Author: Biology Junction Team

Unsegmented Worm

Unsegmented Worms

All Materials © Cmassengale

Phylum Platyhelminthes
Characteristics

  • Called flatworms because bodies are flattened dorso-ventrally

  • Acoelomate – solid bodies without a lined body cavity
  • Have 3 body layers — outer ectoderm, middle mesoderm, & inner endoderm
  • Bilaterally symmetrical
  • Show cephalization (concentration of sensory organs at anterior or head end)
  • Body cells exchange oxygen & carbon dioxide directly with environment by diffusion
  • Single opening into gastrovascular cavity; two-way digestive tract
  • Some are parasites & others are free-living
  • Parasitic worms have thick cell layer called tegument covered with a nonliving cuticle covering their bodies as protection inside hosts
  • Includes 3 classes — Turbellaria (planarians), Trematoda (parasitic flukes), & Cestoda (parasitic tapeworms

Class Turbellaria

  • Most are marine but includes freshwater planarian (Dugesia)

Planarians

  • Spade-shaped at the anterior end & have two, light-sensitive eyespots
  • Can sense light, touch, taste, & small
  • Have 2 clusters of nerve cells or ganglia to form a simple brain
  • Nervous system composed of a nerve net
  • Capable of simple learning
  • Move by tiny hairs or cilia over a mucus layer that they secrete
  • Feed by scavenging or protozoans
  • Have a single opening or mouth located at the end of a muscular tube called the pharynx which can be extended when feeding
  • Flame cells help remove wastes to excretory pores

  • Hermaphrodites that cross-fertilize eggs that are then deposited into a capsule until hatching in 2-3 weeks
  • Reproduce asexually by fragmentation

Class Trematoda

  • Includes parasitic flukes
  • About 1 cm long & oval shaped

  • Require a host to live
  • Have both oral & ventral suckers to cling to host & suck blood, cells, & body fluids
  • Oral sucker around mouth at anterior end sucks blood
  • May be endoparasites (live inside a host) or ectoparasites (live on the outside of host
  • Covered in tough, unciliated tegument
  • Nervous & excretory systems like turbellarians
  • Hermaphrodites
  • Have a long, coiled uterus that stores & releases 10,000+ eggs
  • Eggs released through genital pore & develop into larva
  • Show complex life cycles
  • Life cycle of sheep liver fluke:
    * Adult liver flukes live in sheep liver & gall bladder where they mate & form eggs
    * Eggs enter intestines, pass out with feces, & hatch in water
    * Larva enter snails, asexually multiply, then leave snail & form cysts
    * Cysts (dormant larva with hard, protective covering) clings to grass
    * Sheep ingest cysts when they eat grass
    * Cysts hatch in digestive tract & bore through intestines into bloodstream
    * Mature & reproduce in the liver

  • Schistosomiasis (disease caused by parasitic blood flukes) infects people in Asia, Africa, & South America causing intestinal bleeding & tissue decay that can result in death

Class Cestoda

  • Includes tapeworms
  • Adapted for parasitic life
  • Tough outer tegument prevents being digested by host
  • Anterior end called scolex contains hooks & suckers for attachment to intestine of host

  • Long, ribbon-like bodies up to 12 m in length
  • Nervous system extends length of body but lacks sense organs
  • Lacks mouth & digestive tract but absorbs digested nutrients from host
  • Grows by making body segments called proglottids
  • Each proglottid produces eggs & sperm that cross-fertilize with other segments & also self-fertilize (hermaphrodites)
  • Oldest, mature proglottids containing eggs at posterior end break off & pass out with feces
  • Life cycle of beef tapeworm:
    * Cattle eat grass with proglottids containing fertilized eggs
    * Eggs hatch into larva & bore through cow’s intestine into bloodstream
    * Larva burrow into cow’s muscle & form cysts
    * Humans eat beef (muscle) & cysts travels to intestines
    * Cyst breaks open & adult beef tapeworm forms


BEEF TAPEWORM LIFE CYCLE

Phylum Nematoda
Characteristics

  • Called roundworms
  • Includes Ascaris, hookworms, Trichinella, & pinworms
  • Pseudocoelomates have fluid-filled body cavity partially lined with mesoderm
  • Pseudocoelom contains the body organs & provides hydrostatic skeletal support for muscles
  • Have long slender bodies that taper at both ends

  • Covered with flexible cuticle
  • Digestive tract with anterior mouth & posterior anus; called one-way digestive tract
  • Separate sexes in most species
  • Most are free living
  • Some are parasites on plants & animals
  • Ascaris is a parasitic roundworm living in the intestines of pigs, horses, & humans
  • Ascaris life cycle:
    * Enter body in contaminated food or water & hatch in intestines
    * Larva bore into bloodstream & carried to lungs & throat
    * Larva coughed up, swallowed, & return to intestines to mature & mate
    * Block the intestine causing death

