BIOL 120 1st Edition Lecture 2 Outline of Last Lecture I Introduction of Chapter II A Definition of science biology Criteria for living versus non living organisms III Fundamental Questions in Biology The Science of Life IV Hierarchy of living systems beginning A definition of Population Species Community Ecosystem Biosphere Outline of Current Lecture II Hierarchy of living systems finished III Process of science scientific method a Deductive reasoning Inductive reasoning observation hypothesis prediction IV Cells Cell Theory a Cell Theory Cell V Evolution and Natural Selection a Evolution Phylogenetic tree Natural selection fitness adaptation selective adaptation VI Interpreting the tree of life Taxonomy a Phylogenetic tree Taxonomy phylum genus species VII Summary of chapter 1 Current Lecture II Hierarchy of living systems finished a Interdependency among organisms i Living organism rely on each other for energy to survive 1 Trophic pyramid diagram from lecture 1 notes a Cycle repeats as decomposers provide nutrients from produces III Process of science scientific method 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 a Purpose of science is to understand the natural world through observations descriptions and reasoning b Science is not random it is a very precise process through observations and test c Scientific Enquiry i Deductive reasoning uses general principles to make specific predictions 1 i e I see green trees in BG therefore I believe that all the trees in BG have to be green ii Inductive reasoning uses specific observations to develop general conclusions 1 i e I see green trees in all parts of BG except for in the west therefore not all the trees in BG are green d Scientific Method i A systematic approach the understand the world around us ii Steps 1 Form a hypothesis a A possible explanation for an observation i Must be testable to be considered a good hypothesis ii If results are consistent with hypothesis then it is accepted if not then can adjust reject hypothesis then retest it 2 Form a prediction a A prediction provides a way to test the validity of a hypothesis b The more successful experiments the more valid the hypothesis i Always test a hypothesis with more than one experiment 3 Experiment a Used to test a hypothesis b Make sure the experiment is only testing one variable at a time by having a test experiment and a control experiment i i e temperature effect on the growth of plants only the temperature should be changed between the control and the experiment 4 Conclusion a Organize data and publish results 5 IV Cells Cell Theory a All organisms are made up of cells b Where do cells come from i Louis Pasteur conducted an experiment to prove that cells either form from each other or form spontaneously 1 Did so by having a flask sterilized containing nutrient broth and keeping one flask with it s neck still on and breaking the flask of the other a If the flask with the neck still attached began to have bacteria growing in it then cells were spontaneously formed b If the flask with the broken neck began to have bacteria growing in it then cells form from preexisting cells bacteria cells found in the air c Conclusion cells form from other cells 2 Created Cell Theory all organisms are made of cells and all cells come from preexisting cells a All single cell organisms are related by common ancestry b All multi cellular organism have descended from preexisting cells and are connected by common ancestry ii Cells 1 Cell a highly organized compartment bounded by a plasma membrane a Contains a concentration of chemicals floating in an aqueous solution b Is the basic unit of life 2 First cell was seen through a microscope in the late 1660s by Robert Hooke and Anton van Leeuwenhoek V Evolution and Natural Selection a Evolution a change in the characteristics of a population over time i Proposed by Darwin and Wallace in 1858 ii Shows that species are related to one another and can change over time iii Evolutionary changes occur throughout populations b Phylogenetic tree a graphical representation of the evolutionary relationships among species i A visual representation of evolutionary change over time displays either similarities or differences 1 i e all organisms have a common ancestry a 3 8 billion years ago prokaryotic simple cell organism was present 2 billion years ago eukaryotic complex organism began evolving from prokaryotic organisms c Natural Selection explains how evolution occurs i Effects individuals ii An individual s heritable traits can cause increased success in producing offspring making those traits more common in a population evolution is the result of natural selection iii Two conditions needed for natural selection to occur 1 Individuals in a population need a variety of heritable genes 2 Particular environments effect if an individual reproduces and passes on its genes or not iv Key terms 1 Fitness the ability of an individual to reproduce 2 Adaptation a trait that increases the fitness of an individual in a particular environment 3 Artificial selection repeating the selection process over generations results in changes in the characteristics of a domesticated population over time VI Interpreting the tree of life Taxonomy a Interpreting the Tree of Life i Can use molecular evidence to help understand as well 1 Compare an organism s genomes or proteins to get a more accurate connection between organisms 2 Compares the different types of DNA sequences to find relationships 3 Phylogenetic tree a branching diagram or tree showing the inferred evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical and genetic characteristics ii Tree of life indicates the three major group of organism 1 Eukarya 2 Bacteria 3 Arachaea b Taxonomy the effort to name and classify organisms also known as Binomial nomenclature i Used to specialize an animal s name on a worldwide basis 1 Created by Carolus Linnaeus in 1735 ii The groups are broken down into 1 Domain 2 Kingdom 3 Phylum a major lineage within a domain 4 Class 5 Order 6 Family 7 Genus made up of a closely related group of species 8 Species made up of individuals that regularly breed together or have characteristics that are distinct from other species a The organism s genus and species make up its scientific name genus is