Introduction: Themes in theStudy of Life

Chapter 1

Biology

• The scientific study of life– Scientists use the Scientific Method to answer

questions posed by the living world

• Much of biology focuses on how organisms have adapted to life in myriad environs on our planet– Evolution is the central theme of biology– Mother-of-Pearl Plant (Graptopetalum paraguayense)

is adapted to life with limited water

Properties of Life

1. Order2. Regulation

– Homeostasis (balance within limits)

3. Energy Processing4. Evolutionary Adaptation5. Response to Environment6. Reproduction

– Inheritance of genetic material (DNA)

7. Growth and Development– Regulated by DNA

Check Your Understanding

• What is the scientific method and what is its role in biology?

• Why is evolution considered to be the unifying, central theme of biology?

• Discuss the seven major properties associated with all living things?

THEMES OF BIOLOGY

New Properties Emerge at Each Level in the Biological Hierarchy

• Levels of Organization– See figure on the left

• Emergent Properties– New functions that develop

as complexity increases– Not present in level below

• Reductionism studies complex systems by looking at smaller, more manageable parts

• Systems Biology models the interactions within system based on knowledge of individual parts

Organisms Interact with Other Organisms and Their Environment

Life Requires Energy Transfer and Transformation

• Photosynthesis– Light (Kinetic Energy) and

CO2 to organic molecules (Chemical Energy)

– Producers

• Respiration– Organic molecules to CO2

and new chemical energy– Consumers

Structure and Function are Correlated at All Levels of Biological Organization

Form Fits Function (and vice versa)

The Cell is the Basic Structural and Functional Unit of Life

PROKARYOTE EUKARYOTE

BacteriaLack internal membranes

Protozoa, Fungi, Plants, AnimalsPossess internal membranes

The Continuity of Life is Based on the Heritable Information Found in DNA

• Replication– DNA creates new DNA– Genome is term for all the

genetic material in a single cell

• Protein Synthesis– Transcription

• DNA creates RNA

– Translation• RNA creates proteins

Feedback Mechanisms Regulate Biological Systems

NEGATIVE FEEDBACK POSITIVE FEEDBACK

Check Your Understanding• Describe how each level within the hierarchy of life is related to the level

below it and the level above it. Define emergent properties of life and how this relates to the hierarchy. Differentiate between reductionism and systems biology.

• Differentiate between photosynthesis and cellular respiration. Between producers and consumers. How do these terms relate to the energy transformations of life?

• Describe the relationship between form and function using a bird’s wing bones as an example.

• Differentiate between a prokaryotic and a eukaryotic cell.• Differentiate between DNA replication, DNA transcription, and RNA

translation.• Differentiate between positive and negative feedback mechanisms.

Provide one example of each type of mechanism.

EVOLUTIONThe Core Theme of Biology

Classifying the Diversity of Life

• Taxonomy is the science of classifying organisms– Domains are the most

encompassing levels– Species is the most specific

designation

• Binomial System of Nomeclature– Genus species

Three Domains of Life

• Bacteria (prokaryotes)• Archaea (prokaryotes)• Eukarya (eukaryotes)– Plantae– Fungi– Animalia– Protista

Unity in the Diversity of Life

Charles Darwin and the Theory of Natural Selection

• On the Origin of Species by Means of Natural Selection (1859)1. Contemporary species arose from a succession of

ancestors• “Decent with modification”

2. Decent with modification is caused by “natural selection”• Individuals vary within a population based on heritable traits• Populations produce far more offspring than can possibly

survive which leads to competition• Species are suited (adapted) to their environment provided

the environment does not change

The Tree of Life

Check Your Understanding

• Differentiate between a domain and a species. How are species universally identified when their names are written or typed?

• Differentiate between the organisms belonging to the domains Bacteria, Archaea, and Eukarya.

• How does a cilia in a paramecium and on cell lining the respiratory tract of a human illustrate the process of evolution?

• What work by Charles Darwin changed the face of biology forever? What three things did Darwin say were necessary for decent with modification to occur?