Chapter 1
The Science of Life

first life arose on earth 3.5 billion years ago
1-1 Study of life =BIOLOGY
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content so vast that specialties have been developed:
o botany study of plants
o
zoology study of animals
o
anatomy study of plant and animal parts
o
taxonomy classification
o
cytology study of cells
o
genetics study of genetics, heredity & DNA
o
physiology study of how things work
o
entomology study of insects
o
herpetology study of amphibians and reptiles
o
mammalogy study of mammals
o
ornithology study of birds
other sciences important to biology:
= chemistry and physics
Anatomy/Botany
herpetology/zoology
zoology/entomology
Biology unified by six themes:
1. Cell Structure and Function

all organisms are made of cells

the cell is the basic unit of life
unicellular = one cell
multicellular= many cells
all surrounded by a membrane and enclosing genetic material (DNA)
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2. Stability and Homeostasis

all living things maintain a stable internal environment (=
homeostasis)
3. Reproduction and Inheritance
reproduction= production of new offspring
DNA= nucleic acid, double helix shape
gene=segment of DNA, unit of hereditary info.

all transmit hereditary information
asexual reproduction= one parent, without egg or sperm
sexual reproduction= two parents, combination of egg and sperm
4. Evolution
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describes changes in populations of organisms over time
natural selection= favorable variations reproduce faster
adaptation= increase’s an organism’s chance at survival
5. Interdependence of Organisms

interactions of organisms with each other and their environment
ecology= study of relationship between organisms and their environment
ecosystems= biotic and abiotic components of an environment
6. Matter, Energy and Organization

organisms require constant supply of energy, the origin of which is the SUN
photosynthesis= light energy is converted to chemical energy
autotrophs= organisms make their own food
heterotrophs= organisms that go and get food
Regents Questions:
1. The arrows in the diagram below indicate the
movement of materials into and out of a singlecelled organism.
The movements indicated by all the arrows are
directly involved in
(1) the maintenance of homeostasis
(2) photosynthesis, only
(3) excretion, only
(4) the digestion of minerals
2. Which process usually results in offspring that
exhibit new genetic variations?(1)
4. The diagram below represents possible
evolutionary relationships between groups of
organisms.
Which statement is a valid conclusion that can
be drawn from the diagram?
(1) Snails appeared on Earth before corals.
(2) Sponges were the last new species to
appear on Earth.
(3) Earthworms and sea stars have a common
ancestor.
(4) Insects are more complex than mammals.
5. The diagram below represents a food web.
3. A food web is represented in the diagram below.
Which population in this food web would most likely
be negatively affected by an increase in the mouse
population?
(1) snake
(3) wolf
(2) rabbit
(4) hawk
Two of the herbivores represented in this food
web are
(1) toads and snakes
(2) deer and mice
(3) wolves and raccoons
(4) grasshoppers and toads
1-2 Characteristics of Life


all living things composed of cells
all living things are highly organized at the cell and molecular level

all living things use energy
metabolism= sum of all of the chemical reactions in living things

all living things maintain stable internal environments
homeostasis= stable conditions of a living thing ( internal)

all living things grow
cell division= making more cells
development= the process by which an organism grows

all species of organisms can reproduce
Cell division: making more cells
Homeostasis: stable conditions of living things
development
_____________________________
Regents Questions:
1. Normally, when the concentration of glucose in the blood falls below a certain level, stored glucose
reenters the blood until the original concentration is reached again. This regulation of the concentration
of blood glucose is part of the process known as
(1) synthesis
(3) pinocytosis
(2) respiration
(4) homeostasis
2. The addition of new cells and corresponding increase in organism size is known as
(1) growth
(3) regulation
(2) transport
(4) respiration
3. Which term is defined as all the chemical reactions that are required to sustain life?
(1) metabolism
(3) nutrition
(2) regulation
(4) synthesis
4. The ability of the human body to maintain a constant body temperature is an example of
(1) transport
(3) homeostasis
(2) metabolism
(4) synthesis
5. Cells are to issues as organs are to
(1) organ systems
(2) cells
(3) genes
(4) organelles
6. A biologist would most likely study all of the chemical activities of an organism to obtain information
about the organism’s
(1) number of mutations
(3) development
(2) reproductive cycle
(4) metabolism
7. Which sequence is listed in order from simplest to most complex?
(1) tissue  cell  organ system  organ
(2) cell  tissue  organ  organ system
(3) cell  tissue  organism  organ
(4) organism  tissue  organ  organ system
1-3 Scientific Methods

many forms, but most similar:
1. define problem/ ask question
2. collect data
= observing, measuring, sampling, organizing information
3. form hypothesis
= suggested explanation that is testable
predicting= educated guess
4. experimenting
= testing a hypothesis by gathering data under controlled conditions
control group= a standard set-up used for comparison
experimental group= the conditions are varied
single variable= independent variable/ dependent variable
5. drawing conclusions


producing a model explanation supported by data
inference= a conclusion based on facts rather than direct observations
6. communicating


