Unit 1The Science of
AP Biology
Mrs. Stahl
Introduction to the Four Big Ideas
Big Idea 1- Evolution
• Darwin (1809-1882):
– English Naturalist
– Studied and observed life for 30 years and then
published “Origin of Species.”
– His story began in 1831 (22 years old) when he took a
five year trip on the HMS Beagle.
– He observed that the characteristics of similar species
varied somewhat from place to place-> lineages change
gradually as species migrate from one area to another.
Galapagos Islands
• Located off the coast of Ecuador.
• Main discovery = finches.
– Discovered 14 species that were related, but they all had
different beaks.
– He stated that they derived from a common ancestor
from the mainland.
– Discovered that they ate different foods (island specific)
which changed their beak shape. They had to adapt /
change their beaks shape in order to survive and forage
(hunt for food / eat).
http://bio1100.nicerweb.com/Locked/media/c
h14/galapagos.html
Descent with Modification
• The finches genes changed over time in order
to adapt to the food source. If they didn’t
adapt and change, they would die off.
Other Observations
• Plants and animals were similar on the little
volcanic islands just like they were on the
mainland.
• Natural Selection = Main mechanism. The
strong will adapt and survive. Those that don’t
will die.
Thomas Malthus- Influenced Darwin
• Population of plants and animals tend to
increase geometrically (increases by a
constant factor) while humans increase their
food supply arithmetically (increases by a
constant difference) = limit on human survival.
– What happens when the food runs out?
Human growth =
geometric
Human food production =
arithmetic
10
Intrigued Darwin
• Took the idea and his observations and saw that
every organism can reproduce more offspring than
can survive, but only a limited number actually do
survive and produce viable offspring.
• Those that have physical or behavioral attributes
have the advantage = NATURAL SELECTION!
Evidence of Natural Selection
• 1. Fossil Record-> linked intermediate groups
• 2. The age of the Earth, 4.5 bya
• 3. Heredity- genes were passed on from generation
to generation. The strong favorable ones.
• 4. Comparative Anatomy- vertebrate bones are
similar= common ancestor.
– Homologous- same basic bones but they differ in
structure and function.
– Analogous- structures that are similar in function but
differ in origin.
Homologous
Structures
Analogous
Structures
http://bio3vo.wordpress.com/evolution/
More Evidence
• 5. Molecularlooking at
patterns based on
the sequencing of
genes (genome).
– Phylogenetic
trees- family tree
of genetics
Big Idea 2- Energy and Molecular
Building Blocks
• 1. Free Energy:
– Cellular Respiration and Photosynthesis. How this cycle
is continual and vital for the movement of energy from
food and sunlight to ATP (Adenosine Triphosphate).
– Without these processes there would be no life on
Earth.
– Molecules and cells are used and recycled, and new cells
grow and develop.
• 2. Compartmentalization–Membranes are the first line of defense.
–Create boundaries for protection, allow
crucial processes such as photosynthesis
and cellular respiration to occur.
–Allows enzymes to function properly.
Enzymes speed up rates of reactions so
that processes can occur at a faster rate
(maintain homeostasis).
• 3. Feedback Mechanisms:
– Keep things normal or balanced
– Positive Feedback loops are going to increase a
needed reaction such as hibernation, nocturnal
adaptations, and phototropism
– Negative feedback loops focus on trying to keep
internal conditions stable.
• Ex- Shivering increases body temperature
• Ex- Insulin is released when glucose levels are low
• Ex- Sweating occurs to lower body temperature
• 4. Maintaining Homeostasis:
–Constant internal balance
–Adapt, migrate, or die
• 5. Timing, Coordination, and Regulation
– Development from an egg
– Has to have perfect timing and coordination of sex cells
– Some result in apoptosis= cell death
– Genetic Mutations
– Plants telling the difference between dark and light
– Organisms communicating with one another for
migratory purposes as well as reproduction.
Big Idea 3- Information, Storage,
Transmission, and Response
• DNA is the blueprint for life
• DNA= Deoxyribonucleic Acid
• Sequences of nucleotides make up our genes and
millions of nucleotides make our chromosomes.
• Cell Cycle allows growth and repair of DNA
• Mitosis and Meiosis (Mitosis = body cells, Meiosis =
gametes or sex cells)
• Genetic Variation- increases diversity in a population.
