28 - South Side High School
28
MENSTRUAL CYCLE
NAME: ___________________________________
TEACHER: _______________________________
PERIOD: _________________________________
DATE: ___________________________________
DATE DUE: _______________________________
NAME: __________________________ DATE: ___________________
LAB #28 DUE DATE: ____________ MENSTRUAL CYCLE
When a human female is born, her ovaries already contain all the primary egg cells that will mature and produce eggs during her lifetime. Oogenesis generally begins between the ages of 12 and 14, when the female reaches sexual maturity. Most commonly, eggs mature every 28 days or so, usually at one time, in alternating ovaries. The rhythmic maturation of eggs and the events that accompany the process are termed the menstrual cycle.
Each egg matures inside an egg sac, or follicle, near the surface of one of the ovaries. When the egg is fully mature, this follicle bursts. The egg is released in a process called ovulation. Cilia sweep the egg into the oviduct, which leads to the uterus. An unfertilized egg will pass from the female’s body within a short time. The lining of the uterus, which had been prepared for the arrival of an embryo, deteriorates and also passes out of the body. This periodic loss of tissues and fluids from the uterus is a normal function known as menstruation. A menstrual cycle is considered to begin at the onset of menstruation.
Hormones carried in the bloodstream bring about the changes in the menstrual cycle by means of “negative feedback”. The pituitary gland below the brain secretes hormones that signals the growths and secretions in the ovary. Later, when the ovarian secretions reach low levels, these low levels stimulate the pituitary gland to secrete more hormones, which stimulate the development of another egg.
The objective of this investigation is to:
1) construct and interpret graphs which show hormone concentrations and the size of cells in the uterine lining during the menstrual cycle.
MATERIALS - colored pencils
PROCEDURE
PART A - Days 1 - 14
1) Observe the set of graphs in the analysis. Notice that B and D show events that occur
during the menstrual cycle. A and C are graphs, which you will complete, that show
levels of hormones that are secreted during the menstrual cycle. Note that each
graph has two different y-axes (right side and left side) to be used for plotting
different hormones.
Inside a follicle of an ovary is a single maturing egg or ovum. On day 1 of a cycle, the follicle of a new egg is about to be stimulated to grow by an increase in the amount of follicle-stimulating hormone (FSH) in the blood. FSH is secreted in the pituitary gland.
2) Use the data from the Table 1 (days 1-14) on the top of the following page, and a
colored pencil to plot points on Analysis graph A to indicate the concentrations of
FSH in the blood. Make sure to use the vertical axis on the left side.
3) Check the points, then use a pencil to draw a smooth curve through the plotted points.
3) Answer questions 1 and 2 on the attached question sheet based on Analysis graphs A and B and your knowledge of the menstrual cycle.
The growing follicle secrete estrogen in increasing amounts. By the 13th day, the concentration of estrogen has increased to the point that it causes FSH secretion to decrease.
5) Use the data from the Table 1 (days 1-14) and a colored pencil to plot points in
Analysis graph C to indicate the concentration of estrogen in the blood. Make sure to
use the vertical axis on the left side.
6) Check the points and draw a smooth curve as you did for FSH in step 3.
The increased estrogen in the blood stimulates the cells of the uterus to form new tissue containing capillaries. In this way, the uterus is prepared for the arrival of an embryo.
7) Look at analysis graph D. Notice that during menstruation, the lining of the uterus
deteriorates. Between days 5 and 15, the lining reforms. Based on this information,
answer question 3 on the attached sheet.
The increased concentration of estrogen that occurs also stimulates the secretion of luteinizing hormone (LH), another pituitary hormone. By day 14 or 15, ovulation has occurred and LH is at its highest concentration.
8) On Analysis graph A, use table 1 to plot the points indicating the concentrations of
LH from FSH. Make sure to start plotting on the left side, yet plot progesterone
points based on the right-hand vertical axis.
9) Check the points and draw a smooth curve.
9) Answer question 4 on the attached sheet.
10) On Analysis graph C, use table 1 to plot the points indicating the concentrations of progesterone for days 1-14. Use a different color to distinguish it from estrogen. Make sure to start plotting on the left side, yet plot progesterone points based on the right-hand vertical axis.
PART B - Days 15 - 25
After ovulation, the ruptured follicle that remains in the ovary is stimulated by LH to become the corpus lutus (“yellow body). The corpus luteum acts as an endocrine gland,
secreting progesterone. Progesterone stimulates the uterus to maintain its thickened lining.
1) Find the 15th day in Analysis graph B. Note the changes in the follicles tissue
between days 15 and 28.
By the time ovulation has occurred, the secretion of estrogen by the follicle has stopped. The decrease in estrogen causes the production of LH to decrease. Thus the corpus luteum degenerates and stops producing progesterone.
