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Transcript
Introduction to Biology
1
Biology – The Study of Life
•
•
•
•
Section 1: The World of Biology
Section 2: Themes in Biology
Section 3: The Study of Biology
(Section 4: Tools and Techniques ~ will
be covered in separate power point)
HUTCHCROFT
Introduction to Biology
• Biology: The study of life
•
Life arose more than 3.5 billion years ago
in Archean eon of Precambrian period
• First organisms (living things) were single celled
(unicellular); Only life on Earth for millions of
years
• First multicellular organisms arose in the
Proterozoic eon of Precambrian period between
550 million and 2.5 billion years ago!
•Organisms changed over time (evolved)
Introduction to Biology
• New organisms arose from older kinds !
Today, estimates suggest 10 – 100
million organisms may exist!!!!!!!!! Only
1.5 million of these have been named!
• 99% of organisms that EVER existed may
already be extinct, having never been identified
and named!!
• 99% of all animal species are smaller than
bumble bees!
• Organisms inhabit almost EVERY region
of the Earth today!
The World of Biology
• Biology: The study of life
• Characteristics of life
• Organization and Cells
• Response to Stimuli
• Homeostasis
• Metabolism
• Growth and Development
• Reproduction
• Change Through Time
Organization and Cells
•
•
•
•
•
All living things are composed of
one or more cells
Cells are the smallest units that
can perform all life’s processes
In multicellular organisms, many
are specialized to perform
specific functions
Cells are always very small
The size of multi-celled
organisms depends on the
number of cells NOT their size
Organization and Cells, cont.
•
•
•
Organized at both the
molecular and cellular
levels
Take in substances from
the environment and
organize them in complex
ways
Specific cell structures
(organelles) carry out
particular functions
•
In multicellular organisms, cells and groups of cells are
organized by their function (hierarchy of life)
• Atom  Biological Molecule  Organelle  Cell 
Tissue  Organ  Organ System  Organism
I don’t care what you say – that’s
funny right there!!! LOL!!
Want more? How about the whole
hierarchy of Life from the organism on……
1st Level of Organization
• Organism:
An individual living
thing that is made of
cells, uses energy,
reproduces, responds,
grows, and develops
2nd Level of Organization
• Population:
A group of
organisms, all of the
same species, which
interbreed and live
in the same place at
the same time.
3rd Level of Organization
• Biological
Community:
All the populations of
different species that live in
the same place at the same
time and interact (solely
biotic in terms of
composition).
4th Level of Organization
• Ecosystem: Populations
of plants and animals that
interact with each other in a
given area, along with the
abiotic components (physical
and chemical) of that area.
[terrestrial or aquatic]
• Biosphere:
5th Level of Organization
•Earth:apple::biosphere:skin of apple
Broadest, most
inclusive level, i.e., the
thin volume of Earth
and its atmosphere that
supports life (5 to 6
miles above surface to
deepest part of the
oceans)
Response to Stimuli
•
Organisms can respond to a stimulus, or a
physical or chemical change in the
internal or external environment
Homeostasis
• The maintenance of a stable level of internal
conditions even though environmental conditions are
constantly changing, e.g., body temperature, water
content, glucose levels
Metabolism
• The sum of all the chemical reactions that take in and
transform energy and materials from the environment
PHOTOSYNTHESIS
Metabolism
• ALL energy comes from the SUN (directly or
indirectly)
• Photosynthesis is the process by which some
organisms capture the energy from the sun (solar)
and transform it into energy (chemical) that can
be used by living things
PHOTOSYNTHESIS
Metabolism
• Organisms that make their own food are called
autotrophs
• Phototrophs – use solar energy (photosynthesis) to
get energy
• Convert H2O and CO2 into sugar and O2
• Chemotrophs – use different chemical processes to
get energy
• Organisms that must take in food to meet their
energy needs are called heterotrophs
Consume autotrophs (herbivores), other
heterotrophs (carnivores) or both (omnivores) for
their energy needs
• Complex chemicals are broken down and
reassembled into chemicals and structures needed
by organisms
Growth and Development
• All living things grow and increase in size from the
division and enlargement of cells
• Development is the process by which an organism
becomes a mature adult; involves cell division and c
differentiation, or specialization
Reproduction
• Production of new organisms is essential for the
continuation of a species
• Hereditary information is transferred to offspring
during two kinds of reproduction
• Sexual reproduction – hereditary information
recombines from two organisms of the same
species
• Asexual reproduction – hereditary information
from different organisms is not combined ~
original and new organisms are genetically the same
Evolution or Change Through Time
• Populations of living organisms evolve or change
through time to better adapt to changing conditions
• Charles Darwin’s SURVIVAL OF THE FITTEST
through the process of natural selection
THEMES IN BIOLOGY
• Diversity and Unity
• Unity in the Diversity of Life
• Three Domains of Life
• Interdependence of Organisms
• Evolution of Life
• Natural Selection
Unity in the Diversity of Life
• Genetic code: rules that govern how cells use the
hereditary information in DNA (deoxyribonucleic acid
– makes up our genes or instructions for life)
• Presence of organelles: carry out all cellular
activities
• “Tree of Life” – suggests all living things have
descended with modification from a single common
ancestor; thus, all of life is connected
Three Domains of Life
• Bacteria
• Kingdom
• Archaea
• Kingdom
• Eukarya
• Kingdom
• Kingdom
• Kingdom
• Kingdom
Bacteria (Eubacteria)
Archaea (Archaebacteria)
Animalia
Plantae
Fungi
Protists
Interdependence of Organisms
• Ecology: branch of biology that studies organisms
interacting with each other and with the environment
• Ecosystems: communities of living species and their
physical environments; e.g., minerals, nutrients, water,
gases, heat, etc.
