Introduction to Biological Concepts and Research
Chapter 1
1.1 What Is Life? Characteristics of Living Systems
Organized in a hierarchy• Each level with its own emergent properties
Contain chemical instructions• Govern structure and function
Engage in metabolic activities
1.1 (cont.)
Energy flows through; matter cycles
Compensate for changes in external environment
Reproduce and undergo development
Populations change from one generation to the next
Living Organisms
Fig. 1-1, p. 2
Hierarchy of Living Systems (1)
Cells• Lowest level of organization that is alive
Organisms• Unicellular or multicellular
Populations• Groups of organisms of the same kind, living
together in the same area
Hierarchy of Living Systems (2)
Community• All populations living in an area
Ecosystems • Include communities that interact through their
shared physical environment
Biosphere• The highest level
• Includes all Earth’s ecosystems
Hierarchy of Life
Fig. 1-2, p. 3
BiosphereAll regions of Earth’s crust, waters, andatmosphere that sustain life
Fig. 1-2, p. 3
Stepped Art
EcosystemGroup of communities interacting with their shared physical environment
CommunityPopulations of all species that occupy the same area
PopulationGroup of individuals of the same kind (that is, the same species) that occupy the same area
Multicellular OrganismIndividual consisting of interdependent cells
CellSmallest unit with the capacity to live and reproduce, independently or as part of a multi-cellular organism
Fig. 1-2a, p. 3
Cell
Smallest unit with thecapacity to live andreproduce, independentlyor as part of a multi-cellular organism
Fig. 1-2b, p. 3
Multicellular organism
Individual consisting ofinterdependent cells
Fig. 1-2c, p. 3
Population
Group of individuals ofthe same kind (that is,the same species) thatoccupy the same area
Fig. 1-2d, p. 3
Community
Populations of allspecies that occupythe same area
Fig. 1-2e, p. 3
Ecosystem
Group of communitiesinteracting with theirshared physicalenvironment
Fig. 1-2f, p. 3
Biosphere
All regions of Earth’scrust, waters, andatmosphere thatsustain life
Animation: Life’s levels of organization
Information Flow
Living organisms have complex structures• Established by instructions coded in DNA
Information in DNA is copied into RNA• Guides production of protein molecules
Proteins carry out most activities of life
Deoxyribonucleic Acid (DNA)
Fig. 1-3, p. 3
Information Flow
Fig. 1-4, p. 4
Fig. 1-4, p. 4
Information isstored in DNA.
ProteinRNADNA
The information inRNA guides theproduction of proteins.
The informationin DNA is copiedinto RNA.
Metabolism
The activity of obtaining and using energy• Maintenance
• Growth
• Reproduction
Two primary metabolic processes• Photosynthesis
• Cellular respiration
Energy and Matter
Energy• Flows through the hierarchy of life
• Eventually released as heat, which cannot be used by living systems
Matter• Recycled within the biosphere
Metabolism
Fig. 1-5, p. 4
Fig. 1-5, p. 4
Electromagneticenergy in sunlight
Energy is stored aschemical energy.
Sugar Oxygen
Cellular respirationreleases chemical energy from sugar
molecules.
Released chemicalenergy is madeavailable for othermetabolic processes.
Carbon dioxide
Waterand
Photosynthesis captures
electromagnetic energyfrom sunlight.
Oxygen
Oxygen
Cellular respirationreleases chemical energy
from sugar molecules.
Electromagneticenergy in sunlight
Photosynthesis captureselectromagnetic energy
from sunlight.
Energy is stored aschemical energy.
Sugar
Carbon dioxide
Water
and
Oxygen
Fig. 1-5, p. 4
Released chemicalenergy is madeavailable for othermetabolic processes.
Stepped Art
Compensation for Change
Cells and organisms use receptors to detect changes in environment
Triggers a compensating reaction that allows the organism to survive
Reproduction and Development
Organisms reproduce
Offspring develop into mature, reproductive adults
Evolution
Populations undergo biological evolution as generations replace one another over time
Energy Flow and Nutrient Recycling
Fig. 1-6, p. 5
Fig. 1-6, p. 5
Secondary Consumers
Heat Heat
Heat
Heat Heat
Decomposers Primary consumers
NutrientsrecycledSun
Primary Producers
Energy ultimatelylost as heatEnergy transfer
KEY
1.2 Biological Evolution
Darwin and Wallace explained how populations of organisms change through time
Mutations in DNA allow evolutionary change
Adaptations enable organisms to survive and reproduce in their environments
Populations Change With Time (1)
Changes occur in structure, function, types of organisms
Theory of evolution by natural selection• Certain characteristics allow some organisms to
survive better and reproduce more than others in their population
Populations Change With Time (2)
Instructions for characteristics are coded in DNA• Successful characteristics become more common
in later generations
Average characteristics of offspring generation differ from those of parent generation
Life Cycle: Silkworm Moth
Fig. 1-7, p. 6
Fig. 1-7, p. 6
e. Adulta. Egg b. Larva c. Pupa
d. Recentlyemerged adult
Animation: One-way energy flow and materials cycling
Heredity (1)
Genes• Segments of DNA
• Code instructions for many characteristics
• Passed through reproduction from parents to offspring
Heredity (2)
Mutations• Changes in structure, number, or arrangement of
DNA molecules
• Create variability among individuals
Variability• Natural selection and other processes cause
biological evolution
Adaptations
Accumulation of favorable characteristics over many generations may produce adaptations
Enable individuals to survive longer or reproduce more
Artificial Selection
Fig. 1-8, p. 7
Animation: Insect development
Camouflage in Rock Pocket Mice
Fig. 1-9, p. 8
Distributions of Rock Pocket Mice
Fig. 1-10, p. 9
Fig. 1-10, p. 9
New MexicoArizona
Mouse colorArmendarisPinacate
N = 8N = 12N = 5N = 15N = 11N = 18
Rock colorMost mice captured on pale rockshad sandy-colored fur.
