Biology Introduction
Scientific Method
Steps of the Scientific Method
1. Observation
2. Hypothesis
3. Experimental Design/Data Collection (Testing the
Hypothesis)
4. Analysis (Explaining the Data)
Important Scientific Method Terms
-Control  Factor in an experiment that stays the same throughout the
course of the experiment. All good experiments have at least one control
-Variable  Factor in the experiment that changes. The fewer the
variables in an experiment, the better the design.
-Theory  Hypothesis that is tested repeatedly and never disproved
Scientific Law/Principle  Scientific truths that are valid everywhere in
the universe
Fact  Truth known by actual experience or evidence
Belief  Opinion or conviction that something is true
Properties Of Life
1. Made of cells
2. Reproduction
3. Universal genetic code
4. Growth and development
Growth- Increase in Amount of material in an organism
Development- Series of changes an organism undergoes in
5. Obtain & use energy (from food or sun)
6. Respond to their environment
Stimulus: anything in an organism’s environment that
causes it to react
7. Homeostasis: Organisms maintain constant internal
conditions regardless of external changes
Examples?
8. Evolve: Species change over time
Taxonomy and Classification
Taxonomy- Science of identifying,
classifying, and naming organisms
Taxa- Categories into which biologists
classify organisms
Taxa
•Kingdom, Phylum, Class, Order, Family,
Genus, Species
•King Phillip Came Over For Good Soup
Classification
Kingdoms of Life
• Traditionally, 5 kingdom system used to
classify life…
1.Protista
2. Fungi
3. Plantae
4. Animalia
5. Monera- which includes
Archae (Kingdom: Archaebacteria)
Bacteria (Kingdom: Eubacteria)
Biochemistry
Matter & Elements
•All matter made of elements (atoms)
•All atoms have structure
•Protons/electrons/neutrons? Charge? Mass?
•# of protons in nucleus determines atom’s identity
•Ions atoms that gain or lose electrons
Hemoglobin
Atom
Atomic Structure
Protons carry a +1 charge, mass of 1 AMU
Neutrons carry a 0 charge; mass of 1AMU
Electrons  carry a –1charge; mass of 0 AMU
Nucleus  consists of protons and neutrons; central part
of the atom
Electrons  move around the nucleus
Why Atoms Form Bonds
•2 or more elements = compound
•1st 20 elements have up to 3 energy levels/ 2 electrons on
1st level, up to 8 on 2nd level, and 8 on the 3rd level
•Most elements want to have 8 electrons in outer shell
•Atoms will share or steal to get 8 electrons in outer shell
•Sharing electrons covalent bonds
•Stealing electrons ionic bonds
Covalent Bond In Action
Ionic Bond In Action
Acids and Bases
Pure water has equal amounts of H+ and OHIf equal number of H+ and OH-, solution is neutral
pH Scale
Scale measures amount of H+ ions
in solutions
pH = 7-neutral
pH< 7 –acidic
pH > 7--basic
Polarity of Water
Structure of water is VERY unique
H2O
•Oxygen has 8 protons & 8 electrons
•Opposites attract, and electrons are pulled in close to the
nucleus
•Hydrogen has 1 proton & 1 electrons
•Not held together very closely
Polarity of Water
Ice floats:
•When water freezes, hydrogen bonds lock
water molecules into a structure that has empty
spaces, making it less dense than liquid water
Water absorbs and retains heat
Because of hydrogen bonds, water can absorb large
amounts of energy
Absorbs lot of heat before it boils
Helps keep cells at an even temperature despite
changes in the environment – homeostasis again!!
Allows large bodies of water to maintain a relatively
constant temperature.
Organic Molecules
Carbohydrates
•provide energy to cells
•help build cell structures
•monosaccharides= 1 sugar unit
•disaacharides = 2 connected sugar units
•polysaccharides = more than 2 connected sugar units
Glucose- The Ultimate Carbohydrate
Lipids
Fats (triglycerides)
Used for energy
Long chain molecules
Triglyceride = 3 FA’s + glycerol
Saturated= not easily broken down (all single bonds)
Unsaturated= easily broken down (double bonds)
The Phospholipid Bilayer
Proteins
THE structural material of the body!
1. Hormones
2. Receptors
3. Enzymes
Made from Amino Acids (connected via peptide bonds)
Collagen
Hemoglobin
Nucleic Acids
•Make our genes
•Instruct body which proteins to make
•Made from nucleotides
•DNA + RNA
Ecology Review
Living things do not live in vacuums, their daily
lives are based on interactions with both
living and nonliving things.
