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1.1 The Study of Life
Incredible diversity on earth
Bottoms of oceans
Ice shelves
Tropical rain forests
Deserts
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Diversity
Small like bacteria
Huge like blue
whale!
Single celled
Multi-celled
Heterotrophic
Autotrophic
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Biosphere
All living organisms and all the places they
are found on earth
Land environments:
Deserts
Grasslands
Forests
Water environments:
Fresh
Salt
Atmosphere
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Biosphere
Includes even strange
places!!!
Ex:
Inside of your nose
Fungi and bacteria love to
live here!
Between your toes
On your cell phone key
pads . . .
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Biodiversity
The variety of life across a biosphere
Generally:
Increases as latitude decreases (closer to equator)
Warmer temperatures
Less variation in temperatures
Organisms grow larger – More food
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Species
Several definitions . . .
:: A particular type of living thing that can reproduce by interbreeding among themselves
~ 2 million identified
> ½ are insects
Millions to be discovered!
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Every year . . .
~10,000 new species discovered
~ 50,000 species become extinct
Sometimes, the “extinct” species is discovered again:
Ivory-billed woodpecker
– “extinct” in 1944
– Discovered again in Arkansas in 2004
International video of biodiversity 8:27
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Biology
Study of all life forms (organisms)
Organism – any individual living thing
Life is not simple to define
Ex: viruses show some characteristics
of life but not all . . .
Classify as alive or dead?
Still controversy
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Cell
Basic unit of life All organisms = 1 or more
Unicellular (one celled) = most common!
Multicellular = cells with specialized functions
Ex: Muscle cells contract
Nerve cells send impulses
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Energy
Ability to cause change or do work
Chemical energy – used by all living things
Autotrophs – make own energy
Heterotrophs – eat organisms to obtain energy
Metabolism – sum of all chemical
processes that build up or break down
materials
Must have energy!
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Response to Environment
All organisms react to stimuli
Light, touch, sound
Survival tactic
Ex: Eyes when exposed to bright light
Plant grows toward light
Fly scoots away before capture
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Reproduction and Development
Organisms must be able
to make more of their
kind
DNA is passed on
Deoxyribonucleic acid
Genetic material
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Reproduction and Development
Unicellular organisms
Cell divides into two
Exact same DNA
Multicellular
organisms
Often DNA comes
from two parents
½ from each
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What characteristics are shared by
ALL living things???
1) one or more cells
2) need energy
3) respond to environment
4) ability to reproduce
The Biology Song.mp4
3 min
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1.2 Unifying Themes
Theme – a concept that comes up over and over again
Connect different areas of biology
Topics may SEEM unrelated
But there is always a common thread
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All levels have systems w related
parts
System organized group of
related parts that interact to form
a whole
Must be arranged correctly to work
Characteristics of organism
determined
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Systems
Exist at all levels:
Molecule Ex: chemical
Cell heart cell
Tissue cardiac muscle
Organ heart
Organ systems cardiovascular system
Organism YOU!
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Ecosystem
Different species
interact w each
other and physical
environment
Can be large or
small area
Ex:
Coral reef
Rotting log
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Structure and Function
Shape directly relates to
what it does
Ex:
Teeth = sharp = chewing
Heart = muscular =
constant work
Hands = mobile = grasping
Form fits function!
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Homeostasis
Maintaining constant internal
conditions despite what is
happening outside
Temperature
Blood sugar
Acidity (Ph)
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Homeostasis
Can = loss of life if not
maintained
Cells function best in limited
conditions
Ex:
Maintaining body temperature
What happens when you get cold?
– Hot?
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Evolution
Change of living things over
time
Theory of Evolution
idea that complicated species
evolved from less
complicated species
Not proven
Not agreed upon by all
scientists
Charles Darwin
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Natural Selection
A trait may allow some
individuals to survive
more easily
Survivors reproduce
more
Adaptation - A trait
that is passed on to
offspring because it
gives an advantage
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Adaptation
Different populations
of same species
might have different
adaptations in
different
environments
Eventually may not
be able to interbreed
Leads to new species
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Adaptation
Occur over many generations
Caused by environmental pressures
Not due to choices made by organisms
Long term response to environment
Does not necessarily lead to higher complexity
No special endpoint
Continual
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Unity and Diversity
Similarities of life
Diverse organisms, but
common characteristics
What is responsible for such a
complex network of life?
Science gives us insight and
continually raises questions
Evolution. . . 1:46 clip
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1.3 Scientific Process
Biology requires inquiry
Based on curiosity and skepticism
Skepticism – use of critical and
logical thinking to evaluate results and
conclusion
Requires evidence
Exchange of data
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Data
Observations can be recorded as such
Two types of data
Qualitative – sights, sounds, smells
Report WHAT happened but not HOW
Quantitative – can be measured or counted
Mass, volume, temp, etc
Can be expressed as a number
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Hypothesis
Proposed answer for scientific
question
Must be specific and testable
Use scientific literature, observations,
and data
Poison dart frog clip 8:00
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Testing Hypotheses
One test is not usually enough
Biological systems are
variable
Testing many times takes these
variances into account
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Hypotheses Outcomes
2 Possible:
Nonsignificant – data show no effect
OR could have happened by chance
Rejected
Still useful
– Develop new hypotheses!
