New Core Curriculum Evolution Foundations of Scientific Process Using DNA to our Advantage Genetic Modification Introduction of new DNA sequences into an organism to alter the genetic makeup Introduces very specific characteristics Use enzymes to manipulate DNA Recombinant DNA - new form of DNA that is introduced Gene cloning splicing genes from a variety of species into a host cell Gene therapy inserting, deleting or manipulating genes in order to cure or lessen the effects of genetic diseases Sequencing Compare nucleotide sequences from different cells Analyze for similarities and differences PCR (polymerase chain reaction) copying selected segments of DNA Genetic fingerprinting Cloning Discussion Activity: GATTACA our future? Any living cell carries with it the experiences of a billion years of experimentation by its ancestor. - Max Delbruck, 1949 Evolution Change in frequency of genetically determined characteristics within a population over time Evolution Change in frequency of genetically determined characteristics within a population over time 1.Evolution occurs in populations of organisms of the same species 2.Genes (specific segments of DNA) determine the characteristics displayed by organisms 3.The mix of genes within a population can change Process that chooses/selects from the pool of variable DNA sequences those that are most adopted for the present environment and gives organisms possessing such a DNA a greater chance for survival is Natural Selection Natural selection encourages passage of beneficial genes to future generations and discourages harmful or less valuable genes DNA-based life is the product of natural selection. So are we. In a population, you will have variation in the DNA and the fittest members of the population will survive and pass on more efficiently their DNA. All species share a common ancestor and change due to the accumulation of very slight modifications and their sorting via Natural selection. There are two primary ways in which genetic diversity is generated within the population of a species: A)mutation (during semiconsdervative replication of DNA) and B)genetic recombination (during reproduction) ONE COPY TWO COPIES GACTGACT CTGACTGA GACTGACT CTGACTGA Sequence info is kept by separated strand GACTGACT CTGACTGA GACTGACT CTGACTGA EXACT COPY A) Semi-conservative Replication Provides opportunity for introduction and preservation of Novelty Mutation = any change in the genetic info (DNA) of an organism + mix of four subunit bases A C G T C T A G ONE COPY TWO COPIES GACTGACT CTGACTGA GACTGACT CTGACTGA + mix of four subunit bases A C G T C T A G Sequence info is kept by separated strand GACTGACT CTGACTGA GACTGACT CTGACTGA EXACT COPY A) Semi-conservative Replication To be important in the Evolution of organisms, mutations must be in cells that will become reproductive cells Mutation = any change in the genetic info (DNA) of an organism Reproduction (non-mutation) B) Genetic Recombination Genetic Diversity is Important for Natural Selection Evolution Change in frequency of genetically determined characteristics within a population over time How would you represent biological evolution? How do we know about those links? A closer look at the skeletal (bone) anatomy Cranium Limbs Different anatomies Opposum similar to Echidna : they are marsupials Echidna Raccoon Bear Opposum DNA sequences Brain Embryological Development Human Turnicate Sponge Species of organisms that are more closely related show greater similarity in their DNA than those that are distantly related DNA carries hereditary information: This fact has two main consequences: 1)one can trace the evolution of species through their similarities in DNA 2)the changes that can emerge along the way are constrained by the chemistry of DNA. Natural Selection Acts through DNA: Novel Species have Novel DNA Species: population of organisms that have the potential to interbreed naturally to produce fertile offspring, but do not interbreed with other groups non-fertile offsprings The logic behind Evolution Heritable : Capable of being passed from one generation to the next Variable: Different versions found among different individuals in the population DNA is the molecular basis for heritability and variability of traits! Individual organisms have traits. Traits are Evolution: change in frequency of inherited traits of a population from one generation to another, as governed by Natural Selection Some versions of DNA may prove advantageous for survival and efficient transfer of hereditary material. What is considered advantageous depends on ??? It is decided by ??? ENVIRONMENT NATURAL SELECTION