of features between extinct animals and present day ones evidence for macroevolution 2 2 Evidence of Common Ancestry o Species are not independent but are connected by descent from a shared ancestor An introduction to Tree Thinking Evolutionary tree o Phylogenetic trees are a visual representation of descent with modification from a common ancestor o The groups that share a closer common ancestor are more closely related than they are to others The inventor of evolutionary trees was Charles Darwin o Ring Species one species can split into 2 Freely interbreeding populations connect the entire species but members of certain populations do not interbreed o Homology The study of likeness Structural and Developmental Homology o Homologous structures that are used for different functions but have the same sequence and arrangement of bones Developmental homologies embryos from different vertebrates show striking similarities early in development Molecular Homology all organisms inherited their genetic code from a common ancestor Processed psudogenes o o Small coding bits are exons separated by noncoding intervening sequences introns Introns get spliced out after being transcribed and before translation into mRNA o Retrotransposons reverse transcription to DNA and insertion at a new site Processed psuedogenes have no function but accumulate mutations the older one is the more mutations it will have o The earlier the ancestor in which a processed pseudogene appeared the more descendent species will have inherited it This is consistent with data p 58 Humans and Primates o Nonhomologus similarities in light of their function i e powerful tails and streamlined bodies of a shark and an orca whale Modern concept of Homology o Many biologists define homology as similarity due to the inheritance of traits from a common ancestor o Relationships among species Species that are extremely similar to one another tend to be clustered geographically This suggests that they were not created independently but are descended from a common ancestor that lived in the same area Galapagos Island a population expanded in the new habitat and that subpopulations subsequently colonized different islands in the group o Once mockingbird populations had become physically isolated from one another in this way they diverged enough to become distinct species o Uniformitarianism Hutton that geological processes taking place now operated similarly in the o Evidence of Common Ancestry 2 3 The Age of Earth past o Geologic Time Scale Proposed in opposition to catastrophism Younger rocks were deposited on top of older rocks Principle of superposition Lava and sedimentary rocks were originally laid down in horizontal postion Principle of original horizontality Rocks that intrude into seams in other rocks are younger than their host rocks principle of cross cutting relationships Boulders or other fragments found in a body of rock are older than their host rock principle of inclusions Earlier fossil forms are simpler than more recent forms and more recent forms are most similar to existing forms principle of faunal succession o Radiometric Dating Uses unstable isotopes of naturally occurring elements Isotopes decay meaning that they change into either different elements or different isotopes of the same element One half life is the amount of time it takes for 50 of the parent isotope 2 4 Is There Necessarily a Conflict between Evolutionary Biology and Religion present to decay into its daughter isotope o Methodological Naturalism To account for natural phenomena and the only explanations they accept are hypotheses and explanations that involve strictly natural causes o Ontological Naturalism Believes that nothing else exists apart from the natural world Chapter 3 Darwinian Natural Selection Both fossilized and living organisms were derived with modification from either a single common ancestor or a few 3 1 Artificial Selection Domestic Animals and Plants o To increase the frequency of desirable traits in their stocks plant and animal breeders employ artificial selection Darwin studied the method of evolution under domestication Breeders scrutinize their flocks and select