Transcript Chapter 1 – Exploring Life

Principles of Biology BIO 101
Prof. Marianne E. McNamara
Who Are You?
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Your major
Your year/are you part time or full time
Your plans
Your interests
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
Why Study Biology???
• It’s EVERYWHERE!
Why Study Biology???
• Biology frequently plays a role in dealing
with various challenges that face society
Why Study Biology???
• It’s AWESOME!!!
http://dsc.discovery.com/videos/planet-earth-highlights/
Why Study Biology???
• Biology is the scientific study of life!
http://www.croski.hr/fotogalerija/20021207200152slc2.jpg
www.luttyphoto.com
http://www.mnh.si.edu/exhibits/natures_best_2006/gallery/sno
wmonkeyandbaby.html
What is the definition of life?
• Life is a characteristic shared by ‘objects’
with self-sustaining biological processes
• All living things share these characteristics:
– Organization
– Metabolism (growth and development)
– Reproduction
– Interaction/response to their environment
– Evolutionary adaptation
– 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
Hierarchy of
Life
Ecosystem
Florida coast
Level
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
• Ecosystem
• Community
• Population
• Organisms
• Systems
• Organs
• Tissues
• Cells
• Molecules
• Atoms
Molecule
DNA
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 over a long
period of time (most of the 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 (we’ll
come back to this)
6. Genetic component (DNA)
• All living organisms have
DNA as their genetic blueprint
• DNA = deoxyribonucleic acid
• Every cell uses DNA as its
genetic information
• Every species has its own
unique DNA sequence.
Three domains of life
• Organisms can be grouped into three
domains
• Scientists classify organisms into a
hierarchy of groups
– Grouped by fundamental characteristics
– Helps scientists manage the great diversity of
life for study
– 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
– Domain Eubacteria
– Domain Eukarya
Prokaryotic
Eukaryotic
Eukaryote = genetic material stored in a
nucleus
Prokaryote = no nucleus; genetic
material ‘loose’ in cell
Classification
• Domains are further classified/categorized
into:
– Kingdom
– Phylum
– Class
– Order
– Family
– Genus
– Species
Domain
Kingdom
Phylum
Subphylum
Class
Order
Family
Diversification
Genus
Species
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
Scientific name
• Why all the fuss? Common names can be
deceiving…
“dolphin”
“bear”
http://www.ticam.utexas.edu/images/grizzly.jpg
Scientific name
• Scientific names are descriptive
• May describe unique characteristic, region
where species is found, etc.
• Example: Humpback whale Megaptera
novaeangliae
– Magas = large
– Pteron = wing
– Novas = new
– Angaliae = England
Scientific Method
• A systematic approach to understand the
natural world
– Observation
– Hypothesis
• Must be testable
– Experimentation
• Must be repeatable
• Multiple trials necessary
– Conclusion
• Supports or rejects the hypothesis
Hypotheses can never be proven!!!