Transcript Exploring Life

EXPLORING LIFE
Chapter 1
WHAT IS THE SCIENCE OF BIOLOGY?
 Biology
 Scientific
is the study of life
inquiry is key
 Asking questions about living organisms
and deriving scientifically supported
answers
 What makes a living organism?
 Seven characteristics are used by scientists
to define life
 Neither inclusive or exclusive
 LIMITATIONS EXIST
LIFE’S COMMON FEATURES
LIMITATIONS EXIST
HIERARCHICAL CLASSIFICATION OF LIFE
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Biosphere – all regions of Earth the support life
Ecosystems – all living and non-living organisms in an area
Communities – all species living in one area
Populations – individuals of a species in a specific area
Multi-celled organisms – each living individual in an area
Organ systems – 2+ organs interacting to enhance survival
Organs – body part with 2+ tissues performing common tasks
Tissues – cells working together for a specialized activity
Cells – smallest unit able to demonstrate characteristics of life
Organelles – internal compartments of cells for specialized
reactions
Molecules – 2 or more atoms bonded together
THE WHOLE IS MORE THAN THE SUM OF ITS PARTS
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Emergent properties
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Novel properties emerge
with each step up the
hierarchy (most
exclusive to most
inclusive)
Reductionism
Reducing complex
systems into simpler
parts make them more
manageable
 Limited because life’s
properties emerge with
increasing complexity
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LIVING THINGS MUST ACQUIRE ENERGY AND UNDERGO METABOLISM
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Organisms interact with
living and non-living
components
2 major processes
Recycling chemical
elements
 Flow of energy
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Some energy is converted
to heat
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Chemical within
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Light to chemical to KE to
thermal energy
Energy through
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Light in & heat out
THE CELL: FORM FITS FUNCTION
Prokaryotic Cell
Single cells
No nucleus or organelles
Smaller, less complex
Eukaryotic Cell
Single- or multi-celled
Nucleus and other organelles
Larger, more complex
CELLULAR INSTRUCTIONS
All cells have DNA (deoxyribonucleic acid)
 Direct the development of organisms through protein
production
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Inherited by offspring from parents through reproduction
 All of the genetic information inherited constitutes an
organism’s genome
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Chemical arrangement of determines function
Similar to arrangement of the alphabet into words
 Contributes to the diversity of life
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All life forms basically use the same code
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Can artificially create instructions when necessary
FEEDBACK MECHANISMS
End product speeds up process
Blood vessel damage causes platelets to
aggregate = signal more platelets
Most common
Excess end product halts process
Sugar breakdown to ATP; sufficient levels
= stop sugar breakdown
ORGANIZING AND CLASSIFYING LIFE
Different
Killer
Penguins
Crawl
OverFrozen
Glacial
Shores
Subheadings exist for all taxons
DOMAINS
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Bacteria
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Prokaryotes
Most diverse and wide
spread
Most are singled-celled
Archaea
Prokaryotes
 Live in extreme
environments
(extremophiles)
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Eukarya
Eukaryotes
 Have a nucleus and
organelles
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INTRODUCTION TO EVOLUTION
November 1859 Charles Darwin published On the
Origin of the Species by Means of Natural Selection
 Main points
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Evidence for evolution
Descent with modification
 All living organisms evolved from common ancestry
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Natural Selection was the mechanism for evolution
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Pieced together existing information
 Individual variation and overproduction of offspring
 Unequal reproductive success and accumulation of favorable
traits
THE PEPPERED MOTH STORY
http://www.expelledexposed.com/images/kettlewell.jpg
Prior to England’s
Industrial
Revolution, vast
numbers of these
moths existed. Light
in color to blend
with lichen on trees
Afterwards the
lichen began to die
and the trees
became covered in
soot.
Light colored
individuals began to
die off.
Increase in numbers
of darker colored
moths appeared.
Lighter versions
returning with
improved
environmental
standards
Biston betularia betularia morpha typica
Biston betularia betularia morpha carbonaria,
http://en.wikipedia.org/wiki/Peppered_moth
ANTIBIOTIC RESISTANCE
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Antibiotics are used to kill bacteria
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Mutations for antibiotic resistance exist or arise
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Antibiotic-resistant bacteria survive and reproduce
better than nonresistant
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Over time, proportion of antibiotic-resistant bacteria
increases
THE SCIENCE OF BIOLOGY
Science stems from natural curiosity about the world
around us
 Limited by what we can observe and measure
 Blends two forms of inquiry
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Discovery science
Verifiable observations and measurements
 General principles from a large number of specific observations
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Hypothesis based science
Seeking natural causes and explanations for discovery
observations
 Proposing and testing a hypothesis
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SCIENTIFIC METHOD
LIMITS TO THE SCIENTIFIC METHOD
 Can
never concretely prove something (No
absolute truths)
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Hypothesis
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Theory
Law
address supernatural phenomenas
 Limited by our current knowledge and
understanding
 Can’t answer moral or ethical questions
 Limited by our fallibility