report research results (where?)
hypothesis continuously supported by research is termed a theory
Regents Questions:
1. An experiment was performed to determine the effect of different mineral salts on plant growth.
Forty pots containing genetically identical plants were divided into four equal groups and placed in a welllighted greenhouse. Each pot contained an equal amount of non-mineral potting soil and one plant.
Minerals were then added in equal amounts to each experimental group of pots as shown below.
For the experiment to be valid, what should be added to the control group of pots?
(1) water
(3) potassium salts
(2) nitrogen salts
(4) potassium and phosphorus salts
2. The diagram below illustrates the result of growing a garlic bulb in a cup of distilled water over five
days.
Design an experiment consisting of a control and three different experimental groups to test the
prediction, “Garlic grows better as the salt concentration of the solution in which it is grown increases.”
In your answer, be sure to:
• describe the control to be used in the experiment [1]
• describe the difference between the three experimental groups [1]
• state one type of measurement that should be made to determine if the prediction is accurate [1]
• describe one example of experimental results that would support the prediction [1]
Control : The garlic bulb grown in distilled water
Three Experimental groups having different amounts of salt added: for example
Cup 1 3g of salt and water
Cup 2 6g of salt and water
Cup 3 12g of salt and water
Measure the amount of growth in the garlic bulb size
The garlic bulb that grew better in a higher salt concentration.
3. In an investigation designed to determine the effect of the amount of water on plant growth, two groups of
equal-sized bean plants of the same species were grown under identical conditions, except for the amount of water
they were given. One group was watered with 200 milliliters of water once a day, while the other group was
watered with 400 milliliters of water once a day. After several days, the heights of the plants were measured. It
was determined that the plants watered with 400 milliliters of water once a day showed more growth.
The variable in this investigation is the amount of water used
4. A new drug for the treatment of asthma is tested on 100 people. The people are evenly divided into two groups.
One group is given the drug, and the other group is given a glucose pill.
The group that is given the glucose pill serves as the control
The group that is given the drug serves as the experimental
5. A student is designing a procedure to determine the effect of the absence of a specific amino acid in the
nutrient culture medium of a certain species of bacteria. Using one of more complete sentences, describe the
control that the student should use in the experiment.
The control should contain the bacteria grown in a nutrient medium containing the amino acid
6. You are the head of the research division of the Leafy Lettuce Company. Your company is experimenting with
growing lettuce using hydroponic technology. Hydroponic technology involves growing plants in containers of growth
solution in a greenhouse. No soil is used. The growth solution that the company uses contains water, nitrogen, and
phosphorus. The company wants to know if adding iron to this formula will improve lettuce growth.
Briefly describe how to test the effect of the formula with iron added. In your description, be sure to:
a) State a hypothesis to be tested in the new experiment
If Iron is added to the growth solution, then the lettuce will grow better
b) State how the control group will be treated differently from the experimental group.
The control group contains the lettuce grown in growth solution NOT containing Iron.
c) Identify two factors that must be kept the same in both the experimental and control groups.
Amount of water used, amount of light exposure, amount of growth solution given, type and number
of lettuce plants tested etc.
d) State what types of data should be collected to support or refute the hypothesis.
SUPPORT: If the lettuce is was grown in growth solution containing Iron it grew better.
REFUTE: If the lettuce is was grown in growth solution containing Iron it did not grow better.
____ 7. Which condition is necessary for an experiment to yield useful data?
(a) similar results should be obtained when the experiment if repeated
(b) only the expected results should be considered each time experiment is performed
(c) the hypothesis is correct
(d) the experimental period must be short
____ 8. An organism was kept at a temperature of 40 oC for a period of 2 weeks. At the end of that
time, the investigator determined that the organism was sterile. To support the hypothesis that
high temperatures cause sterility, the investigator should be able to show that the
(a) organism was not sterile before the experimental period began
(b) high temperature did not alter the blood pressure of the organism
(c) pituitary gland, which controls sterility, of the organism had not degenerated
(d) organism was homozygous for temperature sensitivity
____ 9. A nutrient medium was prepared by mixing powdered agar with boiling distilled water. Some of
the prepared medium was then placed in a sterile petri dish, covered, and allowed to solidify. The
cover was then removed and the agar was touched to a door knob. The petri dish was covered
again and incubated at 37 oC. After 48 hours, bacterial growth was observed. The investigator
concluded that bacteria on doorknobs cause disease. One error was that the investigator
(a) used distilled water
(b) covered the petri dish
(c) did not show that bacteria caused disease
(d) did not incubate the materials at the proper temperature
____ 10. A student conducted an original, well-designed experiment, carefully following proper scientific
procedure. In order for the conclusions to become generally accepted, the experiment must
(a) contain several experimental variables
(b) be repeated to verify the reliability of the data
(c) support the original hypothesis
(d) be conducted by a scientist
____ 11. In a controlled experiment, 20 marigold plants of the same age were grown singly in 20
different pots containing soil of the same composition and moisture level. The pots were divided
into two groups of 10. One group was exposed to 8 hours of sunlight each day for 15 days, and the
other group was exposed to 8 hours of light from a 75-watt bulb for the same period. In this
investigation, the source of light represents the experimental
(a) problem
(b) control
(c) hypothesis
(d) variable
____ 12. Which experimental procedure would best determine the effectiveness of a vaccine for
preventing a certain disease in pigeons?
(a) Expose 100 pigeons to the disease and then inoculate all 100 pigeons with the vaccine.
(b) Expose 100 pigeons to the disease and then inoculate 50 of these pigeons for this disease.
(c) Inoculate 10 pigeons with the vaccine and 90 pigeons with a harmless solution and then expose
all 100 pigeons to the disease.
(d) Inoculate 50 pigeons with the vaccine and 50 pigeons with a harmless solution and then
expose all 100 pigeons to the disease.
A student conducting an experiment placed five geranium plants of equal size in environmental chambers.
Growing conditions were the same for each plant except that each chamber was illuminated by a
different color of light of the same intensity. At the end of 20 days, plant growth was measured.
13. Using one or more complete sentences, state a possible hypothesis for this experiment.
ONE POSSIBLE HYPOTHESIS: If geranium plants are grown in red light they will grow better.
14. Using one or more complete sentences, state the control that should be used in this experiment.
CONTROL: Geranium plants grown in sunlight or Geranium plants grown under a white light bulb
A sterile petri dish, A, containing sterile nutrient agar was exposed to the air for a few minutes. A
second sterile petri dish, B, containing sterile nutrient agar was not opened. Both petri dishes were
placed in a warm, dark place. Three days later, petri dish A was observed to contain a population of
bacteria, which petri dish B had no bacterial growth.
15. Using one or more complete sentences, explain how petri dish B serves as a control for the
experiment.
Petri Dish B is the control because it was not exposed to the air.
16. Using one or more complete sentences, state a hypothesis that this experiment could have been
testing using petri dish B as the control.
POSSIBLE HYPOTHESIS: If a petri dish is exposed to air then bacteria will grow on it.
17. A scientist performed an experiment using the following steps:
Define and
research the
problem
X
Set up and
Make
conduct the
observations
experiment once
and record data
Formulate a
conclusion
Repeat the
experiment
Using one or more complete sentences, identify the step that belongs in box X.
X= State a Hypothesis
The diagram below shows fours setups used in an attempt to investigate the release of a gas during
photosynthesis. Each setup was maintained at 25 oC for a period of 10 hours.
18. Using a complete sentence, state the problem of this experiment.
PROBLEM : I want to know if plants exposed to light will produce gas during photosynthesis.
19. Using a complete sentence, state a hypothesis.
POSSIBLE HYPOTHESIS: If I expose plants to sunlight then they will produce gas during
photosynthesis.
20. What were the variable and the control for this experiment?
VARIABLE: the plant
CONTROL: The plant under the glass tube with light
1-4 Microscopy and Measurement
Microscopes
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
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1590 Janssen Brothers
o first compound microscope
van Leeuwenhoek
o fish tail capillaries
o “wee beasties” in fresh water (initial study of microbiology)
our compound microscopes are called light microscopes
parts of microscope (diagram sheet) and their functions
o lenses:
1. eyepiece lens: 10x
2. objective lenses:
very low:
5x (total=50X)
low:
10x (total= 100X)
high:
43x (total=430X)