2) In Analysis graph C, plot points indicating concentrations of estrogen on days
15-28. See table 2 for data. Draw the remainder of the curve for estrogen in the
same color. Label the curve.
3) In analysis graph A, plot data from table 2 to show concentrations of LH on days
15-28. Draw the remainder of the curve and label.
4) In Analysis graph C, plot data from table 2 to show concentrations of progesterone
for days 15-28. Draw the remainder of the curve and label.
If fertilization occurs and an embryo is implanted in the uterine wall, additional hormones will maintain the uterine lining throughout the pregnancy. If no fertilization occurs, the concentration of progesterone in the blood decreases rapidly. By day 28, the concentrations of both estrogen and progesterone are at their lowest levels. This condition signals the onset of menstruation - the end of the current cycle and the beginning of the next.
Since the secretion of FSH is also triggered by simultaneously low concentrations of estrogen and progesterone, a new follicle will be stimulated to develop only when concentrations of estrogen and progesterone are low.
5) In Analysis graph A, plot data from table 2 to show concentrations of FSH on days
15-28. Draw the remainder of the curve and label.
6) Answer questions 5 through 9 on the attached sheet.
[pic]
[pic]
QUESTION SHEET
1) On what day does FSH reach maximum concentration in the blood?
2) What happens to the follicle during the first 14 days of the cycle? What causes these
changes?
3) What happens in the ovary (graph B) and in the bloodstream (graph C) that brings
about the change in the uterus (graph D) from days 5-15?
4) a) On what day of the cycle does LH reach maximum concentration in the blood?
b) What significant event of the cycle occurs almost immediately after LH reaches its
peak?
5) What would happen if progesterone levels did not increase sharply during the corpus
luteum stage of the cycle?
6) Why does the level of FSH decrease and remain at a relatively low level through days
15-28?
7) What process signals the end of one cycle and the beginning of the next?
8) Describe, in detail, a negative feedback mechanism that operates during the
menstrual cycle to regulate the concentrations of any two hormones. Remember that
negative feedback helps to keep hormone concentrations in the bloodstream within
their “normal” ranges.
9) X-TRA CREDIT! This lab neatly displays what occurs during the menstrual cycle if an egg is not fertilized. The extra layers of uterine lining are passed out in menstrual flow. In terms of specific glands and hormones, explain what would occur differently if the egg is fertilized and the uterine lining maintained.
29
HOW DOES A HUMAN FETUS CHANGE DURING DEVELOPMENT?
NAME: ______________________________________
TEACHER: ___________________________________
PERIOD: _____________________________________
DATE: ______________________________________
DUE DATE: __________________________________
NAME: ___________________________ DATE: ______________________
HOW DOES A HUMAN FETUS CHANGE DURING DEVELOPMENT?
LAB # _29_
GOALS: In this activity you will:
• measure the length of diagrams of the human fetus.
• graph the length and mass of a human fetus.
• determine when during development most changes in mass and size occur.
KEYWORDS: Define the following keywords:
development ______________________________________________________________
embryo ___________________________________________________________________
fetus _____________________________________________________________________
mass _____________________________________________________________________
premature ________________________________________________________________
MATERIALS: metric ruler
PROCEDURE:
PART A: Development of a Human Fetus
1. Look at Figure 1. It shows six stages of a developing human fetus. They are shown at 40% of their natural size.
2. Follow the steps outlined below to measure the total length of each stage. Use the metric ruler and measure in millimeters. Use the 38-week stage as a guide and record your data in the spaces provided in Table 1.
a. Measure the body length from the rump to the top of the head.
b. Measure the thigh length from the rump to the knee.
c. Measure the length of the leg from the knee to the foot.
3. Add all three measurements together and record the total in the space provided in Table 1.
4. Multiply the total by 2.5 to give a figure that is close to the actual size of the fetus at each stage.
5. Record this actual size in the table.
[pic]
|Age of |Body + |Thigh + |Leg = |Total x 2.5 |= Actual |
|Fetus |Length |Length |Length |Length |Length |
|2 | | | | | |
|9 | | | | | |
|16 | | | | | |
|20 | | | | | |
|24 | | | | | |
|32 | | | | | |
|38 | | | | | |
PART B: Plotting Length of a Developing Fetus
1. Plot the data from Table 1 onto the graph in Figure 2.
2. Plot the actual fetal length against the age of the fetus. Notice that the length of the fetus at week 2 has already been plotted.
