EBIO 1220 1nd EditionExam # 1 Study Guide Lectures: 1 - 7Lecture 1 (January 15)Charles Darwin revolutionized science with his discoveries on his voyage on the HMS Beagle. This revolution is called the Darwinian Revolution. Before Darwin, the earth was believed to be young and unchanging. The belief was that all species had remained the same since creation and that there was no such thing as a “new” species. Darwin’s observations, especially in the Galapagos Islands completely contradicted this traditional view and his theories were published in On the Origin of Species in 1859. His findings focused on three main ideas.I. Descent with Modification: species evolve and change over time and derive from a common ancestorII. Adaptations: characteristics that enhance organism’s survival and ability to reproduce in a specific environmentIII. Evolution: change in genetic composition of species over time, such that species alive today are descendants of ancestral speciesEvolution is a fact! The following are proof that evolution is fact.IV. Modern organisms differ from recent fossil organismsV. Many modern forms not present in early fossil recordsVI. Pathogens change from antibiotic susceptible to antibiotic resistantVII. Species have gone extinct in our lifetimesEvolution works through a mechanism called natural selection. Natural Selection is an evolutionary process in which individuals with certain heritable traits are more likely to survive and reproduce, therefore leaving more offspring with these traits. At the time that Darwin cameup with this theory, he had no idea about genes but hypothesized some sort of heritable aspect.Key ingredients for Natural Selection are as follows:a. Individuals w/in a species varyb. Some of these variations are heritablec. More offspring are produced than can survived. Survival and reproduction are non-randome. Traits that confer survival and reproductive advantages will increase in frequency in the populationLecture 2 (January 20)Evolution comes from natural selection and genetic drift. Natural Selection is defined in lecture one and is nonrandom. Genetic drift is the random fixation or loss of alleles in small populationsand is random. These two mechanisms do not CREATE variation, but rather they simply preserveor eliminate variation. Variants favored by selection depend on the environment. Selection doesn’t have any “long-term” goals. It does not favor positive outcomes such as intelligence, complexity, longevity or ethical behavior. Selection favors what is most successful in that specificenvironment at that specific time. Traits are favored if they increase survival and reproductive output.Evolution is defined as genetic change over time and is a fact. Natural Selection is a theory that helps explain evolution.Lecture 3 (January 22)The word, species, comes from the Latin word meaning “appearance” or “kind.” Speciation is process by which one population splits into two or more separate species. Species are defined using lots of types of data:II. Morphology- color, body shape, size, etc.III. PhysiologyIV. BiochemistryV. DNA SequencesThe biological species concept states that a species is a group of populations whose members have the potential to interbreed in nature can create viable, fertile offspring. This is the most widely used species concept. This concept is limited when it comes to organisms that reproduceasexually. The morphological species concept states that a species is defined through its morphology. Morphology is the study of shape and has to do with any characteristic of appearance. This species concept is limited because appearance can be deceiving, because often members of different species can look alike physically. Also, Males and females of the same species sometimes have drastically different appearances. The ecological species concept states that a species is defined in terms of its environment. Features of ecology are important in determining species. The phylogenetic species concept defines a species as the smallest group of individuals in a phylogenetic tree. These species are clustered by genetic and morphological data.Biological factors and barriers can impede two groups from producing fertile, viable offspring. This creates reproductive isolation. Pre-zygotic barriers are factors that impede reproduction before fertilization. Post-zygotic barriers are factors that impede reproduction after fertilization. Hybrids are a cross between two species. Reproductive isolation causes isolated populations to diverge and adapt to different environments. When the barriers disappear there are three possible outcomes:II. Reinforcement: the two populations can no longer interbreed, hybrids are not viable andthe two become separate species, 2 species totalIII. Fusion: the two populations readily interbreed and fuse back into the same species, 1 species totalIV. Stability: hybrids are viable and fertile and become their own separate species, 3 speciestotalGene Flow is genetic info from one population exchanged with another. There are many barriersto gene flow: a. Human structuresb. Changes in geologyc. Natural disastersLecture 4 (January 27)Pre-zygotic isolating mechanisms inhibit mating between two species before an egg can be fertilized. These include:a. Temporal: Closely related populations find mates at different times of the yearb. Behavioral: Closely related populations use different mating ritualsc. Mechanical: Closely related populations try to mate but it doesn’t workd. Gametic: Cell surface proteins on eggs don’t respond to sperm from a closely related population and a zygote is not formedPost-zygotic isolation mechanisms inhibit reproduction between two species after fertilization. These include:a. Reduced Hybrid Viability: offspring are only viable for a few days at most and are sicklyb. Reduced Hybrid Fertility: hybrids are viable but sterile and the hybrid population does not lastc. Hybrid Breakdown: offspring are viable and fertile in the first generation but overtime the become inviable and/or infertileAllopatric speciation occurs when two populations are geographically isolated and, in turn, adapt and evolve separately. In allopatric speciation there is no gene flow between the closely related populations. The new populations evolve independently by mutation, selection, and genetic drift.Sympiatric speciation occurs when new species form without geographic isolation. This is much more rare