1st Semester 57 - BIOLOGY JUNCTION

Food Testing

Chemical Tests for Nutrients in Food

INTRODUCTION:

Cells are made up of small molecules like water; ions such as sodium and magnesium, and large organic molecules. There are four important types of large organic molecule in living organisms — proteins, carbohydrates (sugars & starches), lipids (fats), and nucleic acids. Proteins, carbohydrates, and fats serve as nutrients in the food that we eat.

In this experiment you will evaluate the nutrient content of unidentified food samples. You will use chemical reagents to test the unknown for specific nutrients. By comparing the color change a reagent produces in the unknown with the change it produces in the known nutrient, you can estimate the amount of that nutrient. Use small samples.

MATERIALS:

400-ml beaker
Hot plate
8 test tubes
Test tube rack
4 medicine droppers
Glass stirring rod
Tongs
Several unknown food substances
Glucose
Cornstarch
Non-fat dry milk
Lard
Distilled water
Benedict’s solution
Iodine-potassium iodide solution
10% aqueous sodium hydroxide solution
0.5% Copper sulfate solution
Sudan III solution

PROCEDURE:

Monosaccharide (simple sugar) test

1. Fill a 400-ml beaker to about 300 ml with water and heat on the hot plate.

Be sure to label all test tubes.

2. Place pea-sized portions of glucose and the unknown substance you are testing in separate test tubes. Add about 2.5 ml of distilled water and 10 drops of Benedict’s solution to each test tube. Mix with a stirring rod, or holding the tube between the thumb and index finger of one hand, thump it with the middle finger of the other hand to mix.

REMEMBER: If you use a stirring rod, wash it after every use, so you won’t contaminate one solution with another.

3. When the water boils, use tongs to place the test tubes in the water bath. Leave the test tubes in the water bath for 10 minutes.

Do not let the water bath boil hard. Control the boiling by turning the hot plate on and off as needed.

4. Remove the test tubes with tongs and place the tubes in a test tube rack. Unplug the hot plate to cool. When the tubes cool, an orange or red precipitate will form if large amounts of glucose are present. Small amounts of glucose will form a yellow or green precipitate. Record your observations in the DATA TABLE.

Polysaccharide complex sugar) test

5. Place cornstarch in a clean test tube and some of the unknown substance in another. Use a clean dropper to add 10 drops of iodine-potassium iodide solution to each test tube. Observe the results and record in the DATA TABLE.

Protein test

6. Place non-fat dry milk in a clean test tube and some of the unknown in another. With a clean dropper slowly add an amount of sodium hydroxide solution about equal to the amount of the milk sample, and mix carefully. Then add 10 drops of copper sulfate solution one drop at a time. Mix gently between drops. Observe the results and record in the DATA TABLE.

7. Repeat step 6 with the unknown substance.

Lipid test

8. Place a small piece of lard in a clean test tube and some of the unknown in another. Use a clean dropper to add 10 drops of Sudan III solution to each test tube. Mix well, observe and record your results in the DATA TABLE.

DATA TABLE:

Monosaccharide test		Polysaccharide test
Mark your results in the appropriate boxes. Indicate relative amount by H for high, M for medium, L for low, or 0 for none.
SUBSTANCE:	RELATIVE AMOUNT:	SUBSTANCE:	RELATIVE AMOUNT:
Unknown	Unknown
Glucose	Corn starch

Protein test		Lipid test
SUBSTANCE:	RELATIVE AMOUNT:	SUBSTANCE:	RELATIVE AMOUNT:
Unknown	Unknown
Non-fat dry milk	Lard

CONCLUSIONS:

Question 1 . What is the main nutrient in the unknown?

Question 2. What are the controls in this investigation?