[pic]
PART C: Plotting Mass of a Developing Fetus
1. Look at the data supplied in Table 2.
2. Plot the data of the developing fetus from Table 2 onto the graph in Figure 3.
3. Plot the mass of the fetus against the age of the fetus.
Table 2: Mass of a Developing Fetus
[pic]
QUESTIONS:
1. During what weeks of development is the human baby called an embryo?
____________________________________________________________________
2. What is the length of an embryo during this time? _________________________
3. How much mass does an embryo gain during this time? _____________________
4. During what weeks of development is the human baby called a fetus? ________
____________________________________________________________________
5. Look at Figures 2 and 3 for the halfway point in development at week 19.
a. Is the fetus half of its full length at this time? __________________________
b. Is the fetus half of its full mass at this time? __________________________
6. a. At what week does the fetus reach half its full length? __________________
b. At what week does the fetus reach half its full mass? ___________________
1. If a premature baby is born with a mass of
a. 2200 grams, how old is the fetus? ____________________________________
b. 1800 grams, how old is the fetus? ____________________________________
30
FLOWER DISSECTION
NAME: ______________________________________
TEACHER: ___________________________________
PERIOD: _____________________________________
DATE: ______________________________________
DUE DATE: __________________________________
NAME: ___________________________ DATE: ______________________
FLOWER DISSECTION
LAB # _30
PURPOSE: To study the structure of a large flower and to examine how that structure is well adapted to its reproductive role.
MATERIALS: gladiolas or amaryllis; dissecting trays; glass slides; microscope; scalpel; video microscope
PROCEDURE:
1. Examine your flower. Count the number of petals, stamens, and stigmas and record below.
petals ____________ stamens _____________ stigmas ______________
2. Carefully remove one of the stamens and brush some pollen grains from its anther onto a clean, dry slide. DO NOT cover the pollen grains with a coverslip. Examine the pollen under LOW power of your microscope and prepare a drawing of the pollen grains on a separate sheet of paper.
3. Carefully remove the petals from your flower and locate the ovary of your flower’s pistil. Cut open the ovary with the scalpel and locate the ovules. These are NOT seeds. The ovules contain unfertilized egg cells and will develop into seeds once the egg cells are fertilized.
4. Prepare your own diagram of a typical flower (try sketching the flower you had in class) and label the following structures:
sepals, petals, anthers, filaments, stigma, style, ovary
NAME: ___________________________ DATE: ______________________
LAB # _30_
SKILL PRACTICE
1. Which of the following factors would least benefit plant growth rate?
a. warm temperature
b. high levels of sulfur dioxide
c. moderate moisture level
d. sufficient sunshine
2. A sweet smelling, brightly colored flower would most likely be pollinated by
a. wind
b. water
c. insects
d. diffusion
3. Which function must happen before fertilization in flowering plants can occur:
a. ovulation
b. pollination
c. grafting
d. seed disposal
4. For what type of reproduction is the flower adapted?
a. sexual
b. budding
c. asexual
d. runners
5. On which structure shown in the diagram at the right, must
pollen land before fertilization can take place?
a. A
b. B
c. C
d. D
6. A fruit develops from the
a. leaf
b. flower
c. root
d. stem
Directions: (7-9): Base your answers to questions 7 through 9 on the diagram at the right that represents a flower and on your knowledge of biology.
[pic]
7. Which part of the flower will become the fruit?
a. 1
b. 2
c. 5
d. 4
8. The part of the flower that will become the seed is?
a. 1
b. 2
c. 3
d. 5
9. The part of the flower that produces the pollen grains is?
a. 1
b. 2
c. 3
d. 4
10. Which of the following is not needed to start the growth of a bean seed?
a. light
b. oxygen
c. proper temperature
PART A: Base your answers to questions 11 through 14 on the diagram of a flower below and on your knowledge of biology.
[pic]
11.Which structure produces cells that form sperm muscle?
a. 1
b. 2
c. 3
d. 4
12.In which structure do fertilization and development occur?
a. 1
b. 6
c. 3
d. 4
13.Which structures are collectively know as pistil?
a. 1 and 2
b. 2, 4, and 6
c. 1 and 6
d. 3, 4, and 5
14. In the space provided, place the names of the structures in the above diagram that correspond to each of the following numbers.
1 ________________________ 4 ________________________
2 ________________________ 5 ________________________
3 ________________________ 6 ________________________
Base your answers to questions 15 and 16 on the diagram below and on your knowledge of biology.
[pic]
15.Which structures form the stamen?
a. A and F
b. B and H
c. C and D
d. E and G
16.During pollination, pollen is transferred from
a. B to A
b. C to D
c. B to G
d. F to H
17. In which region of the flower represented below do diploid cells change to monoploid male gametes?
a. A
b. B
c. C
d. D
31
GENETICS: MAKING YOUR OWN CHILD
NAME: ______________________________________
TEACHER: ___________________________________
PERIOD: _____________________________________
DATE: ______________________________________
DUE DATE: __________________________________
NAME: ___________________________ DATE: ______________________
HAVING A CHILD OF YOUR OWN IN JUST ONE SCIENCE CLASS
LAB # _31_
INTRODUCTION: The Austrian monk, Gregor Mendel, determined the basic laws of genetics, the rules governing how traits are handed down from parent to offspring. A trait is passed down through genes, the basic unit of genetic information, with at least two genes, one from each parent, controlling its inheritance. Some traits are dominant, that is they prevent other traits from appearing. Some are recessive, these do not appear when a dominant gene is present.
