What is Biology?
• Biology is the study of life (bios = “life”; logia = “the
study of”)
• Biology consists of several specialized disciplines
– Botany: the study of plants
– Zoology: the study of animals
– Microbiology: the study of microorganisms
What is Life?
•
Life is a characteristic shared by ‘objects’ with selfsustaining biological processes
• All living things share these characteristics:
1. Organization
2. Metabolism (growth and development)
3. Reproduction
4. Interaction/response to their environment
5. Evolutionary adaptation
6. Genetic component (DNA)
1. Organization
• All living things are organized
• Life is organized in a hierarchical fashion
– hierarchy: any system of things ranked one above
another
Biosphere
Ecosystem
Florida coast
Hierarchy of Life
Level
• Ecosystem
Community
All organisms on
the Florida coast
• Community
• Population
• Organisms
• Systems
• Organs
• Tissues
Population
Group of brown
pelicans
Organism
Brown pelican
Spinal cord
Nerve
Organ system
Nervous system
Brain
Organ
Brain
Tissue
Nervous tissue
• Cells
Cell
Nerve cell
Atom
Nucleus
Organelle
Nucleus
Molecule
DNA
• Molecules
• Atoms
2. Metabolism
• All living things metabolize
• Metabolism = set of chemical reactions necessary to
maintain life
– Metabolism is management of ENERGY; organisms
TAKE energy from their environment, transform and
use it
– Allows organisms to grow, reproduce, maintain
structural stability, and respond to their
environments
Metabolism
• Autotrophs – transform energy from their
environment (the “producers”)
– Plants are autotrophs; they transform the sun’s
energy into energy-rich molecules that support life
• Heterotrophs – ingest their energy from their
environment (the “consumers”)
– Animals are heterotrophs; they ingest (eat) food to
obtain energy-rich molecules
3. Reproduction
• All living things reproduce
• Reproduction can be sexual,
asexual, or both!
4. Interaction/response to environment
• All living things interact and respond to their
environment
• Living things respond to environmental stimuli (scent,
sight, sound, touch, taste)
• Living things exchange gases (carbon dioxide,
oxygen, etc) with their environment
Environmental interaction
A Venus
flytrap
responds to
the stimulus of
a dragonfly
landing on it
5. Evolutionary adaptation
• All living things evolve
• Evolution is a gradual change that occurs over a long
period of time
• Evolution explains the diversity and adaptations of life
• Evolution is the change in genetic material of a
population of organisms from one generation to the
next
6. Genetic component (DNA)
• All living organisms have DNA as
their genetic blueprint
• DNA = deoxyribonucleic acid
• Every cell uses DNA as its genetic
information to provide all structural
and functional characteristics of the
organism
• Every species has its own unique
DNA blueprint.
Three Domains of Life
• Organisms can be grouped into three domains
• Scientists classify organisms into a hierarchy of
groups in order to manage the great diversity of life for
study
– Grouped by fundamental characteristics
– Not always clear-cut; organisms do not always fall
into structured categories
Three Domains of Life
• All organisms are grouped into three domains
– Domain Archea
Prokaryotic
– Domain Eubacteria
– Domain Eukarya
Eukaryotic
Prokaryote = no nucleus; genetic material ‘loose’ in
cell
Eukaryote = genetic material stored in a nucleus
Classification
• Domains are further classified/categorized into:
– Kingdom
– Phylum
– Class
– Order
– Family
– Genus
– Species
Domain
Kingdom
Phylum
Subphylum
Class
Order
Family
Genus
Species
Diversification
Scientific Name
• Organisms are ultimately sorted to the species level
(species that appear to be closely related are grouped
into the same genus)
• Binomial (“two part”) system: genus and species
constitute the scientific name of the organism
• Genus is always Capitalized and species is always
lower-case; both are in italics
– Homo sapiens
Scientific Name
• Why all the fuss? Common names can be
deceiving…
“bear”
“bear”
Scientific Method
• A systematic approach to understand the natural world
– Observation
– Hypothesis (educated guess based on observation
and previous scientific knowledge)
• must be testable
– Experimentation
• must be repeatable in order to confirm results are
not occurring by chance
– Conclusion
• supports or rejects the hypothesis