Evolution of Life
• Descent with modification: process in which the
inherited characteristics within populations change
over generations, such that genetically distinct
populations and new species can develop
• Natural Selection: organisms that have certain
favorable traits are better able to survive and
reproduce successfully than organisms that lack
these traits
• Adaptations: traits that improve an individual’s
ability to survive and reproduce
Scientific Method
Scientific Processes and Methods
• 1. Observations/Questioning
• 2. Measuring, Organizing Data, and Classifying
• 3. Hypothesizing -- a testable explanation based
on experience, reading, and/or previous
experiments. (NOT A GUESS)
• Inductive Reasoning
• 4. Predicting -- stating in advance the result that
will be obtained from testing
• Deductive Reasoning (If…then…statement)
Scientific Method, cont.
• 5. Experimenting -- A controlled procedure for
testing a hypothesis
• Control Group -- all conditions remain constant
• Experimental Group -- same as control, except
for ONE factor
• Variable
• Independent Variable - condition that
changes
• Dependent Variable - response to changed
condition
• Data
• Qualitative ~ descriptive
• Quantitative ~ numbers
Scientific Method, cont.
Scientific Method, cont.
• 6. Organizing and Analyzing Data
Scientific Method, cont.
• 7. Inferring Conclusions (concluding
from evidence collected during
experimentation using facts and
previous knowledge rather than direct
observtions)
• 8. Modeling and Communicating
• 9. Test and Re-test ~ law or theory
formed
Scientific Method, cont.
• LAW -- general statement that describes a wide
variety of phenomena
• If a hypothesis describes HOW things happen
and continues to be supported by evidence, it
becomes a law.
• THEORY -- most probable explanation for a set of
data based on best available evidence
• If a hypothesis describes WHY things happen
and continues to be supported by evidence, it
becomes a theory.
Scientific Method -- Example
• Observations:
• Fish populations in Twin Lakes are declining.
• The pH (acidity) of the water in the lakes is
dropping to 4.2.
• One hundred miles west of Twin Lakes is a power
plant that is burning tons of coal every year,
releasing sulfur dioxide into the air.
Problem
• Twin Lakes -- Acid Rain Problem
100
miles
Power
Plant
West
Branch
East
Branch
Questioning/Hypothesizing
(Inductive Reasoning)
• Question: Is there a link between the
power plant, the pH of the lake, and the
fish decline?
• Hypothesis: If acid rain falling on Twin
Lakes is related to fish reproduction, then
increasing acid rain amounts will cause
the fish to have poor reproduction.
Experiment
• Experiment
• Twin Lakes is a lake in the mountains that can be
divided by a barrier.
• A complete inventory will gather baseline data.
• One arm of the lake, on the east side of the barrier,
will be treated with sulfuric acid to reduce the pH to
4.0.
• The west arm of the lake will be left alone, other
than monitoring.
Experiment
• Twin Lakes -- Acid Rain Problem
100
miles
East
Branch
West
Branch
Barrier
Power
Plant
No Acid Added
Acid Rain Added
Results
• East Branch:
• Fish stop reproducing.
• West Branch:
• No change in fish reproduction.
Conclusion
• The power plant emits sulfur dioxide into
the air which combines with rain to
produce acid rain. The addition of this
acidic rain to the lakes lowers the pH and
causes the fish to stop reproducing. This
results in declining fish populations and
jeopardizes the survival of the fish.