Albia Dugger • Miami Dade College

Cecie StarrChristine EversLisa Starr

www.cengage.com/biology/starr

Chapter 1Invitation to Biology

(Sections 1.5 - 1.9)

1.5 Organizing Species Information

• Each type of organism has a unique, two-part name• The first part is the genus name• When combined with the specific epithet, it designates a

particular species

• Linnaean taxonomy (Carolus Linnaeus) sorts all species into taxa on the basis of shared traits

Key Terms

• species • A type of organism

• genus • A group of species that share a unique set of traits; also

the first part of a species name

• specific epithet • Second part of a species name

Key Terms

• taxonomy • The science of naming and classifying species

• taxon (taxa)• A grouping of organisms

Linnaean Classification

Fig. 1.7a, p. 10

COMMON NAME

DOMAIN EukaryaKINGDOM Plantae

MagnoliophytaCLASS MagnoliopsidaORDER ApialesFAMILY Apiaceae

DaucusSPECIES carota

carrot

PHYLUM

GENUS

Fig. 1.7b, p. 10

COMMON NAME

DOMAIN Eukarya

PHYLUM MagnoliophytaCLASSORDER Rosales

Magnoliopsida

FAMILY CannabaceaeGENUS Cannabis

SPECIES sativamarijuana

KINGDOM Plantae

Fig. 1.7c, p. 10

COMMON NAME

DOMAIN

PHYLUMCLASSORDERFAMILYGENUS

SPECIES

KINGDOMEukarya

Magnoliophyta

RosalesMagnoliopsida

RosaceaeMalusdomesticusapple

Plantae

Fig. 1.7d, p. 10

COMMON NAME

DOMAIN

PHYLUMCLASS

FAMILYGENUS

SPECIES

KINGDOM

ORDER

EukaryaPlantaeMagnoliophyta

RosalesMagnoliopsida

RosaceaeRosaacicularisarctic rose

Fig. 1.7e, p. 10

COMMON NAME

DOMAIN

PHYLUMCLASS

FAMILYGENUS

SPECIES

KINGDOM

ORDER

dog rosecaninaRosa

EukaryaPlantaeMagnoliophyta

RosalesMagnoliopsida

Rosaceae

3 Domains or 6 Kingdoms

Fig. 1.8a, p. 11

Eukarya

A three-domain system sorts all life into threedomains: Bacteria, Archaea, and Eukarya. TheEukarya domain includes all eukaryotes.

Bacteria Archaea

Fig. 1.8b, p. 11

A six-kingdom classification system in which all eukaryotes have been sorted into one of four kindgoms: protists, plants, fungi, and animals. The protist kingdom includes the most ancient multi-celled and all single-celled eukaryotes.

AnimalsBacteria Archaea Protists Plants Fungi

The Three Domains

A Rose by Any Other Name…

• Individuals of a species share a unique set of traits• Morphological traits• Physiological traits• Behavioral traits

• Species can be hard to distinguish• “biological species concept”

Four Butterflies, Two Species

1.6 The Nature of Science

1) Critical thinking is judging the quality of information before accepting it

2) Scientists make and test potentially falsifiable predictions about how the natural world works

3) Science addresses only what is observable

(1) Thinking About Thinking

• Critical thinking, the self-directed act of judging the quality of information as one learns, is an important part of science

• critical thinking • Judging information before accepting it

• science • Systematic study of the observable world

(2) How Science Works

• Generally, a researcher observes something in nature, uses inductive reasoning to form a hypothesis for it, then uses deductive reasoning to make a prediction about what might occur if the hypothesis is not wrong

Key Terms

• hypothesis • Testable explanation of a natural phenomenon

• inductive reasoning • Drawing a conclusion based on observation

• deductive reasoning • Using a general idea to make a conclusion about a

specific case

(2) How Science Works (cont.)

• Predictions are tested with observations, experiments, or both

• Experiments typically are performed on an experimental group as compared with a control group, and sometimes on models

Key Terms

• prediction • Statement, based on a hypothesis, about a condition that

should exist if the hypothesis is correct

• experiment • A test designed to support or falsify a prediction

• model • Analogous system used for testing hypotheses

Key Terms

• experimental group • In an experiment, the group of individuals who are

exposed to an independent variable

• control group • In an experiment, the group of individuals who are not

exposed to the independent variable that is being tested

(2) How Science Works (cont.)

• Conclusions are drawn from experimental results, or data

• A hypothesis that is not consistent with data is modified

• Making, testing, and evaluating hypotheses is the scientific method

Key Terms

• data • Experimental results

• scientific method • Making, testing, and evaluating hypotheses

The Scientific Method

(2) How Science Works (cont.)