For example, let us say that “tallness” is a dominant trait, and “shortness” recessive. The following diagram, called a Punnett Square, show what might happen when a plant with two tall genes (a pure tall) is crossed with a plant with two short genes (a pure short).
| |T pure tall T |
|s |Ts |Ts |
|pure short | | |
|s | | |
| |Ts |Ts |
T = tall
s = short
All the offspring would be hybrids, that is contain both a dominant and a recessive gene. Since we have determined that tallness is dominant, all offspring would look tall. But if we crossed these hybrids, we could get more varied results in the third generation as the following Punnett Square shows.
| |T hybrid s |
|T |TT |Ts |
|hybrid | | |
|s | | |
| |Ts |ss |
T = tall
s = short
It is important to note that the diagram holds true only when large numbers of offspring are represented. In this demonstration, we are going to discover what an offspring might look like if each parent is a hybrid for each characteristic and examine the possible variation that may result.
PROCEDURE:
1. You and your partner will be the father and mother of your offspring. In each coin toss, HEADS will stand for the DOMINANT gene and TAILS will represent the recessive gene.
2. Select an appropriate name for your child.
3. Flip the coin to determine the sex of your child. Since the father determines the sex of the offspring, only the father will flip the coin. HEADS is a boy; TAILS is a girl.
4. Use the coin to determine the genetic makeup of your child. Place your data in the data table. Use an upper case letter for a dominant toss and a lower case letter for a recessive toss. Each characteristic requires two separate coin tosses.
5. Note that Hair Color and Eye Color require four (4) coin tosses each.
6. Circle the appropriate phenotype for each characteristic. The “Checklist for Phenotypes” is provided for your convenience.
7. Describe your child in 100 words or less.
8. ** Show what your child will look like. You may do this by:
a. A drawing in any medium (one sheet only)
b. Tracing facial parts on a paper
c. Copying all face parts using those appropriate parts.
Hair color: Dark hair is dominant over light. To determine the color of the offspring’s hair, assume there are two gene pairs involved. There are probably more. Flip your coin first to determine the genotype of the first pair of genes: (AA, Aa, aa). Now flip your coins again to determine the genotype of the second pair of the alleles (BB, Bb, bb). Then match the genotype with the corresponding hair color by looking at the following chart.
If the genotype is:
AABB
AABb
AAbb
AaBB
AaBb
Aabb
aaBB
aaBb
aabb
Then the hair color is:
black
black
red
brown
regular blonde
brown
dark blonde
regular blonde
pale yellow blonde
[pic]
Eye color: Dark eyes are dominant over light. To determine the color of the offspring’s eyes, assume there are two gene pairs involved, one which codes for depositing pigment in the front of the iris, and one which codes for depositing pigment in the back of the iris. Determine the genotype of the first pair (AA, Aa, aa). Then flip again to determine the second pair of genes (BB, Bb, bb).
If the genotype is:
AABB
AABb
AAbb
AaBB
AaBb
Aabb
aaBB
aaBb
aabb
Then the eye color is:
dark brown
dark brown
brown
brown/green fleck
brown
gray-blue
green
dark blue
light blue (haze)
[pic]
[pic]
Checklist for Phenotypes—circle your coin flip results
Sex
Male
Female
Face shape
round
square
Chin shape (1)
very prominent
less prominent
Chin shape (2)
round
square
Cleft chin
absent
present
Eye shape
round
almond
Eye position
horizontal
upward slant
Eye color
dark brown
brown
green
brown/green flecks
gray blue
dark blue
light blue
Eyelashes
long
short
Freckles
present
absent
Hair texture
curly
wavy
straight
Widow’s peak
present
absent
Hair color
black
brown
red
blonde
dark blonde
pale blonde
Eyebrows (1)
bushy
fine
Mouth
long
average
small
Lips
thick
thin
Hapsburg lip
very protruding
slightly protruding
absent
Dimples
present
absent
Nose
big
medium
small
Eyebrows (2)
not connected
connected
Color of eyebrows
darker than hair
same as hair
lighter than hair
Eye distance
close together
average
far apart
Eye size
large
medium
small
Nose shape
rounded
pointed
Nostril shape
rounded
flared
Ear and Nose size
large ear/wide nose
small ear/narrow nose
Earlobes
free
attached
Darwin’s ear point
present
absent
Hairy ears (males only)
present
absent
[pic]
DISCUSSION:
1. Compare the image of your child to the children of the rest of the class. How much variation is there in this group?
2. If you plan to have your second child, how will the picture of your first child compare to your second child?
3. Why are hair color and eye color different from the other genetic characteristics?
4. What is incomplete dominance? Which traits of your child are incomplete dominance?
5. Nose tip thickness and size of ears are almost always inherited together. What does this suggest about the gene for nose tip thickness and the gene for ear size?
