CHAPTER 1 INTRODUCTION: TEN THEMES IN THE STUDY OF LIFE

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Biology, the study of life, is rooted in the human spirit. Biology has been pursued for centuries by men of God as they

attempted to learn about God as they studied nature—called:

Natural Theology

Introduction

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Who were these “natural theologians?”

Blaise Pascal (1623-1662)

Jansenist, a group of Calvinist French Catholic who emphasized salvation through God’s love and grace

Roger Bacon (1214-1294)

English Monk used glass to magnify organisms

Louis Pasteur

Experiments that demonstrated the cell theory—“all living things are made of cells and all cells come form pre-existing cells”

Lord Kelvin

Opponent of Darwin Father of “Energetics”

Carolus Linnaeus 1701-1778

Father of Modern taxonomy Accepted the Biblical account of

creations Concluded that created kinds never

alter enough to form new and different kinds

The list goes on:

Michael FarradayJohann KeplerIsaac NewtonGregor MendelLeonardo da VinciJoseph Lister

Biologists explore life form a global to a microscopic scale

Life’s basic characteristic is a high degree of order.

Each level of biological organization has emergent properties

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 1.2(1) Fig. 1.2(2)

Biological organization is based on a hierarchy of structural levels, each building on the levels below. At the lowest level are atoms that are

ordered into complex biological molecules.

Many molecules are arranged into minute structures called organelles, which are the components of cells.

Cells are the subunits of organisms, the units of life.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 1.2(3)

Some organisms consist of a single cell, others are multicellular aggregates of specialized cells.

What is the upward hierarchy of biological complexity?

Cells Tissues Organs Organ systems Organisms Populations Communities Ecosystems Biomes

Novel properties emerge at each step upward in the biological hierarchy.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

These emergent properties result from interactions between components.A cell is certainly much more than a bag of molecules.

This theme of emergent properties accents the importance of structural arrangement.

The emergent properties of life are not supernatural, but simply reflect a hierarchy of structural organization.

Life resists a simple, one-sentence definition, yet we can recognize life by what living things do.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 1.3

Whether multicellular or unicellular, all organisms must accomplish the same functions:

Growth and development

Metabolism

Regulation

Respond to environment

Figure 1.3bx Reproduction

Reproduction

Living things exhibit order

Figure 1.3 Some properties of life

Figure 1.3ax Order

The complex organization of life presents a dilemma to scientists seeking to understand biological processes.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

We cannot fully explain a higher level of organization by breaking down to its parts.

At the same time, it is futile to try to analyze something as complex as an organism or cell without taking it apart.

Reductionism, reducing complex systems to simpler components, is a powerful strategy in biology.

Reductionism is balanced by the longer-range objective of understanding emergent properties.

Science is a process

Science seeks natural causes for natural phenomena.

The scope of science is limited to the study of structures and processes that we can observe and measure, either directly or indirectly.

Verifiable observations and measurements are the data of discovery science.

In some cases the observations entail a planned detailed dissection and description of a biological phenomenon, like the human genome.

In other cases, curious and observant people make totally serendipitous discoveries.

In 1928, Alexander Fleming accidentally discovered the antibacterial properties of Pencillium when this fungus contaminated some of his bacterial cultures.

Discovery science can lead to important conclusions via inductive reasoning. An inductive conclusion is a generalizationthat summarizes many concurrent observations.

Organizing Species

Linnaeus developed our system of organizing using 7 taxons

KingdomPhylum Class Order Family Genus species

The scientific name is made of the Genus and species name (hence binomial nomenclature)

Examples:Homo sapiensDrosophila melanogasterSalmonella typhimurium

Linnaeus used 2 groups

Plant Kingdom Animal Kingdom

Whitaker used 5 kingdoms

Monerans Plants Animals Fungi Protists

Scientists have now added a new taxon, called a “domain”

Current system uses 3 domains:Bacteria Archaea Eukarya

Both are prokaryotic

Monerans are Prokaryotic

Smaller than eukaryotes No membrane bound organelles DNA is not contained in a nucleus

Plants, animals, fungi and protists are eukaryotes

Larger Have membrane bound nucleus

containing DNA Have membrane bound organelles

that compartmentalize cells

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