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Biology
9/15-10/21 (6 weeks)
授課老師:蔡玉真
電話分機: 2468, 2469
生命科學系 107室
Office time: Tuesday 1:00-3:00
Biology
Seventh edition
Neil A.Campbell and Jane B.Reece
Exploring life (1)
The chemistry of life (2-5)
The cell (6-10)
Bird’s nest fern
(Fiddlehead fern)
mid-term exam (2): 70%
Quiz: 20%
出席率: 10%
Score: 33.3分
Exploring Life
Biology is the scientific study of life
How do we recognize life? By what ?
Growth
Reproduce similar organisms
properties of life
(b) Evolutionary
adaptation
(a) Order
(c) Response to the
environment
(d) Regulation
(e) Energy
processing
(f) Growth and
development
(g) Reproduction
Biologists explore life from the microscopic to the global scale
A Hierarchy of Biological Organization:
• microscope scale of molecules and cells
• organisms
• the global scale of the entire living planet
many levels of biological organization
biosphere
Ecosystems
Livings and non-living
communities
livings
population
organisms
from the biosphere to organisms
From cells to molecules
Organelles
1 µm
Molecules
Cells
Atoms
10 µm
Tissues
50 µm
Organs and organ systems
The cell is the lowest level of organization that can
perform all activities required for life
DNA
spindle
cell division
mitosis
25 µm
cell
Cell theory:
• 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
– Eukaryotic
– Prokaryotic
nuclear
cell
Eukaryotic cells vs. Prokaryotic cells
EUKARYOTIC CELL
PROKARYOTIC CELL
DNA
(no nucleus)
Membrane
Membrane
Cytoplasm
cell
Organelles
size
Nucleus (contains DNA)
membrane-enclosed organelles
1 µm
Lack of membrane-enclosed organelles
The Cell’s Heritable Information : DNA
-program the cells’ production of proteins
-transmit information from parents to offspring
inheritance
Sperm cell
Nuclei
containing
DNA
Egg cell
Fertilized egg
with DNA from
both parents
Embyro’s cells
with copies of
inherited DNA
Offspring with traits
inherited from
both parents
DNA
The molecular structure of DNA
Deoxyribonucleic acid (DNA)
Nucleus
DNA
Cell
A
C
Nucleotide
T
A
T
four types of nucleotides
(A, T, C, and G).
A
C
C
G
T
A
G
T
A
DNA double helix
Single strand of DNA.
DNA
Energy flows through an ecosystem
Sunlight
Ecosystem
Producers
(plants and other
photosynthetic
organisms)
Heat
Chemical
energy
Consumers
(including animals)
Heat
ecosystem
Usually entering as sunlight and exiting as heat
Taxonomy: Classifying life
Species Genus Family
Order
Class
Phylum Kingdom Domain
Ursus ameri-canus
(American
black bear)
Ursus
Ursidae
Carnivora
Mammalia
Chordata
Animalia
Community
Eukarya
similarity
diversity
The Three Domains of Life
At the highest level, life is classified into three domains
Bacteria
Consist of prokaryotes
Archaea
Eukarya
the eukaryotes
Includes the various protist kingdoms
and the kingdoms Plantae, Fungi, and Animalia
Life’s three domains
protist
4 µm
100 µm
Plantae,
DOMAIN ARCHAEA
0.5
µm
0.5µm
Fungi
Animalia
Remarkable unity in the Diversity of Life
15 µm
Universal genetic language:
DNA
Cilia of Paramecium.
Eukaryotic cell structure
The cilia of Paramecium
propel the cell through
pond water.
1.0 µm
9+2
5 µm
Cross section of cilium,
as viewed with an electron
microscope
Cilia of windpipe cells.
The cells that keep the lungs clean
by moving a film of debris-trapping
mucus upward.
The evolutionary view of life
Charles Darwin published On the Origin of Species by Natural Selection
(in 1859)
Charles Darwin
organism
The Origin of Species articulated two main points
Descent with modification
-mutation
-sexual reproduction
Gametes get different combination
of parents chromosomes
Natural selection
Natural selection
1 Populations with varied inherited traits
environmental factors
2 Elimination of individuals with certain traits.
3 Reproduction of survivors.
4 Increasing frequency of traits that enhance
survival and reproductive success.