32
BIOMES
NAME:____________________________________
TEACHER: ________________________________
PERIOD: __________________________________
DATE: ____________________________________
DATE DUE: _______________________________
NAME: _______________________________ DATE: ______________
LAB# 32 WORLD BIOMES
Purpose: - To study where the various biomes are located in the world.
Materials: - world map
world biomes
Procedure:
1. Consult a textbook which shows the location of the various terrestrial world biomes.
2. On the attached world map, draw in those biomes, using a different color for each one.
3. On the bottom of the map, include a key indicating which color represents which biome.
Observations: Your completed world map, colored and keyed.
BIOMES. The biosphere is organized into small parts known as biomes. A biome is a large geographic area of the earth identified by a particular type of dominant (most common) plant and animal life. Biomes may be terrestrial (land) or aquatic (water). This is determined by geography and climate (Figure 28-2). The major land biomes are the tundra, taiga, temperate deciduous forest, tropical rain forest, grassland and desert biomes. The water biomes are the marine (saltwater) and freshwater biomes.
[pic]
CHARACTERISTICS OF MAJOR LAND BIOMES
Skill Practice
Part A. Base your answers to questions 1 through 5 on the diagrams below that represent different land biomes and your knowledge of biology.
[pic]
1. The biome represented by diagram D is known as a
1) desert (3) taiga
2) temperate and deciduous forest (4) tundra
2. Which of the biomes represented is located at the highest altitudes and/or the highest
latitudes?
1) A (3) C
2) B (4) D
3. Which biome has the greatest annual rainfall?
1) A (3) C
2) B (4) D
4. Daily changes in temperature would be greatest in the biome represented in diagram
1) A (3) C
2) B (4) D
5. Name the biome in the above diagram that is represented by each of the following letters.
A __________________________________________________________
B __________________________________________________________
C __________________________________________________________
D __________________________________________________________
[pic]
Part B. Base your answers to questions 1 through 4 on the diagram below and on your knowledge of biology. The diagram shows areas on a mountain that represent some major biomes.
[pic]
1. In which biome do lichens and mosses grow in large numbers and represent the
dominant plant life?
1) tundra (3) temperate deciduous forest
1) taiga (4) tropical rain forest
2. The characteristic climax vegetation of which biome consists of coniferous (pine) trees?
1) tundra (3) temperate deciduous forest
1) taiga (4) tropical rain forest
3. Which major biome is found throughout most of New York State?
1) tundra (3) temperate deciduous forest
1) taiga (4) tropical rain forest
4. Which diagram below best shows the order of major land biomes that would be met by a person who travels north from the Equator to the polar region at a steady elevation? _______________________
[pic]
Skill Practice
DIRECTIONS: Circle the number of the expression that best completes each of the following statements.
1. The primary source of energy for life on earth is
1) wood (3) oil
1) sunlight (4) coal
2. Which are classified as producers?
1) snakes and frogs (3) bacteria and molds
1) dogs and wolves (4) geraniums and algae
3. Decomposers are unable to break down
1) leaves (3) wood
2) plastic (4) cotton
Directions (4-7): Base your answers to questions 4-7
on your knowledge of biology and on the diagram
of an aquarium containing water, soil, green plants,
a snail and a fish.
4. Which gas do the snail and fish release into the water?
1) oxygen (3) carbon dioxide
2) nitrogen (4) hydrogen
5. The fish in the aquarium functions as a
1) producer (3) decomposer
2) consumer (4) parasite
6. The gas released by the green plants is used by the snail for
1) photosynthesis (3) excretion
2) digestion (4) respiration
7. Which organism supplies oxygen to the others?
1) snail (3) algae
2) fish (4) protozoa
Directions (8-10): Base your answers to questions 8-10 on the information below and on your knowledge of biology.
A large bottle with a layer of mud on the bottom
is filled with pond water. Several fish and some
green plants are then added and the bottle is
made airtight.
