Chapter 1Chapter 1

Exploring LifeExploring Life

1. Define biology1. Define biology

2. Define living2. Define living

3. Scientific Inquiry3. Scientific Inquiry

4. Biological Hierarchy4. Biological Hierarchy

5. Biological Themes5. Biological Themes

What is Biology?What is Biology?

Definition Definition

Scientific study of LIFEScientific study of LIFE

What is Living?What is Living?

To be classified as living, these To be classified as living, these criteria must be met:criteria must be met:

1.1. Highly ordered structureHighly ordered structure

2.2. Evolutionary adaptationEvolutionary adaptation

3.3. Respond to environmentRespond to environment

What is living?What is living?

4. Regulation of internal functions4. Regulation of internal functions

* Homeostasis* Homeostasis

5. Process energy5. Process energy

6. Grow & Development6. Grow & Development

7. Reproduce7. Reproduce

* Hereditary Material* Hereditary Material

Is a virus living?Is a virus living?

Why or Why not?Why or Why not?

How is Biology How is Biology Studied?Studied?

Science (“to know”)Science (“to know”)

IncludesIncludes

1. Body of knowledge1. Body of knowledge

2. Scientific Inquiry process2. Scientific Inquiry processSearch for information & explanationSearch for information & explanation

focus on specific questionsfocus on specific questions

Scientific InquiryScientific Inquiry

Two types Two types 1.1. Discovery scienceDiscovery science

Describe natural processesDescribe natural processes

ObservationObservation

Inductive Reasoning (generalizations Inductive Reasoning (generalizations from specific observations)from specific observations)

““All organisms are made of cells”All organisms are made of cells”

Scientific InquiryScientific Inquiry

2. Hypothesis-based science2. Hypothesis-based scienceFocus on explanationsFocus on explanations*Hypothesis*HypothesisDeductive ReasoningDeductive Reasoninggeneral to specificgeneral to specificif ---> thenif ---> then

““if all organisms are made of cells, if all organisms are made of cells, then humans are composed of cells”then humans are composed of cells”

Observations

Questions

Hypothesis # 1:Dead batteries

Hypothesis # 2:Burnt-out bulb

Prediction:Replacing batterieswill fix problem

Prediction:Replacing bulbwill fix problem

Test prediction

Test does not falsify hypothesis

Test prediction

Test falsifies hypothesisFigure 1.25

Hypothesis-Based Hypothesis-Based ScienceScience

Idealized Scientific MethodIdealized Scientific Method

1. Observation1. Observation

2. Question2. Question

3. Hypothesis3. Hypothesis

4. Experiment4. Experiment

5. Conclusion5. Conclusion

Scientific MethodScientific Method

1.1. Must be testableMust be testable

2.2. Must be falsifiableMust be falsifiable

3.3. Experiments must be repeatableExperiments must be repeatable

4.4. Control effects of unwanted Control effects of unwanted variablesvariables

5.5. Supernatural phenomena is not Supernatural phenomena is not addressedaddressed

DataData

Two types of recorded observationsTwo types of recorded observations

1. Quantitative1. Quantitative

2. Qualitative2. Qualitative

Figure 1.24

Hierarchy of BiologyHierarchy of Biology

Levels of OrganizationLevels of Organization

1. Molecules1. Molecules

2. Organelles2. Organelles

subcellular, specific functionssubcellular, specific functions

3. Cells3. Cells

Hierarchy of BiologyHierarchy of Biology

4. Tissues4. Tissues

5. Organs5. Organs

6. Organ System6. Organ System

Hierarchy of BiologyHierarchy of Biology

7.7. OrganismOrganism

8.8. PopulationPopulation

9.9. CommunityCommunity

Hierarchy of BiologyHierarchy of Biology

10. Ecosystem10. Ecosystem 11. Biosphere11. Biosphere

From the biosphere to organismsFrom the biosphere to organisms

Figure 1.3

1 The biosphere

Cell

8 Cells

6 Organs and organ systems

7 Tissues

10 Molecules

9 Organelles

50 µm

10 µm

1 µm

Atoms

Figure 1.3

Themes Themes of of BiologyBiology

Table 1.1

Themes of BiologyThemes of Biology

1.1. CellCellBasic unit of lifeBasic unit of life

smallest unit that can perform all smallest unit that can perform all activities of lifeactivities of life

25 µmFigure 1.5

Two Cell TypesTwo Cell Types

1. Prokaryotic1. Prokaryoticno membrane bound nucleusno membrane bound nucleus

no membrane bound organellesno membrane bound organelles

primarily bacteriaprimarily bacteria

Two cell typesTwo cell types

2. Eukaryotic2. Eukaryoticmembrane bound nucleusmembrane bound nucleus

several membrane bound organellesseveral membrane bound organelles

ex. Protists, fungi, plants, animalsex. Protists, fungi, plants, animals

EUKARYOTIC CELL

Membrane

Cytoplasm

Organelles

Nucleus (contains DNA)1 µm

PROKARYOTIC CELL

DNA

(no nucleus)

Membrane

Figure 1.8

Themes of BiologyThemes of Biology

2.2. DNA is heritable informationDNA is heritable informationallows for continuity of allows for continuity of

life by transmitting life by transmitting

biological informationbiological information

DNA

Cell

Nucleotide

ACTA

T

A

CC

G

G

TA

TA

(b) Single strand of DNA. These geometric shapes and letters are simple symbols for the nucleotides in a small section of one chain of a DNA molecule. Genetic information is encoded in specific sequences

of the four types of nucleotides (their names are abbreviated here as A, T, C, and G).