What is an ecosystem?
Groups of organisms and their physical
environment
What is the Biosphere?
All forms of life on Earth are connected in a
biosphere
34-27
Ecology Terms
Organism living thing
Population groups of living things
Communitygroup of populations
Ecosystemgroup of communities
Biome Group of ecosystems
Biosphere Group of biomes
34-28
There are two main components of an
ecosystem:
Biotic (living)
Populations of
organisms.
&
Abiotic (nonliving)
Inorganic nutrients,
physical features,
water, temperature,
and wind.
34-29
Biotic Components: A Closer Look
Autotrophs are producers that produce
food for themselves and for
consumers.
How do autotrophs make food?
Photosynthesis and chemosynthesis
Heterotrophs are consumers that take
in premade food.
34-30
Consumers Vocabulary:
Herbivores – animals that eat plants
Carnivores – animals that eat other animals
Omnivores – animals that eat plants and
animals
Decomposers - bacteria and fungi, that
break down dead organic waste.
Detritus - partially decomposed organic
matter in the soil and water; beetles,
earthworms, and termites are detritus
feeders.
34-31
Consumer Levels
Primary consumer – an organism that
gets its energy from plants (producers)
Secondary consumer – an organism that
gets its energy from primary consumers
Tertiary consumer – carnivores that eat
other carnivores; a top-level consumer,
usually the top predator in the food chain
34-32
Food chain
34-33
Forest food webs
34-34
Ecological Pyramids
Why are food chains so short?
Only about 10% of energy is useable from one
trophic level to the next
• The number organisms drastically decreases as
you go up in level of a food chain
What is an ecological pyramid?
A series of blocks representing the biomass of
particular organisms on a particular trophic level
What is biomass?
The amount of living material in the population of
an organism
34-35
Ecological pyramid
34-36
Biochemical cycles
What are biochemical cycles?
• The path by which important
nutrients/molecules travel through an
ecosystem.
4 Important Cycles:
• Water Cycle
• Carbon Cycle
• Nitrogen Cycle
• Phosphorous Cycle
34-37
The Water Cycle
Water movement:
Land  Atmosphere:
• Liquid  Gas
• Evaporation from rivers, lakes and oceans
• Transpiration from plants
Atmosphere  Land
• Gas  Liquid
• Precipitation over land and bodies of water
• Runoff forms bodies of water (lakes, rivers, oceans)
• Ground water seepage into aquifers
34-38
The water cycle
34-39
The Carbon Cycle
Carbon Movement:
Land/Water  Atmosphere
• Respiration
• Combustion
Atmosphere Land/Water
• Photosynthesis
• Dissolved CO2
** Carbon is stored as _fossil fuels__ from decaying
organisms.**
34-40
The carbon cycle
34-41
The Nitrogen Cycle
Nitrogen Movement:
1. Nitrogen Fixation  Bacteria found in legume
roots converts N2 gas into Ammonia (NH4)
2. Decomposers break down waste and organic
remains into Ammonia (NH4)
3. Nitrification  bacteria convert ammonia into
Nitrite (NO2) and Nitrate (NO3) to be used by plants
4. Denitrification  Bacteria converts ammonia
back into Nitrogen gas (N2)
34-42
The nitrogen cycle
34-43
The Phosphorus Cycle
The phosphorus cycle is a sedimentary cycle.
Only limited quantities are made available to
plants by the weathering of sedimentary
rocks; phosphorus is a limiting inorganic
nutrient.
The biotic community recycles phosphorus
back to the producers, temporarily
incorporating it into ATP, nucleotides, teeth,
bone and shells, and then returning it to the
ecosystem via decomposition.
34-44
The phosphorus cycle
34-45
Changes to Ecosystems
• Air Pollution  Burning of fossil fuels
releases CO2, SO2, and NO2,NO3 into
atmosphere. Results in climate change,
acid rain, damage to ozone layer
34-46
Habitat Destruction
• Over past 50 years, 50% of tropical forests
have been cleared for timber or farmland
(deforestation)
• Loss of habitat often means extinction for
organisms within that habitat
34-47
Invasive Species
• Introduction of species to new habitats,
usually by humans
34-48
Game Time!
A
B
C
2. Which statement is correct regarding acids
and bases?
A. Acids increase the pH and bases decrease
the pH.
B. Acids release hydrogen (H+) ions [or
hydronium (H3O+) ions] and bases release
hydroxide (OH-) ions.