Natural Selection
Population
of organisms
Hereditary
variations
Overproduction
and struggle for
existence
Differences in
reproductive success
Evolution of adaptations
in the population
The Tree of life
Large
ground finch
Large cactus
ground finch
Small
ground
finch
similar anatomical features
Large
tree finch
Camarhynchus
Geospiza
Green
Gray
Geospiza
psitacula
magnirostris
warbler warbler
fuliginosa
Sharp-beaked
Woodpecker Medium
finch
finch
Medium
Geospiza
tree finch
ground finch
finch
conirostris ground
finch
Certhidea Certhidea
Geospiza Cactus
Cactospiza Camarhynchus olivacea fusca
difficilis ground finch
pauper
pallida
Mangrove
Geospiza
Small tree finch
finch
fortis
Geospiza
Camarhynchus
Cactospiza
scandens
parvulus
heliobates
Vegetarian
Cactus flower
Seed eater
Seed eater
finch
eater
Platyspiza
crassirostris
Insect eaters
Ground finches
Galapagos islands
Tree finches
Bud eater
Warbler finches
Common ancestor from
South American mainland
Kinship
food
niche
The products of natural selection
Are often exquisite adaptations of organisms to the special
circumstances of their way of life and their environment
bat
Structure and function
Reductionism vs. System biology
Reductionism
reducing complex systems to simpler components that are
more manageable to study
System biology
-
models of the dynamic behavior of whole biological systems
-
at the cellular and molecular levels
-
high-throughput technology, bioinformatics, and
interdisciplinary research teams
How do biologists inquiry to explore life?
A search for information and explanation, often focusing
on specific questions
Two approaches of scientific study:
Discovery science : describe nature
Hypothesis-based science: explain nature
to know
Discovery Science--Descriptive science
-describes life (at many different levels)
-careful observation and measurement
-analysis of data and get conclusions
Example: “All organisms are made of cells”
Induction reasoning
generalizations based on a large
number of specific observations
Hypotheses-based Scientific method
testable
falsifiable
Observations
specific questions
Propose
Questions
Hypothesis # 1:
Dead batteries
Prediction:
Replacing batteries
will fix problem
Test
Test prediction
Test falsifies hypothesis
Hypothesis # 2:
Burnt-out bulb
Prediction:
Replacing bulb
will fix problem
Test prediction
Test does not falsify hypothesis
Logic of Hypothesis-Based Science
• deductive
The logic flows from the general to the specific
• If a hypothesis is correct,
Then we can expect a particular outcome
Designing Controlled Experiments
control groups
experimental groups
in a way that cancels the effects of unwanted variables
Scientific method
Discovery Science : induction
Hypotheses-based Science: deduction
Limitation?
Observation and experimental results: repeatability
Hypothesis is testable and falsifiable
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Theories :
Is broad in scope than hypothesis
Generates new hypotheses
Is supported by a large body of evidence
Model :
Diagrams, graphs, 3-D objects, computer programs
or mathematical equations
Help us understand scientific phenomena and make predictions
Models of ideas, structures, and processes
• In mimicry
– A harmless species resembles a harmful
species
Advantage?
Flower fly
(non-stinging)
Honeybee (stinging)
To test this mimicry hypothesis
Field Experiments with Artificial Snakes
hundreds of artificial snakes
an experimental group
(a) Artificial king snake
a control group
(b) Brown artificial snake that has been attacked
The hypothesis predicts that predators in non–coral snake areas will
attack king snakes more frequently than will predators that live
where coral snakes are present
Scarlet king snake
Key
Range of scarlet king snake
Range of eastern color snake
North
Carolina
South
Carolina
Eastern coral snake
Scarlet king snake
After a given period of time
The researchers collected data that fit a key prediction
17%
In areas where coral snakes
were absent, most attacks
were on artificial king snakes
North
Carolina
South
Carolina
83%
X
XX
X
XX
X
X X
X XX
X
X
16%
84%
Key
In areas where coral
snakes were present,
most attacks were on
artificial brown snakes
% of attacks on artificial king snakes
% of attacks on brown artificial snakes
Field site with artificial snakes
Protein interaction map:
CELL
Outer membrane
and cell surface
Cytoplasm
Nucleus
System biology
An accumulation of an end product slows the process
that produces that product
A
A
Enzyme 1
Enzyme 1
shut down/shut-off
B
B
Enzyme 2
C
C
Enzyme 3
D
end product
D
D
D
D
D
D
D
D
D
D
The negative feedback regulation
The end product speeds up production
W
W
Enzyme 4
Enzyme 4
X
X
Enzyme 5
Enzyme 5
Y
Y
Enzyme 6
Z
Z
Z
Z
end product
Enzyme 6
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
The positive feedback regulation
Z