• Biological systems are usually influenced by many interacting variables

• An independent variable influences a dependent variable

Key Terms

• variable • In an experiment, a characteristic or event that differs

among individuals or over time

• independent variable • Variable that is controlled by an experimenter in order to

explore its relationship to a dependent variable

• dependent variable • In an experiment, the variable that is presumably affected

by the independent variable that is being tested

Research in Field and Lab

Key Concepts

• The Nature of Science • Science helps us be objective about our observations by

addressing only the observable• It involves making, testing, and evaluating hypotheses

1.7 Examples of Experiments

• Researchers use experiments to unravel complex natural processes by changing one variable at a time• Experiments are designed in a consistent way • Researchers change an independent variable, then

observe effects of change on a dependent variable • Helps determine cause-and-effect relationship in a

complex natural system

Potato Chips and Stomachaches

• An experiment to determine if the artificial fat Olestra causes stomach cramps

Fig. 1.11, p. 14

A HypothesisOlestra® causes intestinal cramps.

Stepped Art

PredictionBPeople who eat potato chips made with Olestra will be more likely to get intestinal cramps than those who eat potato chips made without Olestra.

ExperimentC

Eats regular potato chips

Control Group

Eats Olestra potato chips

Experimental Group

ConclusionE

Percentages are about equal. People who eat potato chips made with Olestra are just as likely to get intestinal cramps as those who eat potato chips made without Olestra. These results do not support the hypothesis.

ResultsD 93 of 529 people get cramps later (17.6%)

89 of 563 people get cramps later (15.8%)

Potato Chips and StomachachesPotato Chips and Stomachaches

Butterflies and Birds

• How do peacock butterflies defend themselves against predatory birds?

• Observation:

1. Wing-flicking shows wing spots

2. Hissing and clicking sounds

• Predictions:

1. Wing spots scare predators

2. Sounds deter birds

Butterflies and Birds

Fig. 1.12a, p. 15

Fig. 1.12b, p. 15

Fig. 1.12c, p. 15

Results of Butterfly Experiment

1.8 Asking Useful Questions

• Small sample size increases potential for sampling error in experimental results – a subset may be tested that is not representative of the whole

• Researchers design experiments to minimize bias, and use probability rules to check statistical significance of results

• Science is self-correcting because scientists check and test one another’s ideas

Key Terms

• sampling error • Difference between results derived from testing an entire

group of events or individuals, and results derived from testing a subset of the group

• probability • The chance that a particular outcome of an event will

occur; depends on the total number of outcomes possible

• statistically significant • Refers to a result that is statistically unlikely to have

occurred by chance

Sampling Error

• Jelly beans in a jar:• 120 green (30%)• 280 black (70%)

• Sample: • 1 green jelly bean

• Assumption: • all jelly beans are green

Natalie, blindfolded, randomly plucks a jelly bean from a jar. There are 120 green and 280 black jelly beans in that jar, so 30 percent of the jelly beans in the jar are green, and 70 percent are black.

1

Sampling Error

• Sample: 50 jelly beans• 10 green• 40 black

• Assumption: • 20% green • 80% black

• Larger sample is closer to actual ratio

Still blindfolded, Natalie randomly picks out 50 jelly beans from the jar. She ends up picking out 10 green and 40 black ones.

3

Error and Probability

• Error bars indicate sampling error – the range of values above and below average in the sample

Bothering With Bias

• Experimenters risk interpreting results in terms of what they want to find out

• Experiments should be designed to yield data that can be counted or otherwise measured objectively

Key Concepts

• Experiments and Research • Researchers carefully design and carry out experiments in

order to unravel cause-and effect relationships in complex natural systems

1.9 Philosophy of Science

• Science helps us be objective about our observations because it is only concerned with testable ideas about observable aspects of nature

• Opinion and belief have value in human culture, but they are not addressed by science

About the Word “Theory”

• A scientific theory is a longstanding hypothesis that is useful for making predictions about other phenomena – it is our best way of describing reality

• A law of nature describes something that occurs without fail, but for which we do not have a complete scientific explanation

Key Terms

• scientific theory • Hypothesis that has not been disproven after many years

of rigorous testing

• law of nature• Generalization that describes a consistent natural

phenomenon for which there is incomplete scientific explanation

Some Scientific Theories

Limits of Science

• Subjective values (moral, aesthetic or philosophical) can’t be tested by the scientific method

• Science doesn’t address the supernatural, or anything beyond nature

The Secret Life of Earth (revisited)

• We have discovered only a small fraction of the species that share Earth with us

• Mouse lemur discovered in 2005