Post on 03-Jan-2016
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Human BiologySylvia S. Mader
Michael Windelspecht
Chapter 1 Exploring Life and Science
Lecture Outline
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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?
What characteristics are shared by living organisms?
• Organized from the atom to the biosphere• Use materials and energy from the environment• Reproduce offspring• Growth and development• Maintain a relatively constant internal
environment (homeostasis)• Respond to internal and external stimuli• Evolutionary history through which organisms
change over time
1.1 The characteristics of life
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
How do we classify humans?
Human House catDomain Eukarya EukaryaKingdom Animalia AnimaliaPhylum Chordata ChordataClass Mammalia MammaliaOrder Primates CarnivoraFamily Hominidae FelidaeGenus Homo FelisSpecies sapiens domesticus
1.2 Humans are related to other animals
What distinguishes humans?
• Cultural heritage or patterns of our behavior passed from one generation to the next
• Highly developed brains• Completely upright stance• Creative language skills• Varied tool use• Modification of our environment for our own
purpose which may threaten the biosphere
1.2 Humans are related to other animals
What do we know about science?• Science is a way of knowing about the natural
world
• Science and scientists should be objective
• Scientific conclusions may change or be modified as our understanding and technology increase
• Science is studied using the scientific method
1.3 Science is a process
Scientific Theories in Biology
1.3 Science is a process
The steps of the scientific method1.3 Science is 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
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Observations: many patients had a particular bacterium near their ulcers
• Hypothesis: Helicobacter pylori is the cause of gastritis and ulcers.
• Experiment/observations:
1st – H. pylori was isolated and grown from ulcer patients
2nd – humans swallowing a H. pylori solution resulted in 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 is a process
A controlled study• Variables:
• Experimental variable is the variable 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 is a process
1.3 Science is a process
A controlled study in actionCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a.
b.
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.
Testgroup 2:receivedantibiotic B
Controlgroup:receivedplacebo
Testgroup 1:receivedantibiotic A
Conclusion:Hypothesis is
supported:Antibiotic B is
a bettertreatment forulcers thanantibiotic A.
ControlGroup
TestGroup 1
TestGroup 2E
ffec
tive
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reat
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(a-b): © blickwinkel/Alamy; (c): © Phanie/ Photo Researchers, Inc.
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Reading about scientific information
• Scientific journals are considered the best source of information but can be difficult for the lay person to understand
• Often the lay person reads secondary sources and must be wary of information taken out of context
• Be careful of information on the Internet by using reliable sources such as URLs with .edu, .gov and .org
1.3 Science is a process
What should you look for when you read about science?
• Beware of anecdotal data
• 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
Reading a GraphWhat information does this line graph convey?
1.4 Making sense of a scientific study
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
standard error
130
120
100Site 1 Site 2 Site 3 Site 4
X-axis
Y-axis
Dia
met
er o
f T
rees
(cm
)
110Data
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
• 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
Everyone is Responsible
• The Western world believes that science and technology improves our lives.
• All citizens should assume responsibility.
• 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 venture through this text. Consider your opinions.
1.5 Science and social responsibility