Transcript Chapter 1

Chapter 01
Lecture Outline
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monarch butterfly
feeding on nectar
Masai giraffes
giant sequoia
planet Earth
Figure 1.1
mushroom on northern
forest floor
humans in a city
male peacock
displaying feathers
(sequoia): © Robert Glusic/Getty RF; (mushroom): © IT Stock/Age Fotostock RF; (peacock): © Brand X Pictures/PunchStock RF; (humans): © Heath
Korvola/UpperCut Images/Getty RF; (giraffes): © Dr. Sylvia S. Mader; (butterfly): © Creatas/PunchStock RF; (Earth): © Ingram Publishing/Alamy RF
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1.1 The Characteristics of Life
• Life exists almost everywhere on Earth.
• Earth possesses a great variety of diverse
life forms.
• All living things have certain characteristics
in common.
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The Characteristics of Living
Organisms
•
•
•
•
•
•
•
Are organized
Acquire materials and energy
Reproduce
Respond to stimuli
Are homeostatic
Grow and develop
Have the capacity to adapt
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Organisms organized
in a hierarchy of levels
Organisms
human
tree
• A cell is the smallest unit
of life.
• A tissue is a group of
similar cells that perform
a particular function.
• Several tissues join
together to form an
organ.
• Organs work together to
form an organ system.
Organ Systems
organ system
Organs
leaf
brain
Tissues
leaf tissues
nerve tissue
plant cell
nerve cell
Cells
DNA molecule
Molecules
Atoms
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• Organisms need external material and
energy sources to maintain their
organization and carry on life’s activities.
• Energy is the capacity to do work.
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Organisms Reproduce
• Life arises from life.
• Genes are units of information within an
individual’s DNA.
• Reproduction is the process by which an
organism makes more of itself.
• DNA which directs cellular functions is
duplicated prior to an organism
reproducing.
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Organisms Respond to Stimuli
• Organisms respond to external stimuli by
moving toward or away from the stimuli.
• Organisms use a variety of mechanisms
for movement in response to stimuli.
• Movement of an organism constitutes a
large part of its behavior.
• Behavior is directed toward avoiding
injury, acquiring food or mating.
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Organisms are Homeostatic
• Homeostasis (“staying the same”) refers
to the requirement that organisms maintain
a relatively constant internal environment.
• For example, human body temperature
fluctuates slightly throughout the day.
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Figure 1.4
• Growth – increase in size or number of cells
• Development – changes that take place
from conception to death
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Organisms Have the Capacity
to Adapt
• During the nearly 4 billion years that life
has been on Earth, the environment has
constantly changed.
• Some individuals of a species may be
better fit in a new environment.
• Adaptations are features that make
individual organisms better suited to the
new environment.
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Organisms Have the Capacity
to Adapt
• Individuals better adapted to their
environment tend to produce more offspring.
• Natural Selection is the differential
reproductive success of adapted individual.
– Results in changes of characteristics of a
population over time
• Evolution the change in frequency of traits
in populations and species.
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1.2 The Classification of
Organisms
• Living organisms are assigned to groups
based upon their similarities.
• Systematics is the discipline of identifying
and classifying organisms.
• Each organism is classified in a domain,
kingdom, phylum, class, order, family,
genus and species.
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Domains
• Domains are the largest classification
category.
• Organisms are assigned to 1 of 3 domains
based on biochemical and genetic evidence:
domain Archea, domain Bacteria, or domain
Eukarya.
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Domains
• Domains Archea and Bacteria include
unicellular prokaryotic cells.
– Cells that lack a true nucleus
• Domain Eukarya include eukaryotic cells.
– Cells with a true nucleus
– Genes found in the DNA within the nucleus
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Domain Archaea
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• Archaea live in
extreme
environments.
– Too little O2, too salty,
too hot, or too acidic
for most other
organisms
DOMAIN ARCHAEA
Methanosarcina mazei
a. Archaea are capable of living in extreme environments.
1.6 µm
© Ralph Robinson/Visuals Unlimited
Figure 1.5a
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Domain Bacteria
• Bacteria are found
almost everywhere on
the planet Earth.
