Transcript U7D2 - Evolution

catalyst
For each statement, indicate if you Agree or Disagree.
Do NOT write the questions:
1.Organisms change over time
2.According to evolution, people came from
monkeys.
3.A theory means there is very little evidence to
support it
4.You can either believe in Evolution OR God.
5.Evolution is something that happened in the past –
not now.
6.There is evidence that supports evolution.
7.Evolution can explain why some organisms live and
others die.
Wednesday
Catalyst
How is homologous structure(s) evidence for
evolution?
What biochemical evidence do we use to
defend evolution?
2 men, 2 theories
Lamarck
Charles Darwin
Lamarck
Theory of acquired characteristics
•He said an individual can acquire changes
during its lifetime and pass them on to their
offspring
– Example: a body builder with huge muscles
would pass on the huge muscles to the baby
Lamarck
Original
Short
shortneck
necked
ancestor
Keeps stretching
neck to reach
leaves higher on
tree
and
stretching
and stretching
Long
neck
until neck gets
longer
2 men, 2 theories
Lamarck
Charles Darwin
Charles Darwin
Theory of Natural Selection
variation
heritable
MORE
OVERPRODUCTION
compete
COMPETITION
survive
fit
adaptations
pass on
NATURAL
SELECTION
Dead
giraffe
Darwin
• Survival of the fittest: survival of those best
adapted individuals allows those best
adapted traits to be passed on to offspring
• Over time, the adaptation is seen in a
greater number of individuals in the
population because nature has selected
the trait to help that organism survive.
• Evolution : the theory that species change
over time
• Species: a group of organisms that can breed
and produce fertile offspring
• Variation: a difference exhibited by a member
of a species
• Natural selection: the theory that organisms
with favorable traits are more likely to survive,
reproduce, and pass on their adaptations to
their offspring
• Adaptation: a beneficial trait that enables an
organism to survive and reproduce
Videos
http://www.youtube.com/watch?v=AiTG6T9
pTcM
http://www.youtube.com/watch?v=Sfgg3S0x
nzk
Practice 2: Natural
Selection
U7-14
Read the introduction
&
complete step
10 min.
Mutation is a
random process
but natural
selection is not
Peppermoth Lab
Demonstration of the most ‘fit’ moth!
http://www.youtube.com/watc
h?v=LyRA807djLc
catalyst
1.What was Lamarck’s theory
called?
2.What is Darwin’s theory called?
3.Describe the first organisms on
early Earth!
Mechanisms
U7-6
mechanisms
Changes in gene pool (types of
genes) cause evolution!
•Mutation: can cause changes to a
gene
- IMPORTANT: has to affect sex cells
so the mutations are passed on!
•Variation provides the material for
natural selection to work on!
Speciation
(new species)
when small populations become
isolated
Geographic isolation: two populations
of the same species become
separated by a physical barrier. Over
time, they become two different
species and can no longer interbreed.
Co-Evolution
The evolution of one species
influences the evolution of the other
species.
Co-Evolution
Example
A moth and a flower. They
evolve together so the
moth’s tongue is exactly the
right shape to fit in the flower
and eat the nectar, while
pollinating the flower.
Example
Garter snakes and a roughskinned newt. The snake eats
the newt and the newt has
developed chemicals to
poison the snakes. Some
snakes developed a
mutation to be resistant to
the poison so they can eat
the newts.
mimicry
"To mimic = to copy"
•When organisms have evolved to share
common characteristics. This adaptation
may increase the fitness of the organism and
allow it to survive better.
* Example: Camouflage and wing patterns in
butterflies
mimicry
mimicry
Mimicry – walking stick
Praying mantis
Chameleon playing dead
The environment
The environment decides which
adaptations are favorable and which
are not. An organism cannot determine
if it will be more fit; it's all up to the
environment!
Pesticide Resistance
* Pesticides are chemicals used to kill insects
that harm crops
* Occasionally, these insects develop
adaptations that make them resistant,
allowing them to survive, reproduce, and
pass on their adaptation onto their offspring
Antibiotic Resistance
* Bacterial infections are treated with drugs
known as Antibiotics
* Some bacteria may have mutations that
make them resistant (don't die) to the
antibiotic
* These bacteria survive, and will go on to
reproduce, so over time, the bacteria
population will no longer die if treated with
an antibiotic
tuberculosis
Antibiotic Resistance
=Least resistant bacteria
=Resistant bacteria
=EXTREMELY resistant bacteria