  • Hookworm eggs hatch in moist soil & larva bore through bare feet of new host 
  • Trichinella are human parasites caused by eating undercooked pork containing the cysts
    * Cause disease called trichinosis
    * Cysts cause muscle pain & stiffness


 CYSTS IN CONTAMINATED PORK

Phylum Rotifera
Characteristics

  • Known as rotifers or wheel animals
  • Transparent, free-swimming microscopic animal
  • Freshwater & marine
  • Have a ring of cilia around mouth that rotates like a wheel to bring in food
  • Feed on unicellular algae, bacteria, & protozoa
  • Have a muscular organ called the mastax behind the pharynx to chop food
  • Nervous system composed of anterior ganglia & 2 long nerve cords
  • Show cephalization (head end)
  • Have 2 anterior, light-sensitive eyespots

Back

 

Scientific Method & Hand Size Lab

 

 

Using the Scientific Method

 

Introduction:

Humans are classified as a separate species because of all the special characteristics that they possess. These characteristics are controlled by strands of DNA located deep inside their cells. This DNA contains the code for every protein that an organism has the ability to produce. These proteins combine with other chemicals, within the body, to produce the cells, tissues, organs, organ systems, and finally the organism itself. The appearance of these organs, such as the shape of ones nose, length of the fingers, or the color of the eyes is called the phenotype.

Even though humans contain hands with five fingers, two ears, or one nose, there are subtle differences that separate these organs from another. There are subtle differences in a person’s genes that allows for these different phenotypes. In this lab, we are going to observe some of these differences in phenotype. All human hands look pretty much alike, but there are genes on your chromosomes that code for the characteristics making up your hand. We are going to examine two of these characteristics (hand width and hand length) and try to determine why these phenotypic differences occurred.

Materials:

  • metric ruler (see end of lab)
  • pencil
  • calculator

Procedures:

Day 1

  1. Choose a partner and have them measure the length of your right hand in centimeters. (Measure from the tip of your middle finger to the beginning of your wrist as shown in figure 1.)  Record your measurements in Table 1.
  2. Now measure and record the length in centimeters of your partners hand.
  3. Have your partner measure the width of your right hand, straight across the palm, and record the data in Table 1. (see figure 1.)
  4. Now measure & record the width of your partner’s hand.

Figure 1.

 

Table 1

 

Group Data on Right Hand Width and Length
Student Name Length of Hand (cm) Width of Palm (cm)

 

  1. After the entire class has completed Table 1, record your group data on the Class Data Table at the front of the room
  2. Record the Class Data Table information on your lab sheet’s Table 2.

Table 2

Class Data on Right hand Width and Length (cm)

Class Period:
Student Gender
(M / F)		 Hand Length (cm) Hand Width (cm)
1. M / F
2. M / F
3. M / F
4. M / F
5. M / F
6. M / F
7. M / F
8. M / F
9. M / F
10. M / F
11. M / F
12. M / F
13. M / F
14. M / F
15. M / F
16. M / F
17. M / F
18. M / F
19. M / F
20. M / F
21. M / F
22. M / F
23. M / F
24. M / F

Click for Class Data Table

Day 2

  1. In order to form a more accurate conclusion, the collection of additional data is necessary. Using the Class

. The teacher has the option to include the data from all the classes running this experiment. Below find tables that will allow the tabulation of several classes of data.

 

Table 3: All Classes Hand Length

Measurement of Hand length in cm. # of Males # of Females Total # ( Male + Female )
1.—————— ——————– ——————- ——————
2.—————— ——————- ——————- ——————-
3.—————— ——————- ——————- ——————-
4.—————— ——————- ——————- ——————-
5.—————— ——————- ——————- ——————-
6.—————— ——————- ——————- ——————-
7.—————— ——————- ——————- ——————-
8.—————— ——————- ——————- ——————-
9.—————— ——————- ——————- ——————-

 

Table 4: All Classes Hand Width

Measurement of Hand width in cm. # of Males # of Females Total # ( Male + Female )
1.—————— ——————– ——————- ——————
2.—————— ——————- ——————- ——————-
3,—————- ——————- ——————- ——————-
4.—————— ——————- ——————- ——————-
5.—————— ——————- ——————- ——————-
6.—————— ——————- ——————- ——————-
7.—————— ——————- ——————- ——————-
8.—————— ——————- ——————- ——————-
9.—————— ——————- ——————- ——————-

 

Line Graph the data from Tables 3 and 4. and then answer the questions that follow. Use the measurements of the width and length as your independent variable and the number of times that measurement appeared as your dependent variable.

Graph Tile: ___________________________________________________________

 

 

 

Analysis:

1. Examine the above graph. What is the shape of the line for hand length? _____________

________________________________________________________________________

2. What is the most abundant measurement for hand length? __________________.

3. What is (are) the least abundant measurement(s)? _________________________.

4. If we are to assign letters to represent the various lengths, what value(s) would we assign to the dominant genotype (HH)? ________________; the recessive genotype (hh)? ___________, and he heterozygous genotype (Hh)? _________________.