Evolution & Phylogeny AP Study Guide

Unit 6 Evolution & Phylogeny Study Guide
Be able to give an example of an idea that Charles Darwin borrowed from Thomas Malthus Know some anatomical structures that would be homologous to the wing of a bat Know what important information was unavailable to Darwin in the mid-nineteenth century when he formulated his theory of evolution Know the name of Darwin’s 1859 publication Be able to explain all parts of the Darwin-Wallace theory of natural selection Be able to explain how phylogenetic relationships are determined for closely related species Be able to differentiate between analogous & homolgous structures Know the requirements for the maintenance of Hardy-Weinberg equilibrium Be able to use the Hardy-Weinberg equation to determine allele frequencies and genotypic frequencies Be able to describe and give an example of a cline Be able to explain the bottleneck effect Know what process creates new alleles and serves to balance natural selection Be able to explain & give an example of genetic drift Know what is meant by the “gene pool” Know the major divisions of geologic time Be able to give several examples of fossil types Be able to explain binomial nomenclature Be able to list in order the major taxonomic categories Know what individuals in a population would most often carry copies of harmful recessive alleles Be able to explain & give an example of hybrid sterility Be able to explain & give an example of ecological isolation of species Know what polyploidy is & how it can cause rapid speciation Know the effect of mitosis & meiosis on allelic frequencies in nature Be able to explain the effect on alleles when new members move into a population Know the difference in prezygotic & postzygotic barriers Be able to name & and give examples of prezygotic and postzygotic barriers Be able to explain & give examples of mechanical and behavioral isolation Know the difference between sympatric isolation and allopatric isolation Be able to explain why such a great diversity of life exists on the Hawaiian & Galapagos Islands Be able to tell the difference between anagenesis & cladogenesis Know what taxonomic level can exist as a discrete unit in nature Know what taxonomic unit would show the most genetic variation Be able to explain & give an example of adaptive radiation Be able to determine the age of a fossil using the half-life of carbon-14 Know what major evolutionary episode occurred closely with the formation of Pangaea Be able to explain phylogeny Know the significance of the asteroid hypothesis Be able to explain & give examples of divergent & convergent evolution

Evolution Answers

Evolution Answers

1. In biological terms, what is a species? a group of organisms that are similar in form and structure
  a group of organisms that can interbreed
  a group of organisms that share common features
  a group of organisms that have live in the same habitat
2. What is the Scala Naturae? an idea proposed by Darwin that suggests that all organisms share a common ancestor
  an idea proposed by Plato that suggests organisms are all evolving toward an ideal form
  an idea proposed by Aristotle that suggests that all organisms fit into an orderly scheme
  an idea proposed by Wallace that suggests that organisms change over time
3. Creationism is not accepted as a valid scientific theory because: it violates the scientific principle of natural causality
  it doesn’t offer a model to explain the diversity of life on earth
  it cannot be disproven
  all of these

birds

1. The picture of the finches is used to illustrate: phylogeny of finches
  change over time
  specialization of beaks for different diets
  natural selection
2. Which of the following was not an observation made by Darwin on his voyages: penguins use wings to paddle instead of fly
  snakes have rudimentary hind limbs
  the earth is very old
  islands had species that did not exist on the mainland

bones

1. The image illustrates: vestigial structures
  homologous structures
  the fossil record
  natural selection
2. Which of the following is an example of artificial selection: a panda’s thumb
  the breeding of dogs
  the galapagos finches
  a giraffe’s neck
3. According to the theory of evolution by natural selection, which of the following is true: random mating is necessary for evolution to occur
  variation does not exist between members of the same species
  populations will change to better fit their environment
  individuals will adapt to their environment
4. Which of the following are assumptions made with regards to the Theory of Evolution by Natural selection organisms compete with each other to survive
  variations exist among organisms
  not all organisms that are born survive to reproduce
  all of these

whale

1. The image illustrates which of the following: artificial selection
  acquired characteristics
  homologous structures
  vestigial structures
2. A panda’s thumb is considered an evolutionary contrivance because: it is assembled from wrist bones, and imperfect
  it is perfectly structured to grab leaves
  it is an structure that has no use
  none of these
3. Which of the following outcomes would you predict for a population of bacteria exposed to a new antibiotic. over many generations, the bacteria would become resistant to the antibiotic
  over a few generations, the bacteria would evolve into Archaebacteria
  over a few generations, the bacteria would become extinct
  over many generations, the bacteria would become more susceptible to the antibiotic
4. Which of the following is an example of convergent evolution: whales and sharks have similar body designs
  bees and hummingbirds have similar body designs
  bats and birds have similar body designs
  all of these
5. Why is evolution called the “unifying theory of biology” because it explains the diversity of life on the planet
  because it serves as a model to predict how organisms will change
  it serves as a model to interpret relationships between organisms on the planet
  all of these

moths

The image illustrates how peppered moths are related to other moths
how peppered moths adapted to a changing environment
how peppered moths became extinct
how peppered moths became two species

Evolution BI Worksheet

EVOLUTION

Section 14-1 Biogenesis

1. Define biogenesis.

2. What is spontaneous generation & give an example. Can spontaneous generation occur?

3. Describe Redi’s experiment and its results.

4. Describe Spallanzani’s experiment and its results.

5. Did Redi & Spallanzani’s experiments disprove spontaneous generation? Explain.

6. Describe Pasteur’s experiment and its results. Did it prove or disprove spontaneous generation?

Section 14-2 Earth’s History

7. What is the estimated age of the earth?

8. a. What is radioactive dating, and how is it used to tell the age of materials?

b. Use a science dictionary to look up and explain relative dating of fossils.

9. What is meant by half-life?

10. Name 3 radioactive isotopes and give their half-life.

11. a. What 2 scientists set up an experiment that simulated the atmosphere of early earth?

b. What molecules were made during this experiment?

