chapter 1: exploring life. history is a vital tool in learning about science. louis pastuer charles...
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Chapter 1:
Exploring Life
History is a vital tool in learning about science.
Louis Pastuer Charles Darwin
Figure 1.1
Biology is the science that focuses on life
Figure 1.3
Order
Evolutionary adaptation
Response tothe environment
Reproduction
Growth anddevelopment
Energy processing
Regulation
Exploring Levels of Biological Organization1 The biosphere
2 Ecosystems
3 Communities
4 Populations
5 Organisms
8 Cells
6 Organs and organ systems
7 Tissues
10 Molecules
9 Organelles
50 µm
10 µm
1 µmCell
Atoms
Basic scheme for energy flow through an ecosystem
Figure 1.5Leaves take incarbon dioxide
from the airand release
oxygen.
Animals eatleaves and fruitfrom the tree.
Sunlight
CO2
O2
Cyclingof
chemicalnutrients
Leaves fall tothe ground and
are decomposedby organisms
that returnminerals to the
soil.
Water andminerals inthe soil aretaken up by
the treethroughits roots.
Leaves absorblight energy from
the sun.
Inherited DNA directs development of an organism
Sperm cell
NucleicontainingDNA
Egg cell
Fertilized eggwith DNA fromboth parents
Embyro’s cells with copies of inherited DNA
Offspring with traitsinherited fromboth parents
Figure 1.10
DNA: The genetic materialNucleus
DNA
Cell
Nucleotide
A
C
T
A
T
A
C
C
G
G
T
A
T
A
(b) Single strand of DNA. These geometric shapes and letters are simple symbols for the nucleotides in a small section of one chain of a DNA molecule. Genetic information is encoded in specific sequences of the four types of nucleotides (their names are abbreviated here as A, T, C, and G).
(a) DNA double helix. This model shows each atom in a segment of DNA. Made up of two long chains of building blocks called nucleotides, a DNA molecule takes the three-dimensional form of a double helix.
Contrasting eukaryotic and prokaryotic cells in size and complexity
Figure 1.8
Eukaryotic cellProkaryotic cell
Cytoplasm
DNA(no nucleus)
Membrane
Nucleus(membrane-enclosed)
Membrane
Membrane-enclosed organelles
DNA (throughoutnucleus) 1 m
Modern biology as an information science
Figure 1.13
Negativefeedback
A
B
C
D
C
Enzyme 1
Enzyme 2
Enzyme 3
D
W
Enzyme 4
X
DD
Excess Dblocks a step.
(a) Negative feedback
Positive feedback
Excess Zstimulates a step.
Y
Z
Z
Z
Z
(b) Positive feedback
Enzyme 5
Enzyme 6
Drawers of diversity
Classifying lifeSpecies Genus Family Order Class Phylum Kingdom Domain
Mammalia
Ursusameri-canus(Americanblack bear)
Ursus
Ursidae
Carnivora
Chordata
Animalia
Eukarya
Exploring Life’s Three Domains
(a) Domain Bacteria (b) Domain Archaea
(c) Domain Eukarya
2 m
2 m
100 m
Kingdom Plantae
Kingdom Fungi
Protists
Kingdom Animalia
An example of unity underlying the diversity of life: the architecture of cilia in eukaryotes
Cilia of Paramecium.The cilia of Parameciumpropel the cell throughpond water.
Cross section of cilium, as viewedwith an electron microscope
15 µm
1.0 µm
5 µm
Cilia of windpipe cells. The cells that line the human windpipe are equipped with cilia that help keep the lungs clean by moving afilm of debris-trapping mucus upward.
Digging into the past
Charles Darwin in 1859, the year he published The Origin of Species
Unity and diversity in the orchid family
Summary of natural selection
Populationof organisms
Hereditaryvariations
Differences in reproductive success
Evolution of adaptationsin the population
Overproductionand struggle forexistence
Natural selection
1 Populations with varied inherited traits
2 Elimination of individuals with certain traits.
3 Reproduction of survivors.
4 Increasing frequency of traits that enhance survival and reproductive success.
Form fits function
Descent with modification: adaptive radiation of finches on the Galápagos Islands
Figure 1.22
COMMONANCESTOR
Green warbler finchCerthidea olivacea
Gray warbler finchCerthidea fusca
Sharp-beakedground finch
Geospiza difficilisVegetarian finch
Platyspiza crassirostris
Mangrove finchCactospiza heliobates
Woodpecker finchCactospiza pallida
Medium tree finchCamarhynchus pauper
Large tree finchCamarhynchus psittacula
Small tree finchCamarhynchus parvulus
Large cactusground finch
Geospiza conirostrisCactus ground finchGeospiza scandens
Small ground finchGeospiza fuliginosa
Medium ground finchGeospiza fortis
Large ground finchGeospiza
magnirostris
Inse
ct-e
aters
See
d-e
ater
Bu
d-e
ate
r
Inse
ct-e
aters
Tree
finc
he
sG
rou
nd
finch
es
See
d-e
aters
Cac
tus
-flow
er-
ea
ters
Warb
ler fin
ch
es
A campground example of hypothesis-based inquiry
Observations
Questions
Hypothesis # 1:Dead batteries
Hypothesis # 2:Burnt-out bulb
Prediction:Replacing batterieswill fix problem
Prediction:Replacing bulbwill fix problem
Test prediction
Test does not falsify hypothesis
Test prediction
Test falsifies hypothesis
Figure 1.23
A stinging honeybee and its nonstinging mimic, a flower fly
Flower fly(non-stinging)
Honeybee (stinging)
Science as a social process
Eleven Themes that Unify Biology