C. Acids are harmful but bases are not harmful.
D. Acids combine with bases to form sugars.
3. Proteins are a major part of every living cell
and have many different functions within each
cell. Carbohydrates also perform numerous
roles in living things.
Part 1. Describe how the structures of
proteins differ from the structures of
carbohydrates.
Part II. Describe how the functions of
proteins and carbohydrates differ.
5. In an experiment, what happens to the
control group?
A. It receives no experimental treatment.
B. It receives experimental treatment
last.
C. It receives experimental treatment
first.
D. It receives more experimental
treatments than the other groups.
9. Look at the graph below. What is the
dependent variable? What is the
independent variable?
Use the table below to answer question 10.
Students’ Observations of a Pond Ecosystem
7. A group of students measured a ten-square-meter section
of a pond ecosystem and recorded observations. Which
statement is a testable hypothesis?
A. The frogs living in the pond represent a population.
B. Water is an abiotic component in the pond ecosystem.
C. If the fish are given more food, then they will be
happier.
D. If the frogs are startled, then they will jump into the
1. Isle Royale is located in Lake Superior. Isle Royal is home to
populations of wolves and moose. The interactions between the
wolves and moose, as well as the individual population sizes, have
been studies since 1958. The graph shows the populations sizes over
time for both wolves and moose. Explain 1 likely reason why the wolf
population increased between 1975 and 1980.
2. A researcher observing an ecosystem describes the amount of
sunlight, precipitation, and type of soil present. Which factors is
the researcher most likely describing?
a. biotic factors in a forest
b. biotic factors in a tundra
c. abiotic factors in a prairie
d. abiotic factors in an ocean
3. In a marine food web, there is a far greater mass of algae
than of all the killer whales. Why is this so?
a.whales are bigger than algae
b. an alga has more mass than a killer whale
c. whales don’t eat algae
d. it takes a massive amount of algae to support a food web
with a killer whale at the top.
4. In a meadow food chain, which is the correct
sequence of the path of energy flow?
a. hawk snake  mouse grass
b. mouse  grass hawk snake
c. grass mouse snake hawk
d. snake  mouse  hawk grass
5. The maximum population that the environment can support for an
indefinite period of time is called the __________________
a. biotic potential
b. environmental resistance
c. carrying capacity
d. replacement reproduction.
6. The ultimate source of energy for producers
and all consumers is
a. plants.
b. the sun.
c. algae.
d. the ocean.
7. The figure above represents a
a. trophic net.
b. food chain.
c. food net.
d. food web.
8. The algae are __________________ while the leopard seals are
___________________.
a. producers, carnivore
b. carnivore, omnivore
c. producer, omnivore
d. carnivore, producer
9. Using the following terms, trace the cycling of water between
the atmosphere and the earth: Evaporation, transpiration,
precipitation.
10. Why are producers an
essential component of an
ecosystem?
2. Look at the pictures below of the cheetahs and
( a single-celled organism).
the paramecium
Then answer the question that follows.
Which of the following statements about the cheetahs and
paramecium is false?
A. These organisms respond to their environment.
B. The cells of these organisms have the same basic
structure.
C. Homeostasis and metabolism are important for the
cheetah
but not for a paramecium.
D. Reproduction means that the organisms will be able to
produce more of their own kind.
3. We sent an unmanned spacecraft to
another planet to detect other life forms that
might be quite different from those on earth. If
the probe can only send back one still picture,
which property of life would be most evident?
A. Living things are organized in cells &
tissues
B. Homeostasis
C. Growth and development
D. Response to stimuli
4. The smallest unit that has all of the
characteristics of life is the
A. Cell
B. Tissue
C. Organ
D. Organism
5. Autotrophs obtain energy
through__________, while heterotrophs obtain
energy through_______.
A. photosynthesis, food eaten
B. decomposition, reproduction
C. food eaten, photosynthesis
D. reproduction, decomposition
6. Growth and/or development is not
observed in the human organism
during
A. childhood
B. adolescence.
C. repair of an injury.
D. death.
7. Which of the following is NOT an example
of a response to a stimulus?
A. A plant growing towards the sunlight.
B. A caterpillar changing into a butterfly.
C. The pupil of the eye changes in size
with changes in light intensity.
D. Stingers are discharged from the
tentacles of a jellyfish when touched.
8. Give one advantage each of sexual and
asexual reproduction.
9. Using a butterfly as an example, compare
and contrast the processes of growth and
development.
10. Define homeostasis and give two examples
of homeostasis in living things.