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DOMAIN BACTERIA
• Some are present
within humans.
• Some bacteria cause
disease but many are
beneficial.
Escherichia coli
b. Bacteria are found nearly everywhere.
1.5 µm
© A.B. Dowsett/SPL/Photo Researchers, Inc.
Figure 1.5b
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Kingdoms
• Eukaryotes (Domain Eukarya) are further
categorized into one of four Kingdoms
– Kingdom Protista – may be several kingdoms
– Kingdom Fungi
– Kingdom Plantae
– Kingdom Animalia
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DOMAIN EUKARYA
Kingdom
Protista
Organization
Type of Nutrition
Complex single cell,
some multicellular
Absorb,
photosynthesize,
or ingest food
Representative Organisms
Protozoans,
algae, water molds,
and slime molds
paramecium
Fungi
Some unicellular,
most multicellular
filamentous forms
with specialized
complex cells
euglenoid
Multicellular form
with specialized
complex cells
Molds, yeasts,
and mushrooms
Multicellular form
with specialized
complex cells
yeast
mushroom
bracket fungus
Photosynthesize
food
moss
Animalia
dinoflagellate
Absorb food
black bread mold
Plantae
slime mold
fern
pine tree
nonwoody
flowering plant
Mosses, ferns,
nonwoody and
woody flowering
plants
Invertebrates,
fishes, reptiles,
amphibians, birds,
and mammals
Ingest food
sea star
earthworm
finch
raccoon
c. Eukaryotes are divided into four kingdoms.
Figure 1.5c
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DOMAIN ARCHAEA
DOMAIN BACTERIA
Methanosarcina mazei
a. Archaea are capable of living in extreme environments.
Escherichia coli
b. Bacteria are found nearly everywhere.
1.6 m
1.5 m
DOMAIN EUKARYA
Kingdom
Protista
Organization
Type of Nutrition
Complex single cell,
some multicellular
Absorb,
photosynthesize,
or ingest food
Representative Organisms
Protozoans,
algae, water molds,
and slime molds
paramecium
Fungi
Some unicellular,
most multicellular
filamentous forms
with specialized
complex cells
euglenoid
Multicellular form
with specialized
complex cells
Molds, yeasts,
and mushrooms
Multicellular form
with specialized
complex cells
yeast
mushroom
bracket fungus
Photosynthesize
food
moss
Animalia
dinoflagellate
Absorb food
black bread mold
Plantae
slime mold
fern
pine tree
nonwoody
flowering plant
Invertebrates,
fishes, reptiles,
amphibians, birds,
and mammals
Ingest food
Figure 1.5
Mosses, ferns,
nonwoody and
woody flowering
plants
sea star
earthworm
finch
raccoon
c. Eukaryotes are divided into four kingdoms.
(bacteria): © A.B. Dowsett/SPL/Photo Researchers, Inc.; (archaean): © Ralph Robinson/Visuals Unlimited
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Categories of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Most inclusive
Least inclusive
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Categories of Classification
• Systematics helps biologists better
understand the variety of life on Earth.
• Organisms are classified according to their
presumed evolutionary relationships.
• Systematists now perform experiments
that may result in changes in the current
classification system.
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Categories of Classification
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Scientific Names
• Taxonomy is the assignment of a
binomial to each species.
• Binomial (two name)
– Genus name, species name
– Genus capitalized, both words in italics
–Examples:
»Homo sapiens
»Pisum sativum
»Felis domesticus
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1.3 The Organization of the
Biosphere
• Biosphere
– The zone of air, land, and water at the surface
of the Earth where living organisms are found
• Population
– All the members of a species within a particular
area
• Community
– All the different populations in the same area
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The Organization of the
Biosphere
• Ecosystem
– Community interact among themselves & with
the physical environment (soil, atmosphere,
etc.)
– Characteristics
• Chemical cycling – chemicals move from one
species to another
• Energy flow – energy flows from the sun, through
plants, through the food chain
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heat
solar
energy
heat
heat
heat
heat
heat
WASTE MATERIAL,DEATH,
AND DECOMPOSITION
Chemical cycling
Energy flow
Figure 1.6
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Ecosystems
• Climate largely determines where different
ecosystems are found around the globe.