(a) DNA double helix. This model shows

each atom in a segment of DNA.Made up of two long chains of building blocks called nucleotides, a DNA molecule takes the three-dimensional form of a double helix.

Nucleus

Themes of BiologyThemes of Biology

3.3. Emergent propertiesEmergent properties

refers to unique, new property of each refers to unique, new property of each hierarchy level not present at the simpler hierarchy level not present at the simpler

levellevel

Themes of BiologyThemes of Biology

4.4. Feedback RegulationFeedback Regulationkind of supply and demand economykind of supply and demand economy

regulate production of enzymes, proteinsregulate production of enzymes, proteins

Two types:Two types:1. Negative feedback (product turns it off)1. Negative feedback (product turns it off)

2. Positive feedback (product speeds it up)2. Positive feedback (product speeds it up)

Negative FeedbackNegative Feedback

B

A

C

D

Enzyme 1

Enzyme 1

Enzyme 2

Enzyme 3

DD D D

D

D

DD

DD

C

B

A Negative feedback

Figure 1.11

Positive FeedbackPositive Feedback

WW

X

Y

Z

ZZ

ZZ

Z

Z Z Z

Z Z Z Z

Z

ZZ Z

ZZ

Y

X

Enzyme 4

Enzyme 5

Enzyme 6

Enzyme 4

Enzyme 5

Enzyme 6

Positivefeedback

Figure 1.12

Themes of BiologyThemes of Biology

5.5. Interaction with environmentInteraction with environmentinteractionsinteractions

abiotic factorsabiotic factors

biotic factorsbiotic factors

6.6. Energy and lifeEnergy and lifeOrganisms must perform workOrganisms must perform work

Energy flowEnergy flow

Themes of BiologyThemes of Biology

7.7. Unity in the Unity in the

Diversity Diversity

of Lifeof Life Cilia of Paramecium.The cilia of Parameciumpropel the cell throughpond water.

Cross section of cilium, as viewedwith an electron microscope

15 µm

1.0 µm

5 µm

Cilia of windpipe cells. The cells that line the human windpipe are equipped with cilia that help keep the lungs clean by moving a film of debris-trapping mucus upward.Figure 1.16

Paradox of Unity & Paradox of Unity & DiversityDiversity

UnityUnity

1. DNA is the genetic, heritable 1. DNA is the genetic, heritable material, universal genetic material, universal genetic

codecode

2. Universal processes2. Universal processes

Replication, Transcription, Replication, Transcription, TranslationTranslation

Paradox of Unity & Paradox of Unity & DiversityDiversity

DiversityDiversity

vast collection of living organisms vast collection of living organisms on Earthon Earth

categorized into levels based on similaritiescategorized into levels based on similarities

Classifying LifeClassifying Life

Taxonomy – branch of bio that names Taxonomy – branch of bio that names and classifies speciesand classifies species DomainDomainKingdomKingdomPhylumPhylumClassClassOrderOrderFamilyFamilyGenusGenusSpeciesSpecies

Classifying LifeClassifying Life

3 Domains3 Domains1.1. Bacteria - prokaryotesBacteria - prokaryotes

2.2. Archaea - prokaryotesArchaea - prokaryotes

3.3. Eukarya - eukaryotesEukarya - eukaryotes

Figure 1.15

100 µm

0.5 µm

4 µmBacteria are the most diverse and widespread prokaryotes and are now divided among multiple kingdoms. Each of the rod-shapedstructures in this photo is a bacterial cell.

Protists (multiple kingdoms)are unicellular eukaryotes and their relatively simple multicellular relatives.Pictured here is an assortment of protists inhabiting pond water. Scientists are currently debating how to split the protistsinto several kingdoms that better represent evolution and diversity.

Kingdom Plantae consists of multicellula eukaryotes that carry out photosynthesis, the conversion of light energy to food.

Many of the prokaryotes known as archaea live in Earth‘s extreme environments, such as salty lakes and boiling hot springs. Domain Archaea includes multiple kingdoms. The photoshows a colony composed of many cells.

Kindom Fungi is defined in part by thenutritional mode of its members, suchas this mushroom, which absorb nutrientsafter decomposing organic material.

Kindom Animalia consists of multicellular eukaryotes thatingest other organisms.

DOMAIN ARCHAEA

Themes of BiologyThemes of Biology

8.8. Evolution Evolution

accounts for diversity based on life’s accounts for diversity based on life’s unityunity

CharlesCharles

DarwinDarwin

Figure 1.18

EvolutionEvolution

Charles Darwin in Charles Darwin in The Origin of The Origin of Species Species articulated two main articulated two main points:points:

1. Descent with modification1. Descent with modification

2. Natural selection2. Natural selection

Themes of BiologyThemes of Biology

9.9. Structure & Function – Structure & Function – everything everything has purpose at all biological levelshas purpose at all biological levels

10.10. Scientific InquiryScientific Inquiry

11.11. Science, Technology, & Society – Science, Technology, & Society – applications of science & production of applications of science & production of technologies to benefit societytechnologies to benefit society