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Biology is the study of life!!!
Biodiversity
• What is life?
–
-
Organisms are composed of cells
Living things are organized
Growth (cells and numbers of cells)
Development
Acquire energy (and transform it)
Movement
Respond to stimuli
Reproduce
–
Over a million animal
species have been described
all organisms need to solve life’s
problems
• acquire energy
• eliminate wastes
• water balance
• reproduce
• get oxygen to all cells
Different adaptations have developed in
different critters to solve life’s problems!
•
Evolution: the primary unifying
concept of biology!!!
• Evolution
– Evolution is the genetic change in
a population over time.
– Evolution is the genetic change in
a population over time.
- Genetic make-up provided by parents
- Genetic make-up provided by parents
Pa
Ma
Evolution = change in genetic make-up of a
population (England 1850’s)
• Evolution
– Evolution is the genetic change in
a population over time.
- Genetic make-up provided by parents
Junior differs
from others in population
Junior
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• change in genetic make-up of population?
• change in genetic make-up of population
2
3
• change in genetic make-up of
population
• change in genetic make-up of
population -
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4
Our understanding of evolution is
based on science
• So what is science?
- Knowledge gathered from questions
based on observations
i.e., Scientific inquiry begins with questions
based on observations
• How do you decide which questions can
be answered scientifically?
• Questions can be answered scientifically
if the question (hypothesis) can be
experimentally tested and shown to be
false (a falsifiable hypothesis).
Falsifiable hypothesis? One in which
we have the ability to say NO or False
To do this we use the Scientific Method
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Scientific Method:
Observations
Observations
(brightly colored coral
snakes + strawberry frogs
are poisonous)
(all brightly colored organisms
are poisonous)
Hypothesis
Hypothesis (question)
Predictions (if I feed my girl friend strawberries
she will die)
Predictions
Test
Test
(feed her strawberries - no death)
(experiment)
Conclusions
(reject the hypothesis)
Conclusions
Observations
(brightly colored coral
snakes + strawberry frogs
are poisonous)
(all brightly colored organisms
Hypothesis
are poisonous)
(if I feed my girlfriend strawberries
she will die)
Predictions
Test
(feed her strawberries -
Conclusions
She Dies!!!!
• she dies - so we accept the hypothesis.
Did we prove that all brightly colored
organisms are poisonous?
No - maybe something else killed
her (not the strawberries)
Science advances by showing that
a hypothesis is false
(accept the hypothesis?)
Observations
Plant dies in dorm!
Observations
Plant dies in dorm!
Hypothesis
• Didn’t water it enough
Hypothesis
• Didn’t water it enough
Predictions
• If add more water it will live
Predictions
• If add more water it will live
• Water 50 same/50 with more H2O
•
dies
/
dies
Test
Test
Conclusions?
Reject hypothesis
• Water 50 same/ 50 with more H2O
•
all die
/
all live!!!!!
Conclusions?
Accept hypothesis
(Something else is killing the plants!)
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Did we prove that lack of water killed
the first plant or the plants after them?
No!!
Something other than what we tested
may have killed the plants or enabled
the second group of plants to live.
- We accept hypotheses conditionally
(Future studies may reject this hypothesis)
• Can all questions be answered
scientifically?
- Is ballet better than ice figure skating ?
- What is the cause of aids?
- Does cigarette smoking cause cancer?
- What is the best recipe for lasagna?
- Is Michael Jordan the best basketball player
that ever lived?
- Can predators regulate the size of a prey
population?
Can each of these be systematically measured
in an way that all can accept and repeat?
Theories
Remember three important points:
1. Science advances by disproving hypotheses
• A theory is a hypothesis that is supported
by a good deal of evidence
Ii.e., we haven’t been able to reject the
hypothesis after many many studies.
2. Hypotheses are only accepted conditionally
3. Not all questions can be addressed using the
scientific method
• Contrast with public’s understanding of
a theory
- Theory of evolution -
Science is based on ethics
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