8. The living and nonliving contents of this bottle make up
1) an ecosystem (3) a biome
2) a population (4) a species
9. The green plants in this bottle are necessary as
1) producers (3) saprophytes
2) herbivores (4) consumers
10. When a fish in this bottle dies, the nitrogen from its body is released through the
action of
1) decomposers (3) algae
2) producers (4) viruses
33
ACID RAIN AND LOCAL ENVIRONMENTS
NAME: __________________________________
TEACHER: ______________________________
PERIOD: ________________________________
DATE: __________________________________
DUE DATE: _____________________________
NAME: _______________________________ DATE: ______________________
LAB # 33
Acid Rain in Local Environments
( ( ( ( ( (
The degree to which acid rain is destructive differs in the United States from region to region. Many factors influence the probability and the potential damage of acid rain.
Most experts agree the problem begins with the burning of coal, oil and natural gas.
Smokestacks as tall as 300 meters allow winds to carry pollutants far from local sources.
In addition, the capacity of the soil or bedrock to buffer the effects of acid rain varies. Limestone bedrock neutralizes the acid very well, whereas granite bedrock has no neutralizing effect at all.
You can study the extent of acid rain in your own area by starting with a map of the United States that displays several areas of greatest vulnerability. After determining the
degree of vulnerability, you can perform actual tests of your surroundings using the
LEAP- System™ BSCS Biology Lab Pac 2 includes instructions for use of the system.
Materials (per team of 4)
4 pairs of safety goggles forceps (optional)
4 lab aprons 8 pieces of filter paper
2 100-mL beakers 400 mL of acidic distilled water-pH4
100-mL graduated cylinder 400 mL of boiled distilled water-pH7
glass or plastic funnel individual students samples of:
pH probe rainwater
Apple lle, Apple IIGS, Macintosh, or soil
IBM computer lake or pond water
pH meter or wide range pH paper (optional) snow (if possible)
LEAP- System™
Procedure
1. Examine the map in Figure 22.1. According to the map, which part of the United
States are most susceptible to acid rain? According to the map, is acid rain
currently destructive to your area? What causes one area of the country to be more
susceptible to acid rain than another area?
1. In your data book, prepare a table in which to record your data.
2. Determine the pH of your rainwater sample by using a pH probe with the LEAP-System™, a pH meter, or by dipping small strips of pH paper held with forceps into the sample and comparing the color change to a standard color chart. Record the pH in your data table.
3. Place filter paper in a funnel and fill the funnel with soil from your sample.
4. Hold the end of the funnel over a small beaker and pour 100mL of boiled distilled water (pH7) through the soil. Dirty water should collect in the beaker.
5. Determine and record the pH of the collected water.
6. Repeat Steps 4 through 6 with a fresh soil sample, but this time pour 100mL of acidic distilled water (pH4) through the soil sample.
7. Determine and record the pH of your pond or lake water sample.
8. Melt your snow in a small beaker.
9. Determine and record the pH of the meltwater.
10. Wash your hands thoroughly before leaving the laboratory.
[pic]
Discussion
1. Compare the pH of your rainwater sample to that of normal rainwater (pH 5.6) and to
that of classmates who live in different neighborhoods. What are the differences in
pH? What might cause the differences?
2. What factors might cause a rainwater sample to be highly acidic?
2. How does the pH of your soil sample compare to that of your classmates? Give two
reasons why the pH of soil samples might differ.
3. Consider the class data on the pH of the rainwater of your area. In what way, if any,
is this rainwater affecting the acidity of your soil?
4. What is the pH of the acidic distilled water after it has passed through the soil and
collected in the beaker? Based on this data, discuss the buffering capacity of your
soil.
6. What might cause a soil to have a buffering capacity?
7. Considering the pH of your rainwater, could your soil be healthy without a buffering
capacity?
8. Compare the pH of your pond or lake water sample to that of healthy pond or lake water (pH around 6.5) and to that of classmates who have samples from different lakes or ponds.
9. If the pond or lake water is not too acidic and the rainwater is known to be acidic, what might be some factors influencing the acidity of the pond or lake water?
10. Consider the characteristics of the area around the pond or lake (for example, forest, farmland, bedrock). How might these factors influence the acidity of pond or lake water?
11. Compare the pH of your meltwater with that of your rainwater sample. Why might snow meltwater be more or less acidic than rainwater?
11. From your data, what time of year would you expect your lakes and soil to be most acidic? Explain.
34
EXPLORING A SOIL COMMUNITY
NAME: ______________________________________
TEACHER: ___________________________________
PERIOD: _____________________________________
DATE: ______________________________________
DUE DATE: __________________________________
NAME: _________________________ DATE: _____________________
EXPLORING A SOIL COMMUNITY
LAB # _33
OBJECTIVES: In this investigation you will:
• observe a soil community
• measure the total mass present at each trophic level in the community
MATERIALS: metric ruler; plastic bags; rubber bands; hand trowel; freezer; pan; forceps; hand lens or stereomicroscope; triple-beam balance; test tube; distilled water; test tube rack; sterile swab; petri dish of nutrient agar; tape
PRELAB PREPARATION: Review what you have learned about communities by answering the following questions:
• How does energy move through a community?
