1.3: studying life vocabulary: –biology –dna –stimulus –sexual reproduction –asexual...
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1.3: Studying LIFE
• VOCABULARY:– Biology– DNA– Stimulus – Sexual reproduction– Asexual reproduction– Metabolism– Homeostasis– Biosphere– Evolve
What are some characteristics of living things? What does it mean to be “ALIVE”?
1) Living things are ORGANIZED.
1) Living things are ORGANIZED.
• Made up of cells
–UNICELLULAR: one celled
–MULTICELLULAR: many celled
• Growth: increase in size & formation of new structures (could be at the cellular level)
• Development: cells increase in number and become different (differentiate)
• Heat
• Light
• Pressure
• Sound
• Gravity
Examples:
• A plant seed only germinates when there is sufficient water and temperature.
• Plant roots grow down.
• Plant leaves grow towards sunlight.
• HOMEOSTASIS: process by which organisms keep their internal conditions relatively stable–Example: How do humans maintain the
same body temperature?• too hot… we sweat• too cold… we shiver
7) Living things require ENERGY.
• All living things use energy: make their own energy or consume energy– PHOTOSYNTHESIS: using light energy to make
“food” energy– METABOLISM: combination of chemical
reactions through which an organism builds up or breaks down materials
Photosynthesis
Uses Metabolism
8) ADAPTATION & EVOLUTION
● ADAPTATION: any structure, behavior, or internal process that enables an organism to respond to stimuli and to better survive in a particular environment
8) ADAPTATION & EVOLUTION
● EVOLUTION: change over time–A group of organisms can change over
time–Even though an individual develops,
their inherited traits do not change
leg bone in a whale
Branches of Biology
• Diversity of life is so great,
biology is separated into branches– ZOOLOGY: study animals
– MICROBIOLOGY: study bacteria
– BOTANY: study plants
– ETHOLOGY: study animal behavior
– PALEONTOLOGY: study life from the past
Biosphere > Ecosystem > Community > Population >
Organism > Organ Systems > Organs > Group of Cells (Tissues)
> Cells > Molecules > Atoms > Protons, Neutrons, Electrons
How do we study living organisms?
• Key Concepts:– What measurement
system do most scientists use?
– How are light microscopes and electron microscopes similar? How are they different?
• Vocabulary:– Metric system– Microscope– Compound light
microscope– Electron microscope– Cell culture– Cell fractionation
Analyzing Biological Data The simple way to record data
● Make a table…
● Then make a graph– Graphs make patterns
easier to recognize
and understand
GRAPH = visual representation of data
1) DESCRIPTIVE title
2) x and y axis labeled
3) units for both the x and y axis
4) scale is evenly and correctly spaced for data
5) legend / key when appropriate
Organizing DataData is organized and presented in tables, charts, and graphs.
LINE GRAPH: best for displaying data that CHANGE.– Independent Variable: x-axis– Dependent Variable: y-axis
Temperature Increase of a Beaker of Water
250
300
350
400
450
0 50 100 150 200 250 300 350 400
Time (sec)
Tem
pera
ture
(K)
BAR GRAPH: useful when you want to compare data for several individual items
Leading Causes of Death in 2000
300
233
107 9857
0
50
100
150
200
250
300
350
HeartDisease
Cancer Diabetes Accidents HomicideNu
mb
er
of
De
ath
's p
er
100,
000
Pe
op
le
MICROSCOPESCOMPOUND LIGHT MICROSCOPE: most
common scope• Advantages: get higher magnification
than with a dissecting scope.• Drawbacks: the light comes from below
so sample must be very thin so you can see – Useful for viewing single cells– Usually view dead things with this
microscope.• Limit of resolution: if you magnify beyond
this point, the object will be blurry.
EYEPIECE
LOW-POWER OBJECTIVE
HIGH-POWER OBJECTIVE
STAGESTAGECLIPS
STAGECLIPSBASE
MIRRORLAMP
IRIS
DIAPHRAGMCOURSE ADJUSTMENT
FIN
E
AD
JUS
TM
EN
T
ARM
COURSE ADJUSTMENT
FINE ADJUSTMENT
ARM
DISSECTING MICROSCOPE: used to view dissection or small live (sleeping) animals such as fruit flies.
• Advantages: can view samples that are alive; large field of view
• Drawbacks: magnification is not as high as other microscopes.
SCANNING ELECTRON MICROSCOPE (SEM): used to see very small “stuff”
• Advantages: can study very small objects such as viruses and individual molecules; limit of resolution is 1000x that of a light microscope.
• Drawbacks: done in a vacuum, so object must be dead; also very expensive!
Laboratory Techniques
● Cell Culture:
-a group of cells develops from a single original cell.
● Cell fractionation & Centrifugation:
-used to separate the different parts of a cell1) Cells are blended
2) Added to a liquid and placed in a tube
3) Centrifuge at 20,000 revolutions per minute
4) Spinning separates the cell parts by density.
In comparing differences in sea level from decade to decade, a scientist
should use what type of graph?
a) Bar graph
b) Pie Chart
c) Line graph
On that graph, what would be on the x-axis? On the y-axis?
X-axis = time in decades
Y-axis = sea level in kilometers