BIOLOGICAL SCIENCE FIFTH EDITION Freeman Quillin Allison 1 Lecture Presentation by Cindy S. Malone, PhD, California State University Northridge
Roadmap 1 Key themes to structure your thinking about Biology starting with What does it mean to say that something is alive? 1.1 first including Two of the greatest unifying ideas in Biology The cell theory then The theory of evolution by natural selection 1.2 1.3 predicts The tree of life 1.4 including The process of doing Biology 1.5
All scientists ask questions that can be answered by measuring things by collecting data Science is about formulating hypotheses and finding evidence that supports or conflicts with those hypotheses For example, using carefully designed experiments, biologists test ideas about the way the natural world works by testing the predictions made by alternative hypotheses
Hypothesis testing is a two-step process: 1. State the hypothesis as precisely as possible and list the predictions it makes 2. Design an observational or experimental study that is capable of testing those predictions
Biologists practice evidencebased decision making Ask questions about how organisms work Pose hypotheses to answer those questions Use experimental or observational evidence to decide which hypotheses are correct
No experiments Based on observations Inductive reasoning general principles derived from large number of specific observations EXAMPLE: All living things are composed of cells 6
Involves carefully planned experiments Based on observations Deductive reasoning takes a general statement and extrapolates specific results we would expect
in this step includes personal observation as well as reading what is already published. Such pieces of information are sometimes referred as facts. - The question that follows is A hypothesis is a tentative, general statement based on observation. Hypothesis are tested by observation and/ or experimentation. I - New data is the product of observation and experimentation. The new data will either support or fail to support your hypothesis. A hypothesis can never be proven.
In designing an experiment several variables are defined: is the variable that is manipulated is the variable that will be measured. are kept constant throughout the experiment. The are groups that are subjected to manipulation The contains standard conditions, in which the independent variable is not manipulated. The control group usually approximates normal conditions.
Control Group Experimental Group
All living organisms share five fundamental characteristics: 1. All organisms acquire and use energy 2. All organisms are made up of membrane-bound cells 4. All organisms are capable of reproduction Populations of organisms are continually evolving All organisms process hereditary information encoded in genes as well as information from the environment
A is an explanation for a very general class of phenomena or observations that are supported by a wide body of evidence Theories have two components: Pattern Something that occurs in the natural world Process Responsible for creating the pattern
The cell is the fundamental structural unit in all living organisms All species are related by common ancestry and have changed over time in response to natural selection
In 1858, Charles Darwin and Alfred Russel Wallace made two claims regarding the natural world: All species are related by (pattern) Characteristics of species can be modified from generation to generation (process) : It is a change in the characteristics of a population over time It means that species are related to one another and can change through time explains how evolution occurs
A is A group of individuals of the same species Living in the same area At the same time Two conditions must be met to occur for in a population: 1. Individuals must vary in characteristics that are heritable 2. In a particular environment, certain versions of these heritable traits help individuals reproduce more than do other versions
The cell theory and the theory of evolution by natural selection Imply that all species come from preexisting species And that all species, past and present, trace their ancestry back to a is A divergence process in which natural selection has caused populations of one species to diverge to form new species
The is A family tree of organisms that describes the genealogical relationships among species with a single ancestral species at its base is The actual genealogical relationships among all organisms
This node represents the common ancestor of all organisms alive today DOMAIN BACTERIA Mycoplasma Firmicutes Cyanobacteria Actinobacteria Spirochaetes Chlamydiae Bacteriodetes -Proteobacteria -Proteobacteria -Proteobacteria -Proteobacteria -Proteobacteria DOMAIN ARCHAEA Thaumarchaeota Crenarchaeota Korarchaeota This node Euryarchaeota represents the common ancestor of archaea and DOMAIN EUKARYA eukaryotes Slime molds Fungi Animals Choanoflagellates Euglenids Parabasilids Diplomonads Red algae Green algae Land plants Foraminiferans Ciliates Dinoflagellates Apicomplexans Water molds Diatoms Fungi, animals, and plants are small branch tips on the tree of life A Is used to show the relationships between species Branches that share a recent common ancestor represent species that are closely related Branches that do not share recent common ancestors represent species that are more distantly related Brown algae
The tree of life indicates three major groups of organisms: The (a) Eukaryotic cells have a membrane-bound nucleus. Membrane around nucleus Nucleus Two groups of and (b) Prokaryotic cells do not have a membrane-bound nucleus. 1 m No nucleus 0.1 m
is the effort to name and classify organisms A is a named group Woese created this new taxonomic level It consists of three taxa: Bacteria Archaea Eukarya A is a major lineage within a domain
In 1735 Carolus Linnaeus established the classification system still in use today Each organism is given a unique two-part scientific name It consists of the and the A is Made up of a closely related group of species A is made up of Individuals that regularly breed together Or individuals whose characteristics are distinct from those of other species