Chapter 1

Figure 1.24 Discovery Science zDiscovery science yDescribes natural structures and processes as accurately as possible through careful observation and analysis of data zData yAre recorded observations yCan be quantitative or qualitative

Hypothesis-Based Science zIn science, inquiry that asks specific questions yUsually involves the proposing and testing of hypothetical explanations, or hypotheses zIn science, a hypothesis yIs a tentative answer to a well-framed question, an explanation on trial yMakes predictions that can be tested

In this case study yMimicry in king snakes is examined yThe hypothesis predicts that predators in non–coral snake areas will attack king snakes more frequently than will predators that live where coral snakes are present Scarlet king snake Key Range of scarlet king snake Range of eastern color snake Eastern coral snake North Carolina South Carolina Figure 1.27

Field Experiments with Artificial Snakes zTo test this mimicry hypothesis yResearchers made hundreds of artificial snakes, an experimental group resembling king snakes and a control group of plain brown snakes (a) Artificial king snake (b) Brown artificial snake that has been attackedFigure 1.28

After a given period of time yThe researchers collected data that fit a key prediction Figure 1.29 In areas where coral snakes were present, most attacks were on artificial king snakes Key % of attacks on artificial king snakes % of attacks on brown artificial snakes Field site with artificial snakes 17% 83% North Carolina South Carolina X X X X X X X X X X X X X X In areas where coral snakes were absent, most attacks were on artificial king snakes 84% 16% Key

Limitations of Science zScience cannot address supernatural phenomena yBecause hypotheses must be testable and falsifiable and experimental results must be repeatable

Concept of Scale zThe study of life extends from the microscope scale of molecules and cells to the global scale of the entire living planet

Hierarchy of Organization zMolecule zOrganelle zCells zTissues zOrgan zOrganism zPopulation zCommunity zEcosystem

Feedback Regulation: Negative zAccumulation of an end product of a process slows that process zExample: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway

Feedback Regulation: Positive zAn end product speeds up its production zExample: blood clotting in response to injury

Grouping Species zTaxonomy (classifying life) yIs the branch of biology that names and classifies species according to a system of broader and broader groups Species Genus Family Order Class Phylum Kingdom Domain Mammalia Ursus ameri- canus (American black bear) Ursus Ursidae Carnivora Chordata Animalia Eukarya

The Three Domains of Life zAt the highest level, life is classified into three domains: yBacteria (prokaryotes) yArchaea (prokaryotes) yEukarya (eukaryotes) Eukaryotes include protists and the kingdoms Plantae, Fungi, and Animalia

LE 1-15 Bacteria 4 µm 100 µm 0.5 µm Kingdom Plantae Protists Kingdom Animalia Kingdom Fungi Archaea

Unifying Themes in Biology