Living Environment
Part D (Required Labs)
Review
Beaks of Finches
 14
Species of Darwin’s finches
– Beaks vary in size and shape
– Bodies vary in size and shape
Beaks of Finches
 Different
beak sizes and shapes
differ in their efficiency at performing
particular tasks.
Beaks of Finches
 Why
do offspring of better-adapted
individuals inherit many of their
parents’ favorable variations?
Beaks of Finches
 Why
do offspring of better-adapted
individuals inherit many of their
parents’ favorable variations?
– Favorable variations allow parents
to survive and then reproduce
more. Their offspring then may
possess those variations.
Beaks of Finches
 What
are the parts of Darwin’s
theory of Natural Selection?
Beaks of Finches

What are the parts of Darwin’s theory of
Natural Selection?
–OVCSR
Only (Overproduction)
Vince (Variation)
Can (Competition)
Suck (Survival of the Fittest)
Rutabegas (Reproduction)
Beaks of Finches
 Variation

means ______________.
Why do the finches of the Galapagos
Islands show so much variation?
Beaks of Finches
 Variation

means _differences___.
Why do the finches of the Galapagos
Islands show so much variation?
– Each finch species adapted to their
different environments.
Beaks of Finches
 What
did the tools represent?
Beaks of Finches
 What
did the tools represent?
– The different beak shapes.
Beaks of Finches
 What
did the different seeds
represent?
Beaks of Finches
 What
did the different seeds
represent?
 The
different types of food available on
the island.
Beaks of Finches
 Why
are the 4 trials completed and
then averaged for each of the
“feedings”?
Beaks of Finches
 Why
are the 4 trials completed and
then averaged for each of the
“feedings”?
The
data is more
accurate when the trials
are averaged.
Beaks of Finches
 All
of the finches have similarities.
Why is this the case?
Beaks of Finches
 All
of the finches have similarities.
Why is this the case?
– All of the finches share a common
ancestor.
Relationships and Biodiversity
 Botana
curus (fictional plant for lab
purposes) produces Curol.
– This was supposedly used to
________________.
Relationships and Biodiversity
 Botana
curus (fictional plant for lab
purposes) produces Curol.
– This was supposedly used to cure
cancer.
Relationships and Biodiversity
The plants used in the lab, and what
they were modeled after… maybe?
This is the Pacific Yew.
It contains “Taxol” –
used to treat cancer.
This is what was
used in the lab,
though.
Relationships and Biodiversity
 Why
was it necessary to find an
alternative to Botana Curus?
 Story
of Taxol
Relationships and Biodiversity
 Why
was it necessary to find an
alternative to Botana Curus?
http://www.phcog.org/Taxus/Taxus_Web.html
 In
the lab, the plant was endangered
and was in short supply.
 (In
reality, the Pacific Yew only
produces one dose of drug per tree!
Scientists wanted to find an
alternative!)
Relationships and Biodiversity
 Chromatography:
Sorts
molecules
based on ____
Relationships and Biodiversity
 Chromatography:
Sorts
molecules
based on SIZE.
The smaller molecules
move faster up the
paper. Larger ones move
slower and stay toward
the bottom of the paper.
Relationships and Biodiversity
 What
is an indicator?
Relationships and Biodiversity
 What
is an indicator?
They are used to detect certain
substances.
In the lab, we used a white powder to
test for “Enzyme M”.
Relationships and Biodiversity
 Gel
Electrophoresis:
 Used for: ___________________
The top indicates the DNA sources.
This side
indicates how
many base pairs
are in the DNA
fragments.
Relationships and Biodiversity
 Gel
Electrophoresis:
 Used for: Comparing DNA samples
The top indicates the DNA sources.
This side
indicates how
many base pairs
are in the DNA
fragments.
Relationships and Biodiversity
 Gel
Electrophoresis:
The DNA fragments
are sorted based
on __________
Relationships and Biodiversity
 Gel
Electrophoresis:
The DNA fragments
are sorted based
on SIZE.