• Cell to cell communication and response
• Cells are like little factories that process tons of
information
Big Idea 4- Interdependent Relationships
• Interactions among populations: Symbiosis,
prey/predator relationships, cell to cell interaction
• Diversity- the more diversity the better
• Flow of energy through food webs and food chains
• How your cells, tissues, organs, and organ systems
work together to function properly.
– EX- Your heart would not be useful if it didn’t have blood
and blood vessels.
– EX- You wouldn’t be able to survive if plants weren’t
around.
Characteristics of Living Things
• All living things must be able to:
– 1. Reproduce
– 2. Made up of cells
– 3. Respond to a stimulus
– 4. Grow and develop
– 5. Evolve and change
– 6. Metabolize- need and use chemical energy
– 7. Maintain Homeostasis
– 8. Made up of DNA
Made up of Cells
• Smallest and basic unit of
life.
• Each level builds on the level
below it.
• Ex- within a cell
macromolecules are
assembled into ribosome's,
chromosomes, and
membranes and they are
then built upon to form
organelles such as the
mitochondria.
Continues on to populations and
species.
DNA- Deoxyribonucleic acid
• Stores genetic information
• Made up of nucleotides (4 nitrogenous base
pairs-AGCT), sugars, and phosphates.
• Adenine (A) pairs up with Thymine (T)
• Guanine (G) pairs up with Cytosine (C)
• The sequence of the bases is what codes for
the order of amino acids in the protein
sequence (amino acids).
Reproduction
• Life has to come from prior life / DNA has to be
passed on.
• Living forms reproduce to generate others like
themselves: binary fission, asexual reproduction,
or sexual reproduction.
• Genes replicate to form new genes
• Cells divide to produce new cells- binary fission
• Populations split up and new species are
produced= speciation.
Metabolism
• Have to acquire nutrients from their environment in
order to maintain proper energy levels.
• Nutrients-> chemical energy for the body to use in
the form of ATP.
• Chemical processes include digestion, respiration,
and synthesis of molecules.
• Interaction between catabolic (destructive) and
anabolic (constructive)
• Cellular Respiration-> mitochondria
• Cellular and nuclear membranes regulate
metabolism by controlling the movement of
molecules in and out of the cell.
Growth and Development
• All organisms have a life cycle that they go
through from origin (when the sperm fertilizes
the egg = fertilization) to adulthood.
• Changes in size, shape, and differentiation in
structures.
• Unicellular are more simple than Multicellular.
• Metamorphosis- many organisms have similar
early stages of development and are hard to
tell apart and then they change.
Stimulus
• How do they interact / respond with their
environment?
• Often referred to as ecology, focusing on
geographic distribution and population
abundance.
• They respond by adapting their metabolism and
physiology so that they can survive in the
environment in which they live.
Evolution
• Change over time.
• Ex- Darwin’s finches- he found 14 different
species of finches that derived from one. They
had different beaks to adapt to the type of
seed they fed upon.
Homeostasis
Maintaining constant internal conditions in an
organism. Body temp. is 37 C or 98.6 F
Important because cells function best within a
certain range of conditions. Temperature, blood
sugar, acidity, must be controlled or it can be fatal.
Maintained-> negative feedback loop= change in a
system causes a response that tends to return that
system back to its original state.
Ex- The control of blood sugar (glucose) by
insulin is another good example of a negative
feedback mechanism. When blood sugar rises,
receptors in the body sense a change . In turn,
the control center (pancreas) secretes insulin
into the blood effectively lowering blood sugar
levels. Once blood sugar levels reach
homeostasis, the pancreas stops releasing
insulin.
http://anatomyandphysiologyi.com/homeosta
sis-positivenegative-feedback-mechanisms/
Diversity of Life
• Arises by evolutionary change leading to
the present biodiversity we see.
• Divided into three Domains:
– 1. Bacteria- single celled prokaryotes (no
nucleus)
– 2. Archaea- single celled prokaryotes (no
nucleus)
– 3. Eukarya- Plants and Animals, complex
organelles and multicellular.