Most mice captured on dark rocks had black fur.
Diversity of Life on Earth
Produced by accumulation of adaptations and other genetic differences between populations over long spans of time
1.3 Biodiversity
Species • Closely related populations that can interbreed
Biologists classify organisms into three domains and several kingdoms
Hierarchy of Classification
Species Genus Family Order Class Phylum Kingdom
Classification
Fig. 1-11, p. 10
Fig. 1-11, p. 10
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Canis
Species: Canis familiaris
Phylum: Chordata
Class: Mammalia
Domain: Eukarya
Kingdom: Animalia
Order: Carnivora
Family: Canidae
Genus: Canis
Species: Canis familiaris
Fig. 1-11, p. 10
Stepped Art
Domains
Biologists organize kingdoms into 3 domains based on characteristics of cell structure • Bacteria
• Archaea
• Eukarya
3 Domains of Life
Fig. 1-13, p. 12
Fig. 1-13, p. 12
a. Domain Bacteria
b. Domain Archaea
c. Domain EukaryaKingdom Protoctista Kingdom Fungi
Kingdom AnimaliaKingdom Plantae
Kingdoms
Bacteria and Archaea each include one kingdom
Eukarya is divided into four kingdoms: • Protoctista
• Plantae
• Fungi
• Animalia
Prokaryotes and Eukaryotes
Fig. 1-12, p. 11
Fig. 1-12a, p. 11
DNA
a. Escherichia coli, a prokaryote
Fig. 1-12b, p. 11
Nucleus with DNA
b. Paramecium aurelia, a eukaryote
1.4 Biological Research
Biologists conduct basic and applied research using the scientific method
Research includes collecting observational and experimental data
Hypotheses may be tested with controlled experiments
Or, a null hypotheses may be used to evaluate observational data
1.4 (cont.)
Model organisms may be used to study fundamental biological processes
Molecular techniques have revolutionized biological research
Scientific theories are ideas that have withstood the test of time
Basic and Applied Research
Basic research advances our knowledge of living systems
Applied research solves practical problems
Data
Observational data describe biological organisms or the details of biological processes
Experimental data describe results of an experimental manipulation
Hypotheses
Working explanations developed by scientists about the relationships between variables
Scientific hypotheses must be falsifiable
Experiment
A well-designed experiment• Considers alternative hypotheses
• Includes control treatments and replicates
Experimental Research
Fig. 1-14, p. 15
Fig. 1-14a (1), p. 15
Fig. 1-14a (2), p. 15
Fig. 1-14b, p. 15
Animation: Life’s diversity
Null Hypotheses
Explanations of what scientists would see if their hypothesis was wrong
Used to evaluate observational or experimental data when experiments are unfeasible
Observational Research
Fig. 1-15de, p. 17
Fig. 1-15a, p. 17
Anolis gundlachi
Fig. 1-15b, p. 17
Anolis cristatellus
Fig. 1-15c, p. 17
Copper Anolis model
Fig. 1-15d, p. 17
Percentage of models and lizards perched in sun or shade
In the forest where A. gundlachi lives,nearly all models and nearly all lizards perched in shade.
Per
cen
tag
e in
su
n o
r sh
ade
LizardsModels LizardsModelsPer
cen
tag
e in
su
n o
r sh
ade
Perched in sun
Perched in shade
In the habitat where A. cristatellus lives,nearly all modelsperched in shade, but most lizards perched in sun.
Anolis gundlachi Anolis cristatellus
Fig. 1-15e, p. 17
Temperatures of models and lizards
Lizards
Models
Lizards
Models
Per
cen
tag
e o
f o
bse
rvat
ion
s
Per
cen
tag
e o
f o
bse
rvat
ion
sTemperature (°C) Temperature (°C)
Body temperaturesof A. gundlachi were not significantlydifferent from those of the randomly placed models.
Body temperaturesof A. cristatellus were significantly higher than those of the randomly placed models.
Anolis gundlachi Anolis cristatellus
Animation: Sample size and accuracy
Modern Techniques
Model organisms• Easy to maintain in the laboratory
• Subjects of much research
Molecular techniques• Manipulation of specific genes in the laboratory
• Allow detailed analysis of DNA of many species
A Scientific Theory
A set of broadly applicable hypotheses• Completely supported by repeated tests under
many conditions and different situations
Theory of evolution by natural selection• Explains how life evolved through natural
processes
• Central importance to biology
Animation: How do scientists use random samples to test hypotheses
Video: Bird flu
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