welcome to ap daily this is mr burris from union high school in vancouver washington today's topic is 7.6 evidence for evolution so what will we be learning today for today's lesson we're going to look at what evidence supports evolution how are fossils dated how do morphological homologies provide evidence for common ancestry how do fundamental molecular and cellular features shared across all domains of life provide evidence of common ancestry and then finally what evidence supports relatedness of organisms in all domains so let's dive in evolution is supported by scientific evidence molecular morphological and genetic evidence from extant and extinct organisms adds to our understanding of evolution evidence supporting evolution includes the following geographical this is evidence based on characteristics of a habitat or land area there is geological which is evidence based on environmental features of the earth over time fossils document patterns of evolution and changes in environmental conditions over time there's physical which is evidence based on phenotypes of species there's biochemical which is evidence based on chemical composition of living things so basically comparison of biomolecules such as dna and proteins and then finally mathematical evidence based on calculations and statistics mathematical models and simulations are used to illustrate and support evolution fossils are the preserved remains impression or trace of once living organisms from the past fossils can be dated using a variety of methods you can use the age of rocks where a fossil is found the rate of decay of isotopes including carbon 14 and geographical data while fossil records are incomplete they provide information about earth's history and the living world that existed at that time morphological homologies represent modified traits shared among different species homologous structures are a variation and structure that was present in a common ancestor for example the bone structure of human arms cat legs horse legs bat wings and dolphin fins as you can see on the screen vestigial structures have a reduced or obsolete feature that serve little or no purpose for the organism example the bone structure for legs and some snakes the hip bone structures and whales and the human tailbone analogous structures are structures that evolved independently in different species due to similar environmental conditions selective pressures biochemical evidence is a comparison of dna nucleotide sequences and or protein amino acid sequences this provides evidence since all living organisms share the same or highly similar genetic code the same or highly similar process of gene expression and the same genetic language the table on the bottom here is about the divergence and percent of mitochondria dna sequences among five primates the more amino acid differences among the five different mammals the more time that has passed since their divergence the human and chimpanzee diverged more recently in comparison to the human and given based on the mitochondria differences many fundamental molecular and cellular features and processes are conserved structural and functional evidence supports the relatedness of organisms in all domains dna and rna are carriers of genetic information through transcription translation and replication major features of the genetic code are shared by all modern living systems and finally the metabolic pathways in order to produce atp are conserved across all currently recognized domains for example glycolysis so let's do some practice for today's practice you're going to be describing the data from a table or graph including identifying specific data points for this question what i would like you to do is pause your video read the question analyze the data table and formulate your answer when you're ready push play welcome back for this question you were looking at what evidence would best account for the difference in the primary nitrogenous waste products of tadpoles and frogs your answer should have been b differences in the biochemical process occurring in frog cells and tadpole cells so what should you take away from today's lesson first molecular morphological and genetic evidence from extant and extinct organisms add to the understanding of evolution fossils can be dated by a variety of methods to provide evidence for evolution for example relative and radioactive dating techniques morphological homologies provide evidence of shared common ancestry many fundamental molecular and cellular features and processes are conserved across organisms for example similar genetic codes and processes that synthesize atp and finally structural and function evidence supports relatedness of organisms in all domains well i hope today's lesson was helpful until next time thank you