Taxonomy
• Classifying
Organisms
http://www.charlesayoub.com/lifestyle/index.php/more/1/1018
Domain Eukarya
• 4 Kingdoms
– 1. Kingdom Protista: unicellular eukaryotes,
multicellular algae (dinoflagellates, diatoms, etc)
– 2. Kingdom Plantae: have cells walls, cellulose, and
obtain energy through photosynthesis.
– 3. Kingdom Fungi: Cell walls are made of chitin,
obtain energy by secreting enzymes and absorb the
products they release.
– 4. Kingdom Animalia- no cell walls, obtain energy by
ingesting other organisms.
Living Systems Show Hierarchical
Organization
• Life is highly organized
• Begins with atoms and ends with the
biosphere.
• Cellular Level: Atoms-> Molecule->
Macromolecule-> Organelle-> Cell
• Organismal Level: Tissue-> Organ-> Organ
System-> Organism
• Populational Level: Population-> Species->
Community-> Ecosystem-> Biosphere
Cellular Level and Organismal Level
http://sphweb.bumc.bu.edu/otlt/MPH-
Populational Level
http://eweb.furman.edu/~wworthen/bio111/1
02science1lec.htm
Science Practices
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Science Practice 1
The student can use representations and models to communicate scientific phenomena and
solve scientific problems.
Science Practice 2
The student can use mathematics appropriately.
Science Practice 3
The student can engage in scientific questioning to extend thinking or to guide investigations
within the context of the AP course.
Science Practice 4
The student can plan and implement data collection strategies in relation to a particular
scientific question. (Note: Data can be collected from many different sources, e.g.,
investigations, scientific observations, the findings of others, historic reconstruction and/or
archived data.)
Science Practice 5
The student can perform data analysis and evaluation of evidence.
Science Practice 6
The student can work with scientific explanations and theories.
Science Practice 7
The student is able to connect and relate knowledge across various scales, concepts and
representations in and across domains.
Scientific Theory and Reasoning
• Theory is used in two ways:
–1. Proposed explanation for some natural
phenomenon, often based on some general
principle.
• Ex- Newton’s theory of gravity= brought
together concepts that were previously
thought to be unrelated.
• 2. Theory- body of interconnected concepts,
supported by scientific reasoning and experimental
evidence.
– Ex-Quantum theory- brings together a set of ideas about
the nature of the universe, explains experimental facts,
and serves as a guide to further questions and
experiments.
– EX- Theory of Evolution
The Scientific Method
• A series of steps used to set up an
experiment in order to test a
hypothesis or solve a problem.
Steps
1.
2.
3.
4.
5.
6.
7.
Make an observation
Ask a question / Research
Form a hypothesis
Experimentation
Collect data / Results
Analyze and Conclude
Repeat
Observation
Using your senses to study the
natural world.
Can also use tools such as
previous biological research and
computers.
Inference= logical interpretation
based on prior knowledge.
Ask a Question
Do other sharks jump out of the water or just
white sharks?
Hypothesis
Not an EDUCATED GUESS- in science
we don’t like to say that we are
“guessing.”
Prediction based on prior knowledge.
Typically use the words If and Then!
Inductive vs. Deductive
• Logic flows in the
• General principles to
opposite direction, from
predict specific results.
specific to the general.
• To the point.
• Ex- If poodles have hair, • Ex- If all mammals have
and terriers have hair,
hair, and you find an
and every dog that you
animal that does not
observe has hair, then
have hair, then you may
you may conclude that
conclude that this
all dogs have hair.
animal is not a
mammal.
Example of a Hypothesis
• If five plants are placed in the sunlight
and five plants are placed in the darkness
for 10 hours per day for 10 days, then the
plant in the sunlight will grow taller.
Experiment
Try to find the cause and
effect relationship.
Independent Variable
• What you, the experimenter changes or
manipulates.
• Example- number of days in the sunlight,
location of the plants.
Dependent Variable
• The variable that changes because of the
IV (results / data).
• Example- height of the plant
Control Variable
• Variables that is the “norm”
• Example- plant placed in normal
conditions.
Data
Qualitative= descriptions using
your senses
Quantitative= Numbers
Results
• Statistical analysis
• Use data tables and graphs to
represent data collected.
Analysis and Conclusion
• Explain your results in detail.
• Describing your graphs and data in
words.
What happens if your hypothesis is
wrong?
Try again, revamp your procedure /
experiment.
Theory
Law
• A well supported
explanation.
