Some organisms don t display all characteristics all the time 1 1 Living Organisms Share Common Aspects of Structure Function Energy Flow INTRO All organisms descended from single celled ancestor that lived 4 billion yrs ago Single origin common ancestor Chapter 1 Principles of Life Thursday September 10 2015 11 41 AM Life had single origin Living organisms Composed of chem parts and similar structure Contain genetic info protein code Convert molecules Extract energy for life functions Replicate DNA Evolve Share structural similarities among set of genes Leads to common ancestry conclusion Viruses Not composed of cells can t carry out physiological functions Carry genetic info Mutate and evolve Depend on cells Major steps in history of life Earth formed b w 4 6 4 5 billion yrs ago 6 million yrs later 1st life rose from nonliving matter 2 billion after cell originated prokaryote Photosynthesis 2 7 billion yrs ago Nucleic acids critical step for evolution Reproduce themselves create large stable shapes proteins Cell Structure Membrane surrounded and enclosed complex proteins cell formed Fatty acids formed membrane like film Prokaryote single cell simple plasma membrane cyanobacteria confined to ocean shields from UV light Photosynthesis basis of life Early prokaryotes took small molecules from envt broke them down to release energy Led to abundance of O2 in atmosphere Aerobic metabolism uses O2 to release energy more efficient than anaerobic O2 accumulation resulted in ozone layer protects organisms not in water Cyanobacteria 1st photosynthetic organism Stromatolite contain ancient fossils live in low shallow water Eukaryotic cells Evolution of membrane enclosed compartments organelles specialized functions 1st organelles 2 5 billion yrs after 1st life Nucleus formation Endosymbiosis ingesting small cells formed organelles mutually beneficial Mitochondria chloroplasts have own DNA Chloroplasts can do photosynthesis 1 2 billion yrs after eukaryotes multicellularity Cellular specialization enabled multicellular eukaryotes to increase size become efficient at gathering resources living in specific envts Tracing evolutionary tree of life Organism reproduces by replicating genome all genetic DNA Estimated 21 000 genes Human Genome Project Gene section of DNA that codes for polypeptide 1 chromosome 1 molecule of DNA contains many genes Genomic equivalence every cell in body has exactly same DNA Only express certain genes in certain cells all cells have potential to be any cell Changes in replication mutation proteins change Beneficial mutations adaptations Discovering Species Linnaeus created binomial naming system Genus and species Latinized words In italics capital genus lowercase species underlined when written Phylogenetic tree document diagram evolutionary relationships as part of overarching tree of life Molecular data in 3 categories domains Archaea Bacteria Eukarya All evolved separately Archaea can live in extremes Unit 1 Page 1 Archaea can live in extremes Archaea and Bacteria single celled Eukarya plants animals fungi Protista Misnomer things are named but names don t make sense Ex seahorse starfish Generalized discovery Knowledge gained from one organism can be applied to other because common ancestor sharing genetic code similar molecular blocks Model organism 1 2 Life Depends on Organization and Energy Intro Energy required to maintain organization Organizational Hierarchy Atoms small molecules macromolecules proteins nucleic acids DNA cells cell specializations tissue cells performing common functions put together organs organ system multicellular organism All lvls of organization subject to 2nd law of thermodynamics Organism degrades unless energy applied Species pop communities interact w landscape biosphere earth landscape Systems Feedback system System analysis Set of interacting parts in which neither parts nor whole can be understood w taking into account interactions Consists of components processes by which components interact Composed of sys affect rate of earlier process in sys Positive feedback earlier processes sped up destabilizes explosive end childbirth Negative feedback slows down earlier processes stabilizes sys common in regulatory sys regulation Identify components of bio sys specify by which components interact Computational model 1 3 Genetic Systems Control the Flow Exchange Storage Use of Information Genomes encode proteins Nucleotide make up nucleic acid molecules Sequence of nucleotides in DNA allow organism to assemble protein Gene carries info for building 1 proteins proteins govern chem reaction in cell All cells same genome genomic equivalence Diff cells diff functions form diff proteins Express diff parts of genome Mutations affect nucleotide sequence protein encoding Genomes Effort to sequence human genome began in 1990 finished 13 yrs later Fewer genes than expected 21 000 genes code for protein Charles Darwin On the Origin of Species evo occurs through natural selection 1 4 Evolution Explains Diversity Evo change in genetic makeup of pop over time Natural selection Some organisms survive better than other Reproduces and pass adaptations Make organism suited for envt Artificial selection human imposed selection Practiced on crops domesticated animals Natural selection not human choice some individuals contribute more offspring to future gen Works through adaptation structural physiological behavioral Proximate explanation physiological genetic neurological developmental processes that explain how adaptation works Ultimate explanation comparison of variation w in among species describe how given trait affects organisms survival and repro rate Genetic Drift random changes in gene frequencies due to chance Unit 1 Page 2 Chapter 4 The Working Units of Life Thursday September 10 2015 1 17 PM 4 1 Cells Provide Compartments for Biochemical Reactions Intro Cells contain H2o and other small and large molecules 10 000 diff types of molecules in cells Used to transform matter and energy respond to envts and repro Impossible w cell enclosure Cell Theory 3 components Cells fundamental units of life All organisms composed of cells All cells come from preexisting cells 2 implications Studying cell bio studying life Life is continuous trace back to evo of cells Humans come from other humans Cell size Diameter from 1 100 micrometers Surface area to volume ratio As V increases SA increases V increases faster than SA Volume determines amt of metabolic