• What is an ecological pyramid?
• What role do decomposers play in a community?
PROCEDURE: Exploring a Soil Community
1. Form a cooperative group of four students. Work with one member of your group to complete steps 2-13. Make a table like the one shown on the opposite page. Steps 2-4 should be carried out in a nearby field or forest. The less disturbed your chosen area is, the better your results will be.
2. Collect the leaf litter from a 25 x 25cm (10 x 10 in.) area and place it in a plastic bag. Use a rubber band to seal the bag.
3. Observe the surface of the soil and record your observations in your table.
4. Use hand trowel to remove a cube-shaped sample of soil that measures about 15 cm (6 in.) on each side. Place the soil sample in a second plastic bag and seal the bag with a rubber band.
5. After returning to the lab, place both bags in the freezer for 5 hours or overnight. What is the purpose of freezing the bags?
6. Pour the contents of the bag of leaf litter into the pan and search for organisms. Using a hand lens or stereomicroscope, closely observe the organisms you find. Record your observations in your table.
|Sample |Types of |Observations |Mass |
| |Organisms | | |
|Soil |Animals | | |
|Surface | | | |
| |Plants | | |
|Leaf Litter |Animals | | |
| | | | |
| |Plants | | |
|Soil |Animals | | |
| | | | |
| |Plants | | |
| | | | |
| |Micro- | | |
| |Organisms | | |
7. Using forceps, separate the animal and plant material into two piles. Use the balance to find the mass of each pile. Return the leaf litter to the plastic bag.
8. Open the plastic bag containing your soil sample. Place a sample of soil about the size of a pea in a test tube. Add enough distilled water to the test tube so that the soil sample is covered in water.
9. Now perform steps 6 and 7 for the remainder of the soil sample.
10. Remove a sterile swab from its package. Dip the swab into the test tube containing the soil-water mixture. Remove the excess moisture by rotating the swab against the side of the tube. Open the cover of the petri dish and lightly rub the moistened swab over the surface of the agar in a zigzag pattern. Close the lid of the dish and seal it with tape, as your teacher directs.
11. Label the petri dish and incubate it at room temperature for one to two days. Then record your observations. Do not open the petri dish. After making your observations, dispose of the dish as directed by your teacher. What kinds of organisms are growing on the petri dish?
12. Share your observations with the other members of your group.
13. Clean up your materials and wash your hands before leaving the lab.
ANALYSIS:
1. Summarizing Observations:
Compare the leaf litter to the soil in terms of the mass and variety of animals.
2. Analyzing Observations:
What evidence suggests that an ecological pyramid exists in this community?
3. Analyzing Observations:
What evidence suggests that different trophic levels exist in this community?
4. Making References:
On what do the soil microorganisms feed in this community?
5. Comparing Observations:
How does the community you investigated compare to the community studied by the other team in your group?
THINKING CRITICALLY:
1. Is there evidence that predators occur in this community? Explain your answer.
2. Where does a soil ecosystem start and end? What are the boundaries of an ecosystem?
3. Suppose that a fire destroyed the leaf litter of this community. How would this disturbance affect the community?
35
ENVIRONMENTAL EFFECTS ON ORGANISMS: ACID RAID ON DAPHNIA
NAME: ______________________________________
TEACHER: ___________________________________
PERIOD: _____________________________________
DATE: ______________________________________
DUE DATE: __________________________________
NAME: ___________________________ DATE: ________________
HOW DOES ACID RAIN AFFECT DAPHNIA?
LAB # _34_
INTRODUCTION: In the pre-lab worksheet, you have read about some of the problems with acid rain. During this lab activity, you will be testing the effect of acid rain and another acid on a living organism—daphnia. Daphnia are small water insects that can be found in pond water. As a review, you will determine if a solution is an acid and it’s pH value.
STUDENT OBJECTIVES: You will be able to:
• determine if a solution is an acid using litmus and hydrion paper.
• record into a data table.
• make observations of animal behavior.
• predict the effects of acid rain on daphnia.
MATERIALS: Each group will get a test tube rack with four test tubes. T.T. #1-manufactured acid rain. T.T. #2-vinegar. T.T. #3-rain water. T.T. #4-tap water. Hydrion paper and color chart; hand lens or dissecting microscope; medicine dropper and glass rods; daphnia.
PROCEDURES:
TASK #1:
Test each solution in the test tube to determine if it is an acid. Use hydrion paper. To do this, take a clean glass rod or medicine dropper and place a drop of solution in the center of a piece of hydrion paper. Compare the color to the chart. Record results on Data Table 1.