• Why something happens
• Explanation of Nature
• Based on Evidence
• Ex- Theory of Evolution
•
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What will happen
Predictable outcomes
Based on evidence
Example- Newton’s Laws of
Motion
Not in your notes
• Throughout the year we will be doing a lot of
graphing, reading data tables, etc. This is a
review of the types of results you will be
expected to do!
Graphing and Measurements
Y-axis /
DV
X- axis / IV
We use charts and graphs to:
• Analyze the results and to provide visual
summaries
Data Tables
• Contains the numerical results of an
experiment. Compiled before you make a
chart or graph.
Color of M&M in a bag
Frequency
Red
5
Green
2
Blue
4
Yellow
1
Brown
5
Line Graphs
• Shows a relationship between two variables.
Bar Graphs
• Compares quantitative / qualitative data.
Histograms
• Show the frequency distribution of the data.
• The bars touch!
• Ex- using the numbers make a data table and
histogram in your notes.
– 7, 12, 12, 18, 22, 24, 26, 27, 28, 29, 31, 36, 36, 39,
43, 47
Histogram Data Table
Data Range
0-10
11-20
21-30
31-40
41-50
Frequency
1
3
6
4
2
Stem and Leaf Plot
• Another way to present a frequency
distribution.
• Represents actual data point
• Tens= “stem”
• Ones= “leaves”
Stem
Leaf
0
7
1
228
2
246789
3
1669
4
37
Circle Graph
• Shows data as proportions of a whole
• “pie chart”- percentages
The Metric System- see attached note
sheets
• IS- International System of Measurements
– Used worldwide
– Based on the metric system
– Common units:
•
•
•
•
Length- Meters (m)
Volume- Liter (L)
Mass- Kilograms (kg)
Temperature- Kelvin (K)
Microscopes!!!!!!!!!!
Light or Compound Microscopes
• What we use in the classroom- basic
• Several lenses to increase
magnification
• Uses glass lenses to focus on a
specimen.
• Can be used on living or preserved
specimens
• Can magnify objects up to 1500
times their actual size.
• Specimens are often stained with
chemicals so that we can see them.
stoma
Dissecting Microscope
• Stereoscope
• Three dimensional image / view of the
specimen
• Essentially two compound microscopes that
are focused on the same thing.
• Low magnification so its hard to see individual
cells- used for larger cells.
Scanning Electron Microscope
• Narrow beams of
electrons that scan the
surface of the specimen
stoma
Transmission Electron Microscope
• Internal and cannot be used to
view living things.
• Passes beams of electrons
through the specimen and
projects it onto a computerized
screen where color is added.
• Produces the best image
because it magnifies the object
so much.
stoma
Parts of a Microscope
• Nosepiece- holds the objective lenses above the
stage and rotates so that all the lenses can be
used.
• Low Power Objective- magnifies an image 10X
• Stage clip- holds the slide in place
• Stage- supports the object being looked at.
• Diaphragm- adjusts the amount of light passing
through the slide and into the lens.
• Light source- lights up the specimen
• Eyepiece- contains a lens that magnifies the object
10X. You look through this to view the specimen.
• Body- separates the lens in the eyepiece from the
other lens.
• Arm- supports the body and this is where you hold it
while supporting the base.
• Scanning Objective- smallest lens and magnifies 4X
• High Power Objective- largest lens and magnifies 40X
• Fine Adjustment- dial used to focus in on the object
when it’s on high power.
• Coarse Adjustment- used to focus the image when it’s
on scanning or low power.
• Base- supports the scope.
Magnification- draw into notes
3 types- scanning, low, and high
Ocular lens is
always 10X
Magnification
Magnification
Total
Magnification
High
Power
40x
10x
400x
Low
Power
10x
10x
100x
Scanning
4x
10x
40x
Magnification- draw into notes
3 types- scanning, low, and high
Ocular lens is
always 10X
Magnification
Magnification
Total
Magnification
High
Power
40x
10x
400x
Low
Power
10x
10x
100x
Scanning
4x
10x
40x
Websites Used
• http://uhsbiologyproject.blogspot.com/p/nat
ural-selection.html
• http://www.saawinternational.org/geeseandd
ucks.htm
• http://advancesinap.collegeboard.org/mathand-science/science-practices