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Living Environment Labs Review: Beaks, Biodiversity, Diffusion
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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.)
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