1 chapter 01: copyright © the mcgraw-hill companies, inc. permission required for reproduction or...
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Chapter 01:
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Exploring Life and Science
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Points to ponder
• What is biology?• What characterizes life?• How do we classify life?• Where do humans fit into the big picture?• How do we study science?• Where is scientific information published and
what should you be aware of?
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What characteristics are shared by living organisms?
• Organized• Use materials and energy from the environment• Maintain a relatively constant internal
environment (homeostasis)• Respond to internal and external stimuli• Reproduce and grow• Have an evolutionary history through which
organisms change over time
1.1 The Characteristics of Life
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Natural Selection
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How are living things organized?1.1 The Characteristics of Life
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
nervous system shoot system
leaf
photosynthetic tissue
plant cell
brain
nervous tissue
neuron
BiosphereRegions of the Earth’s crust,
waters, and atmosphere inhabitedby living things
EcosystemA community plus the physical environment
CommunityInteracting populations in a particular area
PopulationOrganisms of the same species
in a particular area
OrganismAn individual; complex individuals
contain organ systems
Organ SystemComposed of several organs
working together
OrganComposed of tissues functioning
together for a specific task
TissueA group of cells with a common
structure and function
CellThe structural and functional
unit of all living things
MoleculeUnion of two or more atoms
of the same or different elements
AtomSmallest unit of an element composed of
electrons, protons, and neutrons
Figure 1.2 Levels of biological organization.
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Diversity of Living Things
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How Do We Classify Organisms?
• Taxonomy:• According to their characteristics• Three Domain Classification system (trunk)
• Five (or Six)-kingdom classification system (branches)
• Possible characteristics– Presence or absence of a nucleus– Number of cells– Type of metabolism
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Domains and Kingdoms
01.02.03.04.0 0.51.52.53.5
common
ancestor
(first cells)
EUKARYA
common ancestor
BACTERIA
ARCHAEA
Protists
Plants
Fungi
Animals
Billions of Years Ago (BYA)
domains
kingdoms
3 Domains
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Domain Eukarya; Kingdom Protista
Paramecium, a unicellular protozoan
• Algae, protozoans,
slime molds, and
water molds
• Complex single cell
(sometimes filament
colonies, or even
multicellular
• Absorb, photosynthesize,
or ingest food
1 µm
Domain Eukarya; Kingdom Fungi
• Molds, mushrooms, yeasts,
and ringworms
• Mostly multicellular filaments with
specialized, complex cells
• Absorb food
Cantharellula, a club fungi
Domain Eukarya; Kingdom Plantae
Passiflora, passion flower, a flowering plant
• Certain algae, mosses, ferns,
conifers, and flowering plants
• Multicellular, usually with
specialized tissues,
containing complex cells
• Photosynthesize food E.coli, a bacterium
Domain Bacteria
• Prokaryotic cells
of various shapes
• Adaptations to
all environments
• Absorb, photosynthesize,
or chemosynthesize food
• Unique chemical
characteristics
Methanosarcina mazei, an archaeon
• Prokaryotic cells
of various shapes
• Adaptations to
extreme environments
• Absorb or
Chemosynthesize food
• Unique chemical
characteristics
Domain Archaea
Vulpes, a red fox
• Sponges, worms, insects,
fishes, frogs, turtles,
birds, and mammals
• Multi cellular with
specialized tissues
containing complex cells
• Ingest food
Domain Eukarya; Kingdom Animalia
(protist):© Michael Abby/Visuals Unlimited; (fungi): © Ingram Publishing RF; (animal): © Corbis ; (plant): © Pat Pendarvis; (Archaea): © Ralph Robinson/Visuals Unlimited; (Bacteria): © A.B. Dowsett/SPL/Photo Researchers, Inc.
1.6 µm
1.5 µm
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_________________________
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How do we classify humans?Human House cat
Domain Eukarya EukaryaKingdom Animalia AnimaliaPhylum Chordata ChordataClass Mammalia MammaliaOrder Primates CarnivoraFamily Hominidae FelidaeGenus Homo FelisSpecies sapiens domesticus
1.2 Humans Are Related to Other Animals
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What distinguishes humans?
• Brains• Bipedal• Language• Tool use• We modify our environment
1.2 Humans Are Related to Other Animals
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What do we know about science?• Science is a way of knowing about the natural
world.