Section 14-3 The First Life Forms

12. Why was there no oxygen in the early atmosphere?

13. Were the 1st cells probably aerobic or anaerobic? Why?

14. What gases did the early atmosphere contain primarily?

15. What bacteria live in harsh environments containing methane gas?

16. Oxygen didn’t become part of our atmosphere until what process started taking place?

Section 15-1 Fossil Record

17. What is a fossil?

18. In what type of rock are fossils usually found?

19. What is sedimentary rock?

20. From what part or parts of organisms do sedimentary fossils usually form?

21. How do sedimentary fossils form?

22. How do casts form?

23. What do you call imprint fossils?

24. Complete insect fossils can be found inside of a clear, golden material called ________________.
25. Who was one of the first scientists to study fossils?

26. In which rock layer or strata would the oldest fossils be found? The newest fossils?

27. Name the 4 eras of earth’s history in order beginning with the oldest & going to present day.

28. Which organisms appeared first in earth’s history?

29. Name the period in which each of these events occurred:
a. Humans appeared?
b. Mass extinction of dinosaurs?
c. Land plants appeared?
d. Birds appeared?
e. Fish appeared?
f. Reptiles appeared?
g. Modern mammals appeared?

30. What is true about fossils in the same rock layer or strata?

31. a. What is meant by mass extinction and give an example?

b. Has there been more than one mass extinction in earth’s history? Explain.

32. Radioactive isotopes are used to determine the ___________________ age of fossils.

Section 15-2 Theories of Evolution

33. What was Lamarck’s hypothesis about how species change?

34. What is meant by acquired trait?

35. What did Lamarck think had caused the webbed feet of water birds?

36. How did Lamarck think the offspring of these web-footed birds got their web-feet?

37. Can traits be passed in this way? Explain why or why not.

38. Was Lamarck’s idea of acquired traits proven or rejected?

39. Charles Darwin’s idea of how species change over time is called what?

40. Explain natural selection.

41. What other scientist came up with this same idea about evolution?

42. What was the name of the book that Darwin published with his ideas about evolution?

43. Explain how Darwin obtained all of his records & supporting evidence that led him to his theory of natural selection.

44. Describe the voyage of the H.M.S. Beagle.

45. What book did Darwin read that influenced his ideas when he sailed on the Beagle? Who was the author?

46. What unusual information did Darwin collect about the Galapagos finches on his voyage?

47. What forced Darwin to move ahead and publish his ideas?

48. State the 2 theories that sum up Darwin’s ideas about evolution & natural selection.

49. State Darwin’s Descent with Modification theory.

50. Darwin’s theory stated that all the Galapagos finches had descended from what?

51. State Darwin’s Modification by Natural Selection theory.

52. What idea, published in a book by Thomas Malthus, did Charles Darwin use?

53. According to Darwin, what limits the growth of populations?

54. How do populations of organisms adapt to their environment?

55. What is meant by the fitness of an organism?

Section 15-3 Evolution in Process

56. What are homologous structures and give an example?

57. What are analogous structures & give an example?

58. Which structures, homologous or analogous, show that organisms are more closely related?

59. What are vestigial structures & give an example?

60. Vestigial structures show __________________________ ancestry.

61. In the early stages, how do all vertebrate embryos compare with each other? What does this indicate?

62. Organisms with homologous (similar) _________________ & __________________ acids are probably more closely related.
63. What is co-evolution & give 2 examples of organisms that co-evolve?

64. Are a shark and a porpoise closely related? Explain your answer.

65. When does convergent evolution occur?

66. What is divergent evolution?

67. Divergent evolution usually results in new ________________________.

68. What is adaptive radiation & give an example?

69. How can adaptive radiation be sped up & give an example?

Section 16-1 Genetic Equilibrium

70. Do populations change quickly or slowly?

71. What is the study of evolution using genetics called?

72. Do individuals evolve?

73. Do populations evolve?

74. Variations in traits may be due to ___________________ factors or __________________.
75. Name the 3 ways variations in genotypes arise.

76. What is meant by the gene pool?

77. How many alleles exist for each trait in a gene pool?

78. How is allele frequency determined?

79. Determine the frequency of each allele in the following genotypes:
a. AA?
b. Aa?
c. aa?

80. How is phenotypic ratio determined?

81. What is the phenotypic frequency of white, pink, & red four-o-clocks in these crosses?
a. RR x rr ?
b. Rr x Rr ?
c. Rr x rr ?

82. The frequency of alleles or phenotypes in a cross must always add up to ______________.

83. What does the Hardy-Weinberg theory state about allele frequencies in a population?

84. List the 5 conditions that must hold true in the ideal population for Hardy-Weinberg to be correct.

85. Would the Hardy-Weinberg law apply to real populations?

Section 16-2 Disruption of Genetic Equilibrium
86. What effect does evolution have on a population’s genetic material?