5. What would be the phenotypic name for the ( HH ) genotype? ___________________.

6. What would be the phenotypic name for the ( Hh ) genotype? ___________________.

7. What would be the phenotypic name for the ( hh ) genotype? ____________________.

8. Examine the above graph. What is the shape of the line for hand width ? ____________

________________________________________________________________________

9. What is the most abundant measurement for hand width? __________________.

10. What is (are) the least abundant measurement(s)? _________________________.

11. If we are to assign letters to represent the various lengths, what value(s) would we assign to the dominant genotype (WW)? ________________; the recessive genotype (ww)? ___________, and he heterozygous genotype (Ww)? _________________.

12. What would be the phenotypic name for the ( WW ) genotype? __________________.

13. What would be the phenotypic name for the ( Ww ) genotype? ___________________.

14. What would be the phenotypic name for the ( ww ) genotype? ___________________.

15. Are there any similarities in the graph of the above two characteristics? ____________.

16. If so, what are they? ____________________________________________________

17. Are there any differences in the graph of the above two characteristics? ____________.

18. If so, what are they? ____________________________________________________

19. Is there a difference in the length and width of the male and female hand? ___________.

20. Does the gender of a person have an effect on the phenotype of a trait? _____________.

Explain _________________________________________________________________

_______________________________________________________________________

________________________________________________________________________

 

Cut and use:

________________________________________________________________________

 

Thumb Wrestling Lab Sample1 Preap

Scientific Method – “I’m All Thumbs”

 

Introduction:

 

What makes a “Class Champion” thumb wrestler? Does thumb diameter, length, or wrist diameter have an effect on the overall chances of winning a thumb wrestling match? If you want to find out the answers to these questions then you have to do some scientific study. Scientific study is not only about plants and animals; it is also about how we function. You will have to use the scientific method to answer thesis questions. Scientific method is the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to demonstrate the truth or falseness of the hypothesis, and a conclusion that validates or modifies the hypothesis.

 

Hypothesis:

 

The person with the longest thumb will win the thumb war.

 

Materials:

 

The materials that were used for this lab was a metric ruler, metric tape measure, scissors, string, and a calculator.

 

Methods:

 

First you should choose a partner. Then measure the circumference of your thumb in centimeters at its widest point. Next you measure the length of your thumb, from the tip to the end of its second joint. Then measure the circumference of the wrist over the ulnar knob. Then you copy all of your information on the board onto the table in the results section of the lab.

 

Results:

 

Thumb Circumference Thumb Circumference (cm) Thumb Length (cm) Wrist Circumference (cm) Number of Wins
Cason, Drew 8.4 9 21.5 4
Dittrich, Chad 9 10 24 19
Holt, Brad 8 9.5 21 2
Hooker, Chris 7.1 9.3 21 2
Jones, Jett 8.5 9.8 21 6
Lambert, Scott 9.5 8 23 0
Lewis, Cody 8 9.5 20.5 1
Lockwood, Blake 8.3 8.5 21 0
Lorince, Alan 9.4 9.5 24 1
Moore, Clark 8.5 10 20 1
Phillips, Jaylon 9.3 10 24 1
Simpson, Jonathan 8 8.3 20 0
Smith, Zack 8.3 8.4 22.1 0
Williams, Paul 8.4 8 21 0
Yancey, Jey 9 10 22.5 0

 

Questions:

 

1. Restate your hypothesis: The person with the longest thumb will win the thumb war.

 

2. Which student won? Male: Chad Dittrich Female: Ashley Kersieck

 

3. What were their measurements: Male: thumb circumference-9cm, thumb length -10cm, and wrist circumference-24 cm.

Female Thumb circumference 7.0, thumb length 8.5, and wrist circumference 20.5

 

4. What was the mean thumb circumference of the class? 21.0

 

5. What was the mean wrist circumference of the class? 8.1

 

6. Did all those with larger measurements win their matches? No

 

7. Was your hypothesis correct? Yes

 

8. If not, explain what was different. It was right

 

9. What is the independent variable? Total of each contestant’s wrist and thumb measurements

 

10. What is the dependent variable? The number of

 

11. List the controlled variables in this experiment. Compete only in same sex, and follow all rules.

 

12. Would this be considered a controlled experiment? No

 

13. Explain your answer. Their were too many variables

 

 

Error Analysis:

 

The people wrestling might not have followed the rules by picking their arm up when they were wrestling or people just not trying would affect the outcome. Also people might have written their measurements in someone else’s place, which would affect the outcome as well.

 

Discussion and Conclusion:

 

The male who won the most thumb wrestling matches, nineteen wins, also had one of the longest thumb lengths, 9.0 centimeters. However, three other males with longer thumb lengths, 10.0 centimeters had fewer wins. Therefore the original hypothesis that the person(s) with the longest thumb length would also have the most wins was incorrect. If the measurements for each person were totaled or averaged together, then the persons with the greatest total measurement or highest average would have had the most wins. The current data would support this hypothesis.

BACK