DATA TABLE #1
|TT # |SOLUTION |HYDRION PAPER |ACID, NEUTRAL, OR BASIC |
| | |COLOR CHANGE |pH VALUE CHART | |
|1 | | | | |
|2 | | | | |
|3 | | | | |
|4 | | | | |
1. Does the rain water classify as “acid rain”? Explain.
______________________________________________________________-____________________________________________________________________________________________________________________________
2. What are the advantages for using hydrion paper?
__________________________________________________________________________________________________________________________________________________________________________________________
TASK #2:
Using the medicine dropper, transfer 6-10 daphnia from the sample jar to the 100 mL beaker. Be sure to add enough water so that the daphnia have enough room to swim freely. Two full droppers of water should be enough.
Observe their behavior using a hand lens or dissecting microscope. Write down your observations on the lab report page. Your observations should include their size, color, hours they swim, etc.
Number of daphnia observed ______________
Observations: ______________________________________________________________
2. What is the pulsating structure inside the daphnia’s body?
__________________________________________________________________________________________________________________________________________________________________________________________
3. Describe how the daphnia swim.
________________________________________________________________________________________________________________________________________________________________________________________________
4. Predict what you think will occur if you add “acid rain” to the daphnia’s environment. Be specific, when at what pH will the daphnia be affected?
__________________________________________________________________________________________________________________________________________________________________________________________
TASK #3:
1. Determine the pH of the water in the beaker with the daphnia as you did in Task #2. Record results in Data Table #2, in the start/original column.
2. Using a medicine dropper, add 10 drops of “acid rain” to the beaker with the daphnia and stir gently with a glass rod. Measure the pH, using hydrion paper. Observe the daphnia and record any changes in behavior. Be sure to wait at least 2 minute before adding 10 more drops of “acid rain.”
3. Repeat step #2, until you have reached 60 drops.
DATA TABLE #2:
| |start/ original |after 10 drops |after 20 drops |
| | |COLOR CHANGE |pH VALUE CHART | |
|1 | | | | |
|2 | | | | |
|3 | | | | |
|4 | | | | |
1. Does the rainwater classify as “acid rain”? Explain.
____________________________________________________________________
____________________________________________________________________
2. What are the advantages in using hydrion paper?
____________________________________________________________________
____________________________________________________________________
TASK #2:
Number of daphnia observed ____________
Observations ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
1. What is the pulsating structure inside the daphnia’s body?
__________________________________________________________________________________________________________________________________________________________________________________________
2. Explain how the daphnia accomplish locomotion.
__________________________________________________________________________________________________________________________________________________________________________________________
3. Predict what you think will occur, if you add “acid rain” to the daphnia’s environment. Be specific, when and at what pH will the daphnia be affected?
__________________________________________________________________________________________________________________________________________________________________________________________
TASK #3:
DATA TABLE #2:
|start/ original |after 10 drops |after 20 drops |after 30 drops |after 40 drops |after 50 drops |after 60 drops | |# of daphnia alive | | | | | | | | |pH of water | | | | | | | | |Behavior | | | | | | | | |
1. At what pH did you begin to notice behavior changes?
__________________________________________________________________________________________________________________________________________________________________________________________
2. At what pH did you notice your first death?
______________________________________________________________
____________________________________________________________________________________________________________________________
3. How many daphnia were still alive after 60 drops? _________ What was the pH reading at that point?
__________________________________________________________________________________________________________________________________________________________________________________________
CONCLUSIONS:
1. Why does the acid have harmful effects on living organisms? (Hint—enzymes)
__________________________________________________________________________________________________________________________________________________________________________________________
2. Hypothesize why some daphnia died off quickly while others remained alive?
__________________________________________________________________________________________________________________________________________________________________________________________
Check off what you have learned or done:
_ determined if a solution is an acid using litmus and hydrion paper
_ recorded data into a data table
_ making observations of animal behavior
_ predicted the effects of acid rain on daphnia
What else would you like to learn about this topic?
EXTENDING THE CONCEPT:
1. Do a library research project to find out why the Hudson River is not affected by acid rain.
__________________________________________________________________________________________________________________________________________________________________________________________
2. If you were a conservationalist, what could you do to a lake that had been polluted by acid rain so that fish and other organisms could live in it?
__________________________________________________________________________________________________________________________________________________________________________________________
3. Since people will continue to drive cars and industry will continue to produce waste, discuss some possible ways to deal with the acid rain problem.
__________________________________________________________________________________________________________________________________________________________________________________________
-----------------------
[pic]
Development in a human takes about 38 weeks. Many changes take place with the fetus during that time. Two changes that do occur are increases in size and mass. How much of a change in mass and size takes place each week?
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