87. Does evolution affect allele frequencies?
88. Any violations of the 5 conditions necessary for Hardy-Weinberg can result in _____________.

89. A change in genetic material is known as a _______________________.

90. Mutations occur constantly at _______________ rates unless an organism is exposed to ___________.

91. Most mutations are __________________, but some may be _____________________ & help the population evolve & survive.
92. Compare & contrast population immigration & emigration.

93. What is gene flow & give an example?

94. Does the Hardy-Weinberg law apply to small and medium sized populations?

95. What is genetic drift?

96. In what size populations does genetic drift apply & explain why?

97. Do all populations mate randomly? Explain.

98. What is the effect of matings of related individuals?

99. What is the most significant factor that affects genetic equilibrium?

100. Name the 4 types of natural selection & explain each.

101. Give an example of stabilizing selection using body size of lizards.

102. Give an example of directional selection using tongue length of anteaters.

103. Give an example of disruptive selection using limpets.

104. Explain the following — “genes of successful reproducers, rather than those of successful survivors, are amplified through natural selection.”

Section 16-3 Formation of Species

105. Do new species ever form? Do old species ever disappear? Explain your answer.

106. Define speciation.

107. Are all new species similar to their ancestral species? Explain.

108. What did scientists use for many years to help classify organisms?

109. What is morphology?

110. What are some limitations of using only morphology to identify organisms?

111. What is the biological species concept?

112. Does this concept help identify extinct species & why?

113. Members of a species are _________________similar & can __________________ to produce _____________________ offspring.
114. What does speciation begin with & does it affect mating?

115. Name 2 important types of isolation.

116. Define geographic isolation.

117. Give an example of how this type of isolation could occur.

118. What happens to the 2 subgroups after being geographically isolated from each other?

119. Define reproductive isolation.

120. Name & describe the 2 types of reproductive isolations.

121. Not recognizing mating calls or having different breeding times are examples of what type of isolation?

122. An infertile mule produced when a donkey and a horse mate is an example of ______________________ isolation.
123. Speciation often requires ______________________ of years.
124. Can some species form more quickly than others? Explain.

125. Does fossil record support a slow, gradual or more “instant” change in species?

126. A more “instant” formation or change occurs in ___________________, not millions of years.
127. What is this type of quicker species formation called?

128. What does punctuated equilibrium mean?

BACK

Evolution Myths

Myths About Evolution

Myth	Debunked
1. Charles Darwin developed the theory of evolution	The theory of evolution existed before Darwin, it was Darwin’s Theory of Evolution by Natural Selection that became widely accepted.
2. Living things adapt to their environment	As a whole, living things are adapted to their environment. Individuals are unchanging, they either live or die based on the traits they are born with.
3. Biologists “believe” in evolution.	Science is not based on belief. The theory of evolution provides a model for scientists to understand the relationships between organisms on the planet.
4. Monkeys will eventually become human.	There are many species of primates and all are adapted to their environment. A chimpanzee would not turn into a human over time anymore than a cheetah would turn into a lion (or vice versa)
5. Evolution is JUST a theory.	Saying that it is “just” a theory implies that it is a guess, or that its not well supported. There is much evidence to support the theory of evolution, as well as direct observation of species change.
6. Only atheists accept the Theory of Evolution.	Scientists of many religions across the world accept evolution, and do not find it incompatible with their faith.
7. If evolution is disproven, creationism must be true.	A problem with logic (disconfirming evidence). Even if you disproved evolution, you would have to develop and support another model of organism diversity. Disproving one, doesn’t prove the other.
8. No one has ever seen evolution happen.	In organisms that reproduce quickly (like bacteria) changes in species can be directly observed, such as resistances to antibiotics.
9. Order cannot come from disorder, so evolution is false.	Many instances in nature show molecules and substance organizing, such requires energy. The sun provides the energy that ultimately fuels all of life’s processes.
10. There is evidence that dinosaurs lived with humans	There is no evidence that suggests humans and dinosaurs lived at the same time.
11. Scientists regularly debate that evolution occurs.	Scientists debate elements of evolution, relationships between organisms, and fossils. The only place the evolution debate really happens is in the social settings.
12. Creationism is a valid scientific theory and should be presented with evolution.	Creationism violates the scientific principle of natural causality.
13. There are no transition fossils.	Museums are filled with fossils that show intermediate species.
14. Carbon dating is not accurate, therefore the age of the earth cannot be determined.	Carbon dating is one of many methods used to date the earth. Taken as a whole, the evidence is overwhelming that the earth is very old.