Statistically Significant – effect not
likely due to chance
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Evaluation of methods/results
Peer review – other scientists go over
How was:
Experiment done?
Data analyzed?
Did conclusion support data?
Bias?
Results may then be accepted
Lead to new experiments
Continuous cycle
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Experiments
Used to test hypotheses
Find out how something
happens
Use variables to find out
cause-and-effect
relationships
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Variables
Independent – manipulated by scientist
Usually only one in experiment
Dependent observed and measured
The experimental data that we record
Changes in dependent variables “depend upon” the manipulation of independent variables
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Constants
Conditions that do not
change during
experiment
Control Group –
conditions in this group
remain constant
Compare other groups to
this group
“baseline” group
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Theory
Proposed explanation for wide range
of observations and experimental
results
Supported by evidence
NOT a speculation
May become widely accepted
NOT proven
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Theory
Not easily accepted
Never “proved”
Always subject to change or
replacement
Ex: Germ theory
Used to think illness was caused by
imbalance in humors
Then realized there were microorganisms
Now studying prions and viruses
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Law
Truth that is valid everywhere in the
universe
Ex: law of conservation of energy
Energy may change form, but cannot be
created nor destroyed
Describes nature of energy, but does not
give explanations
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1.4 Biologists’ Tools & Tech
Cells not
discovered until
late 1600s
Microscope
invented
Allows study of
enlarged images
Changed
biological studies
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Microscopes
Light microscopes (LM)
magnify up to 1500x - 2000x
See living or preserved specimen
Samples often stained
See pg. 21 images
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Microscopes
Electron microscopes
1950s
Up to 500,000x magnification
Study individual proteins
Cannot study living specimens In a vacuum
Black and white images seen on computer
Artificial color added for our viewing pleasure
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Electron Microscopes
Scanning Electron Microscope (SEM)
Uses beam of e- to scan surface of specimen
Usually surface coated w thin layer of metal
– Deflects e-
Computer forms 3D image of deflected e-
Used in forensic science – Fingerprints, gunshot residue,
forged money
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Electron Microscopes
Transmission Electron
Microscope (TEM)
Transmits e- thru thin
slice of specimen
2D image
Mitochondria section image
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Medical Imaging
X-rays
Pass thru soft tissue (skin, muscle)
Absorbed by hard tissue (bone, teeth)
Great for looking at skeleton
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Medical Imaging
MRIs (magnetic resonance imaging)
Magnetic field produces cross-sections
Used to view soft tissues
fMRI – functional MRI
Used to show brain activity
MRI of knee joint
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Computers
Used to model complex
systems
Ex: atoms in a cell
How water flows thru cell
membrane
Ex: how diseases spread
How far?
How fast?
Who will get it?
When?
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Molecular Genetics
Study and manipulation of
DNA on a molecular level
Study:
Evolution
Ecology
Biochemistry
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Molecular Genetics
40 years ago:
Did not know how genetic code
worked
Now:
Manipulate genes
Implant from one species to
another
Replace faulty genes
Gene – segment of DNA that
codes for a trait
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Genomics
Study and comparison of genomes
both within and across species
Combines molecular genetics with
computers
All info is managed by computers
Entire genomes known
Genome – entire DNA sequence of an
organism
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Data Mining
Searching computer data
bases
Find DNA patterns,
similarities, and differences
This is all new within the last
20 years
What will your kids be
learning about in school????
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1.5 Biology and Your Future
Many of your decisions involve
biology
Personal and societal
Medical research
Pollution
Health
Endangered species
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Bio and Your Health
Food and water
contamination
Food poisoning
Vitamin and mineral
deficiencies
Food allergies
Can be life threatening
Ex: peanuts, shellfish
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Bio and Your Health
How much to eat?
What to eat?
~60% of adults in the U.S. are
overweight or obese
Increased risk:
Diabetes
Stroke
Heart disease
Breast cancer
Colon cancer
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Bio and Lifestyle Choices
Sunscreen
Exercise
Tobacco
Illegal drugs
Alcohol
How do these impact my longevity?
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Funky Frogs
1995
Students discovered frogs w
abnormalities in MN
What caused the problem?
Parasitic infection
Is it linked to chemical
produced by factories too?
What action does one take?
Deformed Frogs 4:18
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Understanding Biology Helps!
Ask questions
Make informed decision
Take proper action
Pollution
Biodiversity
Habitat preservation
Natural resource use
You play an important role
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Biotechnology
The use and application of living things and biological processes
Some used for centuries
Ex: making bread and cheese
Some recent
DNA testing
Medicine
Agriculture
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Biotech and Organisms
Domestic animals and
plants
Selective breeding has been
occurring for centuries
Choose organisms to breed
that have desired traits
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Transgenic Organisms
Have genes from more than one
species OR have altered copies
of their own genes
Ex:
Bacteria make insulin
Sheep and cows make antibodies
and proteins
Genetically modified foods
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GM Food
Benefits:
More
Extra nutrition
Resistant to pesticides, drought, etc
Risks:
Gene spread to wild plants
Healthy?
Effects not fully known
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Human Genetic Screening
Analysis of genes to ID variations
Benefits:
Determine disease risk in offspring
Treat illness before it occurs
Risks:
Access
Insurability
Choose child’s characteristics