• The two most biologically diverse ecosystems—
tropical rain forests and coral reefs—occur
where solar energy is most abundant.
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great
barracuda
attached
algae
white shark
green
moray
yellowtail
snapper
yellow
jack
Spanish
hogfish
foureye
butterfly fish
corals
bar jack
queen angelfish
sponges
parrotfish
Bermuda
chub
surgeonfish
yellowtail
damselfish
Figure 1.7
sea
urchin
spiny
lobster
phytoplankton
sea
star
zooplankton
detritus
sea grass
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The Human Species
• The human species tends to modify existing
ecosystems for its own purposes.
• Tropical rain forests and coral reefs are
severely threatened as global human
population increases.
• Humans depend on healthy ecosystems for
food, medicine, and raw materials.
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Biodiversity
• Encompasses
– Total number of species
– The variability in their genes
– The ecosystems in which they live
• As many as 5-30 million species exist on
Earth.
• Human activities cause the extinction of
about 400 species per day.
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1.4 The Process of Science
• Biology is the scientific study of life.
• Biologists—and all scientists—generally
test hypotheses using the scientific
method.
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Observation
New observations
are made, and previous
data are studied.
Hypothesis
Input from various sources
is used to formulate a
testable statement.
Experiment/Observations
The hypothesis is
tested by experiment
or further observations.
Conclusion
The results are analyzed,
and the hypothesis is
supported or rejected.
Scientific Theory
Many experiments and
observations support a
theory.
© Photo by Ron Nichols, USDA Natural Resources Conservation Service
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Observation
• Scientists tend to be curious about nature
and how the world works.
• Natural phenomena may be better
understood by observing and studying them.
• Scientist use their senses to make
observations.
• They can extend their abilities by using
instruments.
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Hypothesis
• Inductive reasoning occurs when one
uses creative thinking to combine isolated
facts into a cohesive whole.
– A scientist states a hypothesis, a tentative
explanation for the natural event.
– It is presented as a falsifiable statement.
– Personal experiences may influence their
hypothesis.
– Hypotheses should be testable.
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Experiment/Further Observations
• To determine how to test a hypothesis,
scientists use deductive reasoning
– Involves “if, then” logic
• For example, a scientist might reason, if
organisms are composed of cells, then
examination of an organism should reveal
cells.
• One can also imply that the scientist has
made a prediction.
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Experiment/Further
Observations
• To test their hypothesis, scientists conduct
experiments.
• Experimental design is the manner in
which a scientist intends to conduct an
experiment.
• Experimenter should ensure that testing is
specific and the results will be meaningful.
• A control should be included in the
experiment.
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Experiment/Further
Observations
• Scientists often use a model, a representation
of an actual subject.
• For example:
– Computer modeling to study climate changes
– Mice to perform cancer research
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Data
• Data represent the results of an experiment.
– Should be observable and objective
– Should not be subjective or opinion-based
• Mathematical data is displayed as table
and/or graph.
• Statistical data is used to rule out that
results were due to chance.
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Conclusion
• A conclusion is the analysis of the data to
determine if the hypothesis can be
supported or not.
• The conclusion from one experiment may be
used to form a hypothesis for another
experiment.
• If the results do not support the hypothesis,
then it may be used to formulate an
alternate hypothesis.
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Scientific Theory
• Scientific theories are concepts that join
together well-supported and related
hypotheses.
• In science, a theory is supported by a broad
range of observations, experiments, and
data.
– Examples: cell , homeostasis, gene, ecosystem,
and evolution
• The theory of evolution is the unifying
concept of biology.
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A Controlled Study
• Experiments in controlled studies have two
types of groups:
• Control Group – receives no treatment
• Experimental Group – receives treatment
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Experimental Variable
(Independent Variable)
Response Variable
(Dependent Variable)
Factor of the experiment
being tested
Result or change that occurs
due to the experimental variable
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A Controlled Study
• Experimental background:
– nitrogen fertilizers increase crop yields in the
short term;
– continued use can cause pollution, as well as
alter soil properties;
– altered soil properties lead to reduced crop
yields;
– one solution is to leave the land unplanted for
several years.
