Transcript Biology Ch. 1 notes

Biology: Chapter One
The Science of Biology
The Goal of Science
 Investigate and
understand nature
 Explain events in
nature
 Use those
explanations to make
useful predictions
Observations
 An observation involves using one or more of
the senses to gather information. This
evidence is called data.
 Quantitative observations involves numbers,
such as measurements.
 Qualitative observations involve
characteristics that cannot easily be measured
or counted, such as texture and color.
Inferences
 An inference is a logical interpretation of
an observation based on prior knowledge
and experience.
Observation and Inference
Statement
Object A is round and orange.
Observation Inference
X
X
Object A is a basketball.
Object C is round and black and white.
X
Object C is larger than Object B.
X
Object B is smooth.
X
X


X
Object B is a table-tennis ball.
Each object is used in a different sport.

X
Object A is a
basketball.
Object B is a tabletennis ball.
Object C is a soccer
ball.
Scientific Method
 State the problem
 Form a hypothesis (educated guess that must be
testable).
 Design a controlled experiment.
 Record and analyze data.
 Form a conclusion
 When a hypothesis is well-supported, it may be
consider to be a theory. A theory is a well-tested
explanation that unites a broad range of observations.
Section 1-2
Designing an Experiment
State the Problem
Analyze Results
Form a Hypothesis
Draw a Conclusion
Set Up a Controlled Experiment
Publish Results
Record Results
Experimental variables
 An independent variable is the variable
that is changed in a scientific experiment.
 A dependent variable is the variable
being tested in a scientific experiment.
 As the experimenter changes the
independent variable, the change in the
dependent variable is observed and
recorded.
Example: Fertilizer vs. Plant
Growth
 In a study measuring the
influence of different quantities
of fertilizer on plant growth, the
independent variable would be
the amount of fertilizer used.
 The dependent variable would
be the growth in height or
mass of the plant.
 The controlled variables would
be the type of plant, the type of
fertilizer, the amount of
sunlight the plant gets, the size
of the pots, etc.
Characteristics of Living Things








Made up of cells
Reproduce
Based on universal genetic code
Grow and develop
Obtain and use materials and energy
Respond to the environment
Maintain a stable internal environment
Change over time as a group
Characteristics of Living Things
CHARACTERISTICS OF LIVING THINGS
Characteristic
Examples
Living things are made up of units called
cells.
Living things reproduce.
Living things obtain and use materials and
energy.
Many microorganisms consist of only a single cell.
Animals and trees are multicellular.
Maple trees reproduce sexually. A hydra can
reproduce asexually by budding.
Flies produce flies. Dogs produce dogs. Seeds from
maple trees produce maple trees.
Flies begin life as eggs, then become maggots, and
then become adult flies.
Plants obtain their energy from sunlight. Animals
obtain their energy from the food they eat.
Living things respond to their environment.
Leaves and stems of plants grow toward light.
Living things maintain a stable internal
environment.
Despite changes in the temperature of the
environment, a robin maintains a constant body
temperature.
Taken as a group, living things change
over time.
Plants that live in the desert survive because they have
become adapted to the conditions of the desert.
Living things are based on a universal
genetic code.
Living things grow and develop.
Cells are the basic unit of life
 Unicellular
organisms are made
up of one cell.
Example: amoeba
 Multicellular
organisms are made
up of diverse cells.
Cells are specialized
in some organisms to
perform a different
function. Example:
plants and animals
Reproduction
Budding hydra
 Asexual reproduction
requires a single parent
to produce a new
organism.
 Sexual reproduction
requires two cells from
different parents to join
to form the first cell of
the new organism.
 The genetic code
transferred during
reproduction determines
the inherited traits of
every organism on
Earth.
 Metabolism is the combination of
chemical reactions through which an
organism builds up or breaks down
materials.
 Homeostasis is the process by which
organisms keep their internal conditions
relatively stable. If this process is
disrupted in a major way, the organism
cannot survive.
 Evolution describes the changes in a
group of organisms over time.
Branches of Biology
 “Biology” means the “study of life”.
 The divisions of biology are based on the
types of organisms being studied.
 For example: zoology is the study of
animals, botany is the study of plants,
and microbiology is the study of
microorganisms such as bacteria.
Levels of Organization
 The many levels at which live can be
studied include the following:
MOLECULES, CELLS, GROUPS OF
CELLS and ORGANISMS,
POPULATIONS, COMMUNITIES,
ECOSYSTEMS, and the BIOSPHERE
(Planet Earth)
Figure 1-21 Levels of Organization
Biosphere
Ecosystem
The part of Earth
that contains all
ecosystems
Biosphere
Community and
its nonliving
surroundings
Hawk, snake, bison, prairie dog, grass, stream, rocks, air
Community
Populations that
live together in a
defined area
Hawk, snake, bison, prairie dog, grass
Population
Group of
organisms of
one
type that live in
the same area
Bison herd
Figure 1-21 Levels of Organization continued
Organism
Individual living
thing
Bison
Bison
Groups of
Cells
Tissues, organs,
and organ systems
Nervous tissue
Brain
Nervous system
Cells
Smallest functional
unit of life
Molecules
Go to
Section:
Groups of atoms;
smallest unit of
most chemical
compounds
Nerve cell
DNA
Water