Chapter 1:
Biology: Exploring Life
Introduction: Dining in the Trees
• The leopard is an excellent example of an
organism adapted to its environment
– It survives because of adaptations to its
environment
– Examples are coat camouflage and hunting and climbing
ability
– Adaptations are the result of evolution
– Evolution is the process of change that transforms life
– Biology is the scientific study of life
THEMES IN THE STUDY
OF BIOLOGY
1.1 In life’s hierarchy of organization, new properties
emerge at each level
• Life’s levels of organization define the scope of
biology
– Life emerges through organization of various levels
– With addition of each new level, novel properties
emerge—called emergent properties
– Each level builds to make the next
Biosphere
Ecosystem
Florida coast
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Spinal cord
Nerve
Organ system
Nervous system
Brain
Organ
Brain
Tissue
Nervous tissue
Cell
Nerve cell
Atom
Nucleus
Organelle
Nucleus
Molecule
DNA
Biosphere
Ecosystem
Florida coast
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Organism
Brown pelican
Spinal cord
Nerve
Organ system
Nervous system
Brain
Organ
Brain
Tissue
Nervous tissue
Atom
Cell
Nerve cell
Nucleus
Organelle
Nucleus
Molecule
DNA
1.1 Life’s Hierarchy of Organization
• The upper tier is a global perspective of life
–
–
–
–
Biosphere
Ecosystem
Community
Population
Fig. 1-4c
The biosphere
Fig. 1-4d
Ecosystems
Fig. 1-4e
Communities
Fig. 1-4f
Populations
1.1 Life’s Hierarchy of Organization
• The middle tier is characterized by the organism,
an individual living thing, which is composed of
– Organ systems
– Organs
– Tissues
Fig. 1-4g
Organisms
Fig. 1-4h
Organs and
organ systems
Fig. 1-4i
Tissues
50 µm
1.1 Life’s Hierarchy of Organization
 Life emerges at the level of the cell, the lower
tier, which is composed of
– Cells
– Organelles
– Molecules
Fig. 1-4j
10 µm
Cell
Cells
Fig. 1-4k
1 µm
Organelles
Fig. 1-4l
Atoms
Molecules
1.1 Checking for Understanding
 Which of the following levels of biological
organization includes all others in the list: cell,
molecule, organ, tissue?
1.2 Living organisms interact with their environments,
exchanging matter and energy
• Life (biotic components) requires interactions
between living and nonliving components:
– Photosynthetic organisms provide food and are
called producers.
– Other organisms eat plants (or animals that profit
from plants originally) and are called consumers.
– The nonliving components (abiotic) are chemical
nutrients required for life.
1.2 Exchanging Matter and Energy
• To be successful, an ecosystem must accomplish
two things
– Recycle chemicals necessary for life
– Move energy through the ecosystem
– Energy enters as light and exits as heat
Sunlight
Ecosystem
Cycling
of
chemical
nutrients
Producers
(such as plants)
Heat
Chemical energy
Consumers
(such as animals)
Heat
1.2 Checking for Understanding
 Explain how the photosynthesis of plants
functions in both the cycling of chemical
nutrients and the flow of energy in an
ecosystem?
1.3 Cells are the structural and functional units of life
• Structure directly correlates to function
– By studying a biological structure, you determine
what it does and how it works
– Life emerges from interactions of structures
– Combinations of structures (components) provide
organization called a system
1.3 Structure directly correlates to function
• Systems Biology
• Study of how the systems will interact with each other
– Ex. Study of how a new drug will affect the systems of the body
• Construct models for behavior of entire systems
– Ex: Model of the entire biosphere
1.3 Structure directly correlates to function
• Reductionism
• Study from the small to understand the whole
– Ex. Watson/Crick/Franklin: studied structure of DNA in order to figure out
genes and chromosomes
1.3 Cells are the structural and functional units of life
• Two distinct groups of cells exist
– Prokaryotic cells
– Simple and small
– Cell membrane but NO nucleus
– Bacteria are prokaryotic
– Eukaryotic cells
– Possess organelles separated by membranes
– Nucleus
– Plants, animals, and fungi are eukaryotic
Prokaryotic cell
DNA
(no nucleus)
Membrane
Nucleus
(contains DNA)
Organelles
Eukaryotic cell
1.3 Checking for Understanding
 Why are cells considered the basic unit of life?