BIOL 152 1st Edition Lecture 2 Outline of Last Lecture Gene Transcription and Translation Outline of Current Lecture Evolution Scientific theory that explains the origin of earth s species biodiversity by gradual change over time Descent with modification from common ancestor Is a principal unifying concept in biology Theory Is a comprehensive and well supported statement backed by large amounts of evidence Overview Evolution change in a population s allele frequency over time Natural Selection differential success in the survival and reproduction of different phenotypes resulting from the interaction of individuals with environment Evolutionary adaptation accumulation of inherited characteristics that enhance organism s ability to survive and reproduce A great resource http evolution berkeley edu evolibrary article evo 01 Aristotle 384 322 B C Created the Scala Naturae Stated that species are unchanging and arranged species on a ladder of increasing complexity with human being at the top of the ladder This was the principal model of biological thought until the 18th century The Scientific Community in the 1800s These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Carolus Linneaus created the taxonomy of species arranged by grouping similar species Highly known for creating the binomial nomenclature Defining Earth Georges Cuvier Used paleontology to define the mechanism of how Earth functions Stated the theory of Catastophism which states that the Earth had been affected in the past by violent events that led to extinctions and producing adaptive radiation James Hutton Used geology to define the mechanism of how Earth functions Stated the theory of Gadualism the cumulative effect of slow but continuous processes that have produced earth s geologic formations Charles Lyell Stated the theory of Uniformitarianism that same geologic processes that happened in the past are happening today at the same rate Darwin agreed and realized that if true the Earth was older than 6 000 years old which many thought it was during Darwin s time Theory of Evolution Jean Baptiste Lamarck Stated that evolutionary change is based upon two principles o Use and disuse o Inheritance of acquired characteristics Charles Darwin Went aboard the HMS Beagle Noticed how geologic change can be explained using fossil record Observed taxonomy that showed continental affinities and also showed similarities between extinct and living forms in the same locale Observed unique species groups on Galapagos Islands that were Endemic Observed the adaptation of organisms to the environment and the origin of new species Charles Darwin s Theory of Evolution Descent with Modification o All organisms are related through descent from a common ancestor that lived in the o remote past Over time descendants have accumulated modifications that allow them to survive and reproduce in specific habitats Deciphering the Theory of Natural Selection Ernst Mayr 1904 2005 an evolutionary biologist broke down Darwin s work into 4 observations and 2 inferences o Observation 1 individuals of a population vary extensively in their characteristics o Observation 2 traits are inherited from parent to offspring o Observation 3 all species have an ability to reproduce and population will increase o exponentially Observation 4 environmental resources are limited and as result populations tend to o be stable Inference 1 Individuals whose traits are best suited for survival are likely to leave more o offspring than less fit individuals Survival of the Fittest Inference 2 The unequal ability to survive and reproduce will lead to the gradual accumulation of favorable traits over generations Malthus 1766 1834 Human population growth is geometric exponential Growth kept in check by famine plagues and late marriage Summary of Natural Selection 1 Individuals do not evolve only populations do 2 Can only act on heritable traits 3 Environmental factors vary in space and time Observations of Evolution Direct Observation Drug resistance in bacteria and viruses o For example if antibiotics for a given bacteria is successful in eliminating bacteria there will always be a select few in the next generation that are resistant to the bacteria because of the parent being immune to the antibiotic Pesticide herbicide resistance in agriculture o For example if insecticides are used to kill mosquitoes then there will be a select few in the population that are resistant to the insecticide and those genes will then be passed onto the offspring which will remain immune to the insecticide Homologies Similar traits that arose from common ancestry Developmental observations o Ontogeny recapitulates phylogeny animals go through stages that seem to all resemble each other when organisms are going through successive embryonic stages This theory is discredited but it shows how evolutionarily organisms looked alike during o embryonic stages Genetic observation Evolution and Cancer 1 Variation due to mutations 2 Differential birth and death rates 3 Heredity Overview of Observations of Evolution 1 Direct Observations 2 Homologies 3 Fossil Record Current Lecture Evolution of Populations