Chapter 1Introduction: Themes in the Study of

Life

Biology: Scientific study of life

Bio- = life

The phenomenon we call life defies a simple, one-sentence definition

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Properties of Life

(c) Response to the environment

(a) Order

(d) Regulation

(g) Reproduction (f) Growth and development

(b) Evolutionary adaptation

(e) Energy processing

Themes of Biology

Identifiable common themes Makes study of complex

subject more manageable

Pay attention as we move through semester

We will see evidence of themes many times

Theme: Hierarchy of Life

Biological systems are much more than the sum of their parts

Emergent properties

New properties emerge with each step upward in the hierarchy of biological order

Reductionism

Involves reducing complex systems to simpler components that are more manageable to study

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Hierarchy of Life

From atoms to organisms

Cell

4.) Cells

6 6.) Organs and organ systems

7 5.) Tissues

3.) Organelles

50 µm

10 µm

1 µm

1.) Atoms

2.) Molecules

Theme: Organisms Interact with Other Organisms and their

Environment Organisms exist in constant

interaction with other living organisms and the physical world

Nutrients and other vital materials are cycled through living organisms, into the environment and back again

Global climate change is just one of many examples of this interaction

Theme: Energy Transfer and Transformation

Activities of life

Require organisms to perform work, which depends on an energy source

The exchange of energy between an organism and its surroundings

Often involves the transformation of one form of energy to another

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Energy Conversion

Energy flows through an ecosystem Usually entering as sunlight and exiting as

heat

Producers(plants and other

photosynthetic

organisms)

Consumers

(including animals)

Sunlight

Chemical

energy

Heat

Heat

Ecosystem

Theme: Structure and Function

Things are constructed based on their function

Ex. Wheels are round so they can roll so they can move a vehicle

Can you think of some biological examples of structure and function?

Theme: The Cell The cell is the lowest level of organization

that can perform all activities required for life

All living organisms are made of cells

Types of Cells All cells share certain characteristics

They are all enclosed by a membrane

They all use DNA as genetic information

There are two main forms of cells

Prokaryotic: No membrane bound nucleus

Eukaryotic: Does have membrane bound nucleus

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Prokaryotic cells vs. Eukaryotic cells

EUKARYOTIC CELL

Membrane

Cytoplasm

Organelles

Nucleus (contains DNA) 1 µm

PROKARYOTIC CELL

DNA

(no nucleus)

Membrane

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Theme: The Cell’s Heritable Information

Cells contain chromosomes made partly of DNA, the substance of genes

Which program the cell’s production of proteins and transmit information from parents to offspring

Egg cell

Sperm cell

NucleicontainingDNA

Fertilized eggwith DNA fromboth parents

Embyro’s cells with copies of inherited DNA Offspring with traits

inherited fromboth parents

Theme: Evolution Main theme of biology

Evolution explains diversity and unity of all living organisms on our planet

Organization: Three Domains of Life

At the highest level, life is classified into three domains

Bacteria

Archaea

Eukarya

Organization: Three Domains of Life

Domain Bacteria and Domain Archaea

Consist of prokaryotes

Domain Eukarya, the eukaryotes, includes

Multiple kingdoms: Protista

Kingdom Plantae

Kingdom Animalia

Kingdom Fungi