Nature of Science and Measurement What is Science The investigation of rational concepts through observation and experimentation Pseudoscience Astrology Independent Variables what the experimenter changes x axis Dependent Variables What is measured y axis Categorical variables that can be grouped into categories species age group male vs female Continuous range of values time Boxed Graphs outliers helps when you have repeated values Accuracy Measure of bias how close to the truth Systematic Error Consistently off target by the same amount Precision Measure of spread repeatable data Random Error reproducibility error data spread out Descriptive Statistics no significance Ratio Average sum of all numbers divided by the total amount of pieces of data Mode Appears the most Median Middle number when put in numerical order Range Highest number lowest number Inferential Statistics allows biologist to statistically test for differences between two populations using probability theory and algebra T test comparing two sets of data ratio of differences between means and standard deviation 1 write your null 2 calculate t statistic 3 find critical value Critical Value chart with degrees of freedom and p value 4 compare t statistic to critical value t stat right of C V reject the null t stat left of C V fail to reject the null P values 05 reject Null significant difference 05 fail to reject null no significant difference Variance Quantifies the shape of the distribution square variance Standard Deviation square root of variance how far the number differs from the average Degrees of Freedom total sample size of treatments Development Genetics Olvedo Allometry the study of the relationship of body size to shape anatomy physiology and finally behavior ability to regulate growth of different limbs This is done by CTO cintillo positive cells The result of the paper is that planarians do obey allometry with their CTO cells Mendelian Explanations TH Morgan Two main concepts within the paper are blending inheritance and particulate inheritance Blending inheritance characters are inherited in heterozygous individuals that show the effects of both alleles and incomplete dominance Particulate inheritance inheritance of discrete characters via genes that are independently expressed without the blending of characters from one generation to the next What are the actual factors associated with this paper 1 Sex linked traits 2 Allelles genes are physically on chromosomes Sex Limited Inheritance in Drosophilia This paper is a discussion of Punnett squares and how to arrange them Morgan found that alleles are on a physical place on the chromosome and sometimes they can even be on a sex chromosome X Regeneration of Planaria Alvarado Planarians have the ability to regenerate after losing a body part Neo blasts are proposed mechanisms of regenerations Chi squares statistical test In the formula the things that you compare are the observed and expected values frequency Null there is no difference between the expected and absence It is used for categorical data You have to have an expected value You need to have a model to get an expected value An example of a model you can use is Punnett square Calculate your chi square value then find you critical value You find this by your degrees of freedom Df of categories minus 1 p 05 Find your degrees of freedom and you p value then drag your finger over Once you have this you compare your critical value to your chi square To the left of the C V is fail to reject and to the right of the C V is reject Picture the graph if you are on the tail or not on the tail visually If chi square is greater than the critical value you reject the null which means your p is less than 0 05 If chi square is less than the critical value you fail to reject the null which means your p is greater than 0 05 If there is no difference then that means it is a good model There is no difference between expected and observed Punnet Squares Autosomal r R RR Rr Rr rr R r Sex linked XB XBXb XBXB Y XbY XBY Xb XB physical location of a gene e g ap apterous locus having two copies of the same allele e g ap ap Terms Locus Allele version variant of a gene ap ap Genotype combination of alleles at one or more loci Phenotype Trait morphology behavior molecule etc Homozygous Heterozygous having two different alleles at a locus e g ap ap Dominant an allele whose phenotype is expressed in a heterozygote e g ap ap flies have normal wings Recessive an allele whose phenotype is not expressed in a recessive Wild Type Individuals in a populations the typical phenotype for a given trait Isometic scaling proportional across time Allometic different body parts grow at different proportions Categorical Data variables you can group into categories Continuous Data none desecrate categories heterozgyote ap is Meiosis Mendel s Laws Law of segregation The two copies of gene segregate or separate from each other during transmission from parent to offspring Law of independent assortment Two different genes will randomly assort their alleles during the formation of haploid cell Drosophila Short generation time only 2 weeks Cheap and easy maintenance Very well known genetics 100 years of study Huge availability of genetic tools geneticist Swiss Army Many homologous genes with vertebrates Small animal but with a complex phenotype Statistical Analysis Descriptive statistics e g describe a set of data by their mean and SD Inferential statistics e g Hypothesis testing Evolution Evolution Descent with modification or Changes in allele frequency Pattern What has happened Process How did it happen Types of Evolution Natural Selection Differential success in reproduction of different phenotypes resulting from the interaction of organisms with their environment Sexual Selection Selection caused by differences among phenotypes in mating success 3 things you need for selection 1 Variable Your population has to have different traits 2 Heritable your traits have to be able to be inherited from parents DNA 3 Selective some organisms have to be better at surviving and reproducing than others Gene Flow Process of evolution in which individuals migrate from one population to another resulting in changes in allele frequencies Gene flow often inhibits other processes of evolution Genetic Drift Process of evolution in which allele frequencies change due to random drift and chance events Genetic drift is a non adaptive process and occurs more commonly in
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