• Science and scientists should be objective.objective =subjective =
• Scientific conclusions aren’t “set in stone”
• Science is studied using the scientific method.
1.3 Science as a Process
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Scientific theories in biology1.3 Science as a Process
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The Scientific Method1.3 Science as a Process
The results are analyzed,and the hypothesis issupported or rejected.
Many experiments andobservations support a
theory.
The hypothesis istested by experiment
or further observations.
Input from various sourcesis used to formulate a
testable statement.
New observationsare made, and previous
data are studied.
Hypothesis
Observation
Experiment/Observations
Conclusion
Scientific Theory
Figure 1.8 The scientific method.
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• Observations: Many patients had a particular bacterium near their ulcers.
• Hypothesis: Helicobacter pylori is the cause of gastritis and ulcers.
How the cause of ulcers was discovered:
The scientific method in action!
1.3 Science as a Process
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• Experiment/observations:
1st – H. pylori was isolated and grown from ulcer patients.
2nd – Humans swallowing a H. pylori solution developed inflammation in their stomachs.
• Conclusion: H. pylori was the cause of most ulcers and can be cured by antibiotics.
How the cause of ulcers was discovered:
The scientific method in action
1.3 Science as a Process
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A controlled study• Variables
• Experimental variable is the factor that is purposely changed or manipulated.
• All other variables need to remain constant.
• Groups• Test group is a group of subjects that are
exposed to the experimental variable.• Control group is a group for comparison that is
not exposed to the experimental variable.
1.3 Science as a Process
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1.3 Science as a Process
A controlled study in action
Figure 1.10 Design of a scientific study.
a.
c.
d.
Subjects weredivided intothree groups.
Perform Experiment:Groups were treated the same
except as noted.
Large numberof subjectswere selected.
State Hypothesis:Antibiotic B is a better treatment for
ulcers than antibiotic A.
Collect Data:Each subject was examinedfor the presence of ulcers.
Test group 2:received
antibiotic B
Control group:receivedplacebo
Test group 1:received
antibiotic A
a (both): © blickwinkel/Alamy; c: © Phanie/Photo Researchers
ControlGroup
TestGroup 1
TestGroup 2
60
10
80
Eff
ecti
ven
ess
of
Tre
atm
ent
(%)
80
60
40
20
0
100
Conclusion:Hypothesis is
supported:Antibiotic B is
a bettertreatment forulcers thanantibiotic A.
Treatment of Ulcers by Antibiotics
b.
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Reading about scientific information
• Scientific journals are considered the best source of information but can be difficult for the average person to understand.
• Often we read secondary sources and must be wary of information taken out of context.
• Be careful of information on the Internet! Use reliable sources such as URLs
with .edu, .gov and .org.
1.3 Science as a Process
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What should you look for when you read about science?
• Beware of anecdotal data (stories).• Understand methodology and results.• Does the data justify the conclusions inferred by
the scientists?• Be able to read a graph.• Have some understanding of statistics.
1.4 Making Sense of a Scientific Study
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Reading a graphWhat information does this line graph convey?
1.4 Making Sense of a Scientific Study
Figure 1.11 The presentation of scientific data.
standard error
225
200
150Week 1 Week 2 Week 3 Week 4
x-axis
y-axis
Blo
od
Ch
ole
tste
rol (
mg
/dL
)
175Data
Variation in Blood Cholesterol Levels
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Does science have social responsibilities?
• Science is a way of acquiring knowledge about the natural world through a systematic process separating it from ethics, religion, and aesthetics.
1.5 Science and Social Responsibility
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Does science have social responsibilities?
• Technology is the application of scientific knowledge to human interests.- Biotechnology (genetically modified bacteria and
genetically modified crops)
- Gene technology (cloning of humans or gene therapy to modify inheritance)
- Use of stem cells from embryos (embryonic stem cells)
1.5 Science and Social Responsibility
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Everyone is responsible! • The Western world believes that science and
technology improve our lives.• All citizens should assume responsibility. You
make the future happen!• Everyone needs to be involved in making value
judgments about the proper use of technology. • You will learn more about all of these as you
prgress through this course. Consider your opinions.
1.5 Science and Social Responsibility