An electrical current
pulls the smaller
fragments through
the “gel” faster than
the larger
fragments.
Relationships and Biodiversity
 Gel
Electrophoresis:
The original samples of DNA are
“cut” using RESTRICTION
ENZYMES.
In the lab, you simulated this by
using scissors to cut paper DNA.
Relationships and Biodiversity
 mRNA
codons code for amino acids
 Example:
– DNA code: CGA AAA GTC
– mRNA code: GCU UUU CAG
– Amino acid chain: (on next page)
 Alanine,
Phenylalanine, Glutamine
Relationships and Biodiversity
 What
causes extinction and loss of
biodiversity?
Relationships and Biodiversity
 What
causes extinction and loss of
biodiversity?
 Change
in environment
 Disease
 Human
activities (pollution,
deforestation)
 Overuse of resources (competion)
Relationships and Biodiversity
 Loss
of biodiversity may be a
warning of what?
Relationships and Biodiversity
 Loss
of biodiversity may be a
warning of what?
 Extinction
 Unstable
environment
Relationships and Biodiversity
 Benefits
of biodiversity:
Relationships and Biodiversity
 Benefits
 More
of biodiversity:
food sources for consumers
 Less chance of extinction
 Medicinal resources
 More stable ecosystem
Diffusion Through a Membrane
 What
causes the process of
diffusion?
Diffusion Through a Membrane
 What
causes the process of
diffusion?
The particles (molecules) move
down a concentration gradient from
high concentration to low
concentration.
This happens because as molecules
bump into each other, they are
forced to spread out to where there
aren’t as many molecules to bump
into.
Diffusion Through a Membrane
 If
certain molecules encounter
membranes with pores, what can
happen?
Diffusion Through a Membrane
 If
certain molecules encounter
membranes with pores, what can
If the molecules (particles) are small
happen?
enough, they will pass through the
pores in the membrane.
If they are too big, they cannot pass
through the pore.
SELECTIVE
PERMEABILITY. Cell
This is called
membranes are selectively
permeable.
Diffusion Through a Membrane
 What
was different between your
model and a real cell?
Diffusion Through a Membrane
 What
was different between your
model and a real cell?
Not living
No organelles
No proteins
Cannot do active
transport (only
passive = diffusion)
Living
BOTH:
Have a
selectively
permeable
membrane
Can do
passive
transport
Has organelles
Has proteins
Does both active and
passive transport
Diffusion Through a Membrane
 What
lab?
indicators were used in the
Diffusion Through a Membrane
 What
lab?
indicators were used in the
IODINE was used to test
for the presence of
STARCH. Color changes
from amber to
blue/black.
BENEDICT’S SOLUTION
(blue) tests for
GLUCOSE. After
heating, it turns
orange if glucose is
present.
Diffusion Through a Membrane
 We
used test tubes with just water
and Benedict’s and another with just
water and iodine. Why?
Diffusion Through a Membrane
 We
used test tubes with just water
and Benedict’s and another with just
water and iodine. Why?
These two test tubes
served as negative
controls. This showed us
what a negative test
would look like.
Diffusion Through a Membrane
 We
also used test tubes with iodine
and starch, and another with
Bendict’s and glucose. Why?
Diffusion Through a Membrane
 We
also used test tubes with iodine
and starch, and another with
Bendict’s and glucose. Why?
These two test tubes
served as positive
controls. They showed
us what a positive test
for starch and glucose
looked like.
Diffusion Through a Membrane
 What
will happen in this experiment?
Diffusion Through a Membrane
 What
will happen in this experiment,
The iodine is small
and why?
enough to fit through
the membrane. It
diffuses into the “cell”
and turns the starch
inside a blue/black
color. The starch is
too large to diffuse
through the selectively
permeable membrane,
so it cannot diffuse out
into the surrounding
solution.
Diffusion Through a Membrane
 Glucose
is in the cell below. What
will happen, and how do you know?
