BSC 2011 Spring 2013 Unit 3 Study Guide A Essentialism Idealism The ideas of essentialism were founded by Plato and 1 held the beliefs that God created all things and that all things have a constant perfect essence ideal form Essentialists strongly believed that species did not undergo any change Essentialism and idealism both shared the view that the earth was only several thousand years old b Natural Theology Natural Theologians were monotheistic western educated Christians during the 1600 s and 1700 s These individuals studied the natural world in order to understand God s plan They believed that species were divinely created as perfect all at once approximately 6000 years ago according to Genesis Carolus Linnaeus was a natural theologian who developed the classification system based on organism s similar appearances However in contrast to Darwin Linnaeus ascribes resemblances among species to a pattern of creation c Catastrophism The term catastrophism was developed by Georges Cuvier who was a natural theologian Cuvier believed that sporadic catastrophes caused the appearance and disappearance of organisms in the fossil record One example for this idea is that local floods would wipe out existing species and then neighboring species would proceed to move in no evolutionary changes d Uniformitarianism This is a term that was developed by Charles Lyell According to uniformitarianism mechanisms of change are constant over time The three main points of this definition are 1 Mechanisms of geologic change are constant uniform over time 2 The same processes are operating today as in the past and at the same rate uniform 3 Therefore the earth must be very old to have accumulated all the changes evident in the geological record 2 What is the biological definition of evolution Evolution can be defined as a change in the genetic composition of a population from generation to generation There are two subtypes of evolution microevolution and macroevolution Microevolution can be defined as the gradual evolution of traits within a population of a species over time However macroevolution is the evolution of an entirely new species Microevolution is a generally accepted theory but macroevolution causes many debates between scientists and creationists One main difference between these two views is that microevolution defines when a population evolves whereas macroevolution defines when an entirely new species evolves 3 How did the following support Darwin s idea that evolution could be a means by which life s diversity arose A Artificial Selection Artificial selection provided evidence of evolution because Darwin compared how humans selectively breed crops and animals for desirable traits A similar process occurs in nature where the individuals with more suitable traits have a higher chance of surviving and reproducing b Comparative Anatomy G Buffon a comparative anatomist suggested that species could be similar because they descended from a common ancestor He observed vertebrate forelimbs from humans cats and whales He stated that these species had the same kind of bones but that they later evolved different functions The definition for this discovery is homology which means similarity caused by shared ancestry c Geology Charles Lyell was a geologist who proposed the idea of geologic gradualism This idea explained that geological features were formed by slow gradual processes like erosion over long periods of time Note the difference between Hutton s idea and Cuvier s idea of catastrophism d Paleontology Paleontology is the study of fossils Cuvier played a large part in creating the idea of paleontology He observed that from one layer of stratum of rock to the next some new species appeared while others disappeared He inferred that extinctions must have been a common occurrence in the past This supported the idea of evolution but Cuvier staunchly opposed this idea e Comparative Embryology This field of study was used to observe that stages in development could be used to distinguish evolutionary relatedness As development proceeds similarity persists among more closely related vertebrates 4 a How can molecular biology provide evidence for evolution with examples Molecular biology is the study of sequencing protein and DNA amongst many other molecules In one study amino acids were studied in several different species and compared to the amino acid in a human hemoglobin polypeptide It supported the idea of evolution because the more recently two species had shared a common ancestor the more similar their proteins and DNA were 5 Distinguish between the following a Homologous Homology means similarity caused by shared ancestry Homologous structures share common ancestry but not necessarily similar function For an example humans cats and whales all have the same forearm bones and same relative position but different uses b Analogous Analogous structures share similar function but not common ancestry An insect and a bird both have wings for the same function flying but do not share a common ancestor c Vestigial Structures Vestigial structures are remnants of once functional ancestral structures An example of this are the vestigial hind limbs in whales and snakes that indicate a common ancestor but are no longer used 6 a What did Darwin find intriguing about the finches on the Galapagos Islands The finches that Darwin observed seemed to have different beak shapes and sizes relative to what kind of diet they had For example the large ground finch had a large beak that was better adapted for cracking seeds that fall to the ground b This observation of the finches helped to support Darwin s idea of natural selection by clearly displaying that the species was evolving in order to enhance their chances of survival 7 a Describe the process by which populations evolve via natural selection Some inferences that describe the process of evolution by natural selection are as follows 1 A struggle for existence occurs among organisms in a population 2 There is differential survival and reproduction among individuals in a population favoring advantageous traits 3 Natural selection gradually results in individuals with new adaptations that their ancestors did not have and could lead to a new species b Why is genetic variation a prerequisite for evolution by natural selection Without genetic variation the members of a species could only have traits that could possibly be harmful With variation however species are
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