Download Biology: Exploring Life (Chapter 1)

Chapter 1
Biology: Exploring Life
PowerPoint Lectures for
Biology: Concepts and Connections, Fifth Edition
– Campbell, Reece, Taylor, and Simon
Lectures by Chris Romero
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
THE SCOPE OF BIOLOGY
1.1 Life’s levels of organization define the scope of biology
• Life’s structural hierarchy
–
Defines the scope of biology, the scientific
study of life
Biosphere
Ecosystem
Florida coast
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Spinal cord
Organ system
Nervous system
Brain
Nerve
Organ
Brain
Tissue
Nervous tissue
Figure 1.1
Cell
Nerve cell
Nucleus
Organelle
Nucleus
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Atom
Molecule
DNA
• An ecosystem consists of all the organisms
living in a particular area
– As well as the nonliving environmental
components
• All the living organisms in an ecosystem
– Make up a community
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• A population
– Consists of a localized group of
individuals of a species
• An individual living entity
– Is an organism
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• The hierarchy continues downward with
– Organ systems
– Organs
– Tissues
– Cells
– Organelles
– Molecules
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1.2 Living organisms and their environments form
interconnecting webs
• Ecosystems are characterized by the cycling of
chemical nutrients from the atmosphere and
soil
– To producers to consumers to
decomposers and back to the
environment
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• Energy flows one-way through an ecosystem
– From the sun to producers to consumers
and exits as heat
Sun
Air
Inflow
of
light
energy
O2
CO2
CO2
Chemical
energy
Producers
Cycling
of
Chemical
nutrients
Decomposers
H2O
Figure 1.2
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Consumers
Soil
Ecosystem
Loss
of
heat
energy
1.3 Cells are the structural and functional units of life
• A cell
–
Is the basic unit of life
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• New properties emerge
– From the complex organization of a
system, such as a cell
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• Eukaryotic cells
–
Contain membrane-enclosed organelles,
including a DNA-containing nucleus
• Prokaryotic cells
–
Lack such organelles
Nucleus
(contains DNA)
Prokaryotic cell
Eukaryotic
cell
DNA
(no nucleus)
Figure 1.3
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25,000 
Organelles
EVOLUTION, UNITY, AND DIVERSITY
1.4 The unity of life: All forms of life have
common features
• DNA is the genetic information
– For constructing the molecules that make
up cells and organisms
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• Each species’ genetic instructions
–
Are coded in the sequences of the four building
blocks making up DNA’s two helically coiled chains
A
C
T
A
T
A
C
C
G
T
A
G
T
Figure 1.4A
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A
• All organisms share a common set of features
–
Ordered structures
–
Regulation of internal conditions
Figure 1.4B
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Figure 1.4C
Figure 1.4D
–
Growth and development
–
Energy use
–
Response to environmental stimuli
–
The ability to reproduce and evolve
Figure 1.4E
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1.5 The diversity of life can be arranged into
three domains
• Organisms are grouped (classified)
– Into the prokaryotic domains Bacteria
and Archaea and the eukaryotic domain
Eukarya
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SEM 3,250
• Domains Bacteria and Archaea
SEM 25,000
Figure 1.5A
Figure 1.5B
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• Domain Eukarya includes
–
Protists (protozoans and algae, falling into
multiple kingdoms)
–
The kingdoms Fungi, Plantae, and Animalia
275
Kingdom Fungi
Kingdom Animalia
Protists
(multiple kingdoms)
Figure 1.5C
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Kingdom
Plantae
1.6 Evolution explains the unity and diversity of life
• Charles Darwin
– Developed the theory of evolution by
natural selection
Figure 1.6A
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• Natural selection is an editing mechanism
–
Occurs when populations or organisms, having
inherited variations, are exposed to environmental
factors that favor the reproductive success of
some individuals over others
1 Populations with varied inherited traits
2 Elimination of individuals with certain traits
Figure 1.6B
3 Reproduction of survivors
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• All organisms have adaptations
–
Have evolved by means of natural selection
Killer whale
Pangolin
Figure 1.6C
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THE PROCESS OF SCIENCE
1.7 Scientists use two main approaches to learn
about nature
• Science
– Is a way of knowing
– Seeks natural causes for natural
phenomena
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Hypothesis-Based Science
• In hypothesis-based science
– Scientists attempt to explain
observations by testing hypotheses
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1.8 With hypothesis-based science, we pose and
test hypotheses
• Hypothesis-based science involves
– Observations, questions, hypotheses as
possible explanations/answers to
questions
– Deductions leading to predictions, and
then tests of predictions to see if a
hypothesis can be disproved
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A Case Study from Everyday Life
• Deductive reasoning is used in testing hypotheses as follows
–
If a hypothesis is correct, and we test it, then we can
expect a particular outcome
Observations
Question
Figure 1.8A
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Hypothesis # 1:
Dead batteries
Hypothesis # 2:
Burnt-out bulb
Prediction:
Replacing batteries
will fix problem
Prediction:
Replacing bulb
will fix problem
Test prediction
Test prediction
Test disproves hypothesis
Test does not disprove hypothesis
A Case Study of Hypothesis-Based Science
• In experiments designed to test hypotheses
–
The use of control groups and experimental
groups helps to control variables
100
84%
Figure 1.8B
Figure 1.8C
Percent of total attacks
on artificial snakes
83%
80
Artificial brown snakes
60
40
20
17%
16%
0
Coral snakes
absent
Figure 1.8E
Figure 1.8D
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Artificial king snakes
Coral snakes
present
BIOLOGY AND EVERYDAY LIFE CONNECTION
1.8 Biology is connected to our lives in many ways
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• Biology is connected to many important issues in
our lives
–
Environmental problems and solutions
–
Genetic engineering
–
Medicine
Figure 1.9
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• Many technological advances
– Stem from scientific research
• The science-technology-society relationship
– Is an important aspect of a biology
course
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