Diffusion Through a Membrane
 Glucose
is in the cell below. What
will happen, and how do you know?
When we test the outside
solution for glucose using
Benedict’s (after heating it), the
solution turns orange. This
indicates that the glucose
diffused out of the cell into the
surrounding solution. The
glucose was small enough to fit
through the selectively
permeable membrane.
Diffusion Through a Membrane
 Osmosis
 Explain
the process that is occurring
in the diagram in the link.
Diffusion Through a Membrane
 Osmosis
 Explain
the process that is occurring
in the diagram in the link.
–The water molecules move from an
area of high concentration of water
(lower solute) to an area of lower
concentration of water (higher
solute).
Diffusion Through a Membrane
 Which
way will diffusion (osmosis)
occur? (Percents indicate
concentration of water.)
97%
99%
Diffusion Through a Membrane
 Which
way will diffusion (osmosis)
occur? (Percents indicate
concentration of water.)
97%
99%
Diffusion Through a Membrane
 Which
way will diffusion of water
(osmosis) occur? (Percents indicate
concentration of solute.)
3%
1%
Diffusion Through a Membrane
 Which
way will diffusion of water
(osmosis) occur? (Percents indicate
concentration of solute.)
3%
1%
Diffusion Through a Membrane
 What
is happening here?
Diffusion Through a Membrane
 What
is happening here?
When salt water is placed on cells,
the water diffuses out of the cells’
cytoplasm into the salt solution.
(Water moves from a higher
concentration – inside the cell – to
a lower concentration – outside
the cell.)
If fresh water is placed on the
cells again, the water will flow
back into the cells (high to low
concentration).
Diffusion Through a Membrane
 Why
didn’t the cell walls shrink with
the cytoplasm?
Diffusion Through a Membrane
 Why
didn’t the cell walls shrink with
the cytoplasm?
– Cell walls are rigid – they provide
support for plant cells.
Diffusion Through a Membrane
 Does
this organism live in fresh
water or salt water? Explain how
you can tell.
Diffusion Through a Membrane
 Does
this organism live in fresh
water or salt water? Explain how
you can tell. Fresh water: The organism contains a
contractile vacuole. Contractile
vacuoles serve to pump out excess
water from the interior of the cell.
If the organism needs to pump out
water, it must have a lower
concentration of water on its inside
than outside (water keeps diffusing
into it). This means that the water
outside has fewer solutes. The water
must be fresh.
Making Connections
 What
lab?
are the two purposes of this
Making
connections between
data and conclusions
Designing a controlled
experiment
Making Connections
 Why
is it more accurate to take two
or three pulse readings and average
them?
Making Connections
 Why
is it more accurate to take two
or three pulse readings and average
them?
Cancel
out errors
The data may vary – this makes
it more reliable
Making Connections
 Why
were the class results averaged
and used?
Making Connections
 Why
were the class results averaged
and used?
More trials means more accurate
data
More subjects means more
accurate data, too.
Making Connections
What
is muscle fatigue?
Making Connections
What
is muscle fatigue?
The “tiring” of the
muscles through
overexertion.
Making Connections
What
waste products cause
muscle fatigue?
Making Connections
What
waste products cause
muscle fatigue?
Mitochondria
ATP
O2 + glucose
CO2 + H2O
Capillary
Making Connections
What
waste products cause
muscle fatigue? CO2, Lactic
Mitochondria
Acid
ATP
Or, Lactic acid
O2 + glucose
CO2 + H2O
Capillary
Making Connections
 Why
does muscle fatigue happen?
Making Connections

Why does muscle fatigue happen?
 The
more the muscle is used, the more
waste products are produced. If the
blood isn’t circulating fast enough to
carry away the wastes, they build up.
As a result, the heart pumps faster and
breathing increases to circulate the
wastes out to the lungs faster. (This
also brings O2 and glucose to the cells
faster to be used for making ATP.)