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A Controlled Study
• Experimental background:
– An alternate to nitrogen fertilizers is to use
legumes, such as peas or beans.
– These plants allow the growth of bacteria on
their root nodules.
– These bacteria convert atmospheric nitrogen
to a form usable to plants.
– These legume crops can be rotated with
cereal crops to increase yield.
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The Experiment
• HYPOTHESIS: A pigeon pea/winter wheat
rotation will cause winter wheat production to
increase, as well as, or better than, nitrogen
fertilizer.
• PREDICTION: Wheat production (biomass)
following the growth of pigeon peas will surpass
wheat biomass following nitrogen fertilizer
treatment.
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The Experiment
• Control Pots
– Winter wheat with no nitrogen fertilizer or
legume preplanting
• Test Pots
– Winter wheat in soil treated with nitrogen fertilizer
(45kg/ha)
– Winter wheat in soil treated with nitrogen fertilizer
(90kg/ha)
– Pigeon pea plants tilled into soil and then winter
wheat planted
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Control pot
Test pot
Test pot
no fertilization treatment
90 kg of nitrogen/ha
Pigeon pea/winter wheat rotation
a. Control pot and three
types of test pots
Test pot
45 kg of nitrogen/ha
Courtesy Jim Bidlack
Figure 1.10a
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The Experiment
• All other conditions were kept the same in
all pots.
– Exposed to same environmental conditions
– Watered equally
• The following spring, wheat plants were
dried and weighed.
• Biomass was determined.
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Wheat Biomass (grams/pot)
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Control Pots
= no fertilization treatment
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Test Pots
= 45 kg of nitrogen/ha
= 90 kg of nitrogen/ha
= Pigeon pea/winter wheat rotation
10
5
0
year 1
year 2
year 3
b. Results
Figure 1.10b
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Control pot
Test pot
Test pot
no fertilization treatment
90 kg of nitrogen/ha
Pigeon pea/winter wheat rotation
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a. Control pot and three
types of test pots
Test pot
45 kg of nitrogen/ha
Wheat Biomass (grams/pot)
Control Pots
= no fertilization treatment
15
Test Pots
= 45 kg of nitrogen/ha
= 90 kg of nitrogen/ha
= Pigeon pea/winter wheat rotation
10
5
0
year 1
Figure 1.10
year 2
year 3
b. Results
Courtesy Jim Bidlack
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The Experiment
• The results after one year:
– Wheat biomass was higher in test pots than control
pots.
– Pots with 45kg/ha of fertilizer had only slighter higher
biomass.
– Pots with 90kg/ha of fertilizer had nearly twice the
biomass as control.
– Pots with pigeon pea plants tilled into soil and then
winter wheat planted did not have a biomass greater
than control pots.
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Continuing The Experiment
• The Results after Two Years:
– Conclusion: The hypothesis was supported.
– At the end of two years, the yield of winter
wheat following a pigeon pea/winter wheat
rotation was better than for the other type pots.
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Continuing The Experiment
• The Results after Three Years:
– Winter wheat biomass decreased in both the
control pots and pots treated with nitrogen
fertilizer.
– Pots with fertilizer still had more wheat
biomass than control pots.
– Wheat biomass increased almost fourfold in
pots pea/wheat rotation.
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Ecological Importance of Study
• The use of legumes long-term was more
effective in wheat biomass production than
the use of nitrogen fertilizer.
• This study represents a form of organic
gardening which not only increased yield,
but also reduced pollution.
• Organic farming may benefit farmers and
the environment.
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1.5 Science and Social
Responsibility
• Technology is the application of knowledge for
a practical purpose.
• Technology has both benefits and drawbacks
• Ethical and moral issues surrounding the use of
technology must be decided by everyone.
– Responsibility for how to use scientific technology
must reside with people from all walks of life, not with
scientists alone.
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