oil:
97x (total=970X)
light microscopes limited to 2000x

why? The wave length of light only allows us to see object at 2000X or less
resolution drops with increase in magnification

resolution= the ability to see detail in a in/on an object under the microsope
unit of measure = μ micron (SI unit of length measurement)
= 0.000001m
1 millimeter = 1,000 microns
TEM’s: Transmission Electron Microscopes
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

use electrons in place of light
focus with magnets
electron beam passes through thin section of object (therefore not alive)
magnifies 200,000x: photo enlarged 5x: total= 1,000,000X
(no resolution problems)
SEM’s: Scanning Electron Microscopes


shows surface of object in 3D
allows very high magnification
Other Tools of the Biologist
Ultra Centrifuge
ex. separating blood or urine samples
ex. separating cell components
 based on density
Chromatography
 paper
 column
Electrophoresis
 gel
X-ray Diffraction
 used with large molecules or crystals
ex. discovery of DNA structure
Computers
 data management
Regents Questions:
1. The four wells represented in the diagram were
each injected with fragments that were prepared
from DNA samples using identical techniques.
2. A laboratory technique is illustrated in the
diagram below.
This laboratory procedure is known as
(1) cloning
(2) gel electrophoresis
(3) chromatography
(4) use of a dichotomous key
This technique is used to
(1) determine volume
(2) separate molecules in a mixture
(3) measure length
(4) analyze data from an experiment
3. DNA electrophoresis is used to study evolutionary relationships of species. The diagram below shows
the results of DNA electrophoresis for four different animal species.
Which species has the most DNA in common with species A?
(1) X and Y, only
(3) Z, only
(2) Y, only
(4) X, Y, and Z