Post on 15-Jan-2016
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Biology Concepts
1.1 What is life?
What is life? Living things vs. nonliving objects:
Comprised of the same chemical elements Obey the same physical and chemical laws
The cell is the smallest, most basic unit of all life Familiar organisms are multicellular Some cells independent – single-celled organisms
What are emergent properties? Levels range from
extreme micro to global
Each level up: More complex than
preceding level Properties:
A superset of preceding level’s properties
Emerge from interactions between components
What are the basic requirements of all living things? Three requirements
Materials and Energy Reproduction and Development Adaptations and Natural Selection
Energy - the capacity to do work The sun:
Ultimate source of energy for nearly all life on Earth
Drives photosynthesis Metabolism - all the chemical reactions
in a cell Homeostasis - Maintenance of internal
conditions within certain boundaries Acquiring nutrients
What are the basic requirements of all living things? Living things detect changes in
environment Response often involves
movement 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? Organisms live and die Must reproduce to
maintain population Multicellular organisms:
Begins with union of sperm and egg
Developmental instructions encoded in genes Composed of DNA Long spiral molecule in
chromosomes
What are the basic requirements of all living things? Adaptation
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 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? The rules for identifying and classifying organisms Hierarchical levels (taxa) based on hypothesized evolutionary relationships Levels are, from least inclusive to most inclusive:
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? Bacteria
Microscopic unicellular prokaryotes Archaea
Bacteria-like unicellular prokaryotes Extreme aquatic environments
Eukarya Eukaryotes – Familiar organisms
What are the kingdoms? Archaea –
Kingdoms still being worked out
Bacteria – Kingdoms still being
worked out Eukarya
Kingdom Protista Kingdom Fungi Kingdom Plantae Kingdom Animalia
What are scientific names? Binomial nomenclature (two-word
names) Universal Latin-based
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? Begins with observation
Scientists use their five senses
Instruments can extend the range of senses
Hypothesis A tentative explanation
for what was observed Developed through
inductively reasoning from specific to general
What is the scientific method? Experimentation
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
If prediction happens, hypothesis is unchallenged
If not, hypothesis is unsupportable
What is the scientific method? Results
Observable, objective results from an experiment
Strength of the data expressed in probabilities
The probability that random variation could have caused the results 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? 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? Scientific Theory:
Joins together two or more related hypotheses
Supported by broad range of observations, experiments, and data
Scientific Principle / Law: Widely accepted set of
theories No serious challenges to
validity
What types of experimental variables are there? Experimental
(Independent) variable Applied one way to
experimental group Applied a different way
to control group Response (dependent)
variable Variable that is
measured to generate data
Expected to yield different results in control versus experimental groups