Transcript Biology concepts

Biology Concepts
1.1 What is life?
What is life?
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Living things vs. nonliving objects:
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Comprised of the same chemical elements
Obey the same physical and chemical laws
The cell is the smallest, most basic unit of all life
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Familiar organisms are multicellular
Some cells independent – single-celled organisms
What are emergent properties?
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Levels range from
extreme micro to
global
Each level up:
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More complex than
preceding level
Properties:
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A superset of
preceding level’s
properties
Emerge from
interactions between
components
What are the basic requirements of all living things?
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Three requirements
 Materials and Energy
 Reproduction and Development
 Adaptations and Natural Selection
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Energy - the capacity to do work
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The sun:
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Metabolism - all the chemical reactions
in a cell
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Ultimate source of energy for nearly all life
on Earth
Drives photosynthesis
Homeostasis - Maintenance of internal
conditions within certain boundaries
Acquiring nutrients
What are the basic requirements of all living things?
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Living things detect changes in
environment
Response often involves
movement
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Vulture can detect and find carrion
a mile away
Monarch butterfly senses fall and
migrates south
Microroganisms follow light or
chemicals
Even leaves of plants follow sun
Responses collectively constitute
behavior
What are the basic requirements of all living things?
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Organisms live and die
Must reproduce to
maintain population
Multicellular organisms:
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Begins with union of
sperm and egg
Developmental
instructions encoded in
genes
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Composed of DNA
Long spiral molecule in
chromosomes
What are the basic requirements of all living things?
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Adaptation
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Any modification that makes an
organism more suited to its way
of life
Organisms, become modified
over time
However, organisms very similar
at basic level
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Suggests living things descended
from same ancestor
Descent with modification Evolution
Caused by natural selection
Biological Concepts
1.2 Taxonomy and Systematics
What is taxonomy?
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The rules for identifying and classifying organisms
Hierarchical levels (taxa) based on hypothesized evolutionary relationships
Levels are, from least inclusive to most inclusive:
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Species, genus, family, order, class, phylum, kingdom, and domain
A level usually includes more species than the level below it, and fewer species
than the one above it
How are organisms classified?
What are the three domains?
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Bacteria
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Archaea
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Microscopic unicellular prokaryotes
Bacteria-like unicellular prokaryotes
Extreme aquatic environments
Eukarya
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Eukaryotes – Familiar organisms
What are the kingdoms?
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Archaea –
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Bacteria –
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Kingdoms still being
worked out
Kingdoms still being
worked out
Eukarya
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Kingdom Protista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
What are scientific names?
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Binomial nomenclature (two-word
names)
Universal
Latin-based
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First word represents genus of
organism
Second word is specific epithet of a
species within the genus
Always Italicized as Genus species
(Homo sapiens)
Genus may occur alone (Homo), but
not specific epithet
Biological Concepts
1.3 Scientific method
What is the scientific method?
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Begins with observation
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Scientists use their five
senses
Instruments can extend
the range of senses
Hypothesis
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A tentative explanation
for what was observed
Developed through
inductively reasoning
from specific to general
What is the scientific method?
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Experimentation
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Purpose is to challenge
the hypothesis
Designed through
deductively reasoning
from general to specific
Often divides subjects
into a control group and
an experimental group
Predicts how groups
should differ if
hypothesis is valid
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If prediction happens,
hypothesis is
unchallenged
If not, hypothesis is
unsupportable
What is the scientific method?
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Results
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Observable, objective
results from an experiment
Strength of the data
expressed in probabilities
The probability that
random variation could
have caused the results
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Low probability (less than
5%) is good
Higher probabilities make it
difficult to dismiss random
chance as the sole cause of
the results
What is the scientific method?
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The results are analyzed
and interpreted
Conclusions are what the
scientist thinks caused the
results
Findings must be reported
in scientific journals
Peers review the findings
and the conclusions
Other scientists then
attempt to duplicate or
dismiss the published
findings
What is a scientific theory?
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Scientific Theory:
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Joins together two or more
related hypotheses
Supported by broad range
of observations,
experiments, and data
Scientific Principle / Law:
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Widely accepted set of
theories
No serious challenges to
validity
What types of experimental variables are there?
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Experimental
(Independent) variable
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Applied one way to
experimental group
Applied a different way
to control group
Response (dependent)
variable
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Variable that is
measured to generate
data
Expected to yield
different results in
control versus
experimental groups