Biology Assignment | Online Assignment

Homework
Here are three laboratory topics for your assignments, biology 100
1- Answer all questions on the topic with examples and pictures to support your answer.
2- Do not cut any part of the topics to make your answer clear, and do not leave any question without an answer.
3- Think and read carefully before answering and answer the data.

Homework

Here are three laboratory topics for your assignments, biology 100

1- Answer all questions on the topic with examples and pictures to support your answer.

2- Do not cut any part of the topics to make your answer clear, and do not leave any question without an answer.

3- Think and read carefully before answering and answer the data.

• Blood Typing & DNA Extraction Lab

 

Pre-Lab Questions: DNA.

1. In which organelle is DNA found?

 

 

2. What is chromatin?

 

 

3. What is the role of mRNA in the making of a protein?

 

 

4. What organelle does RNA work with to build proteins?

 

 

5. Define the following terms: surfactant, nucleotide, lyse, precipitate.

 

 

 

Pre-Lab Questions: Blood Typing

6. What is co-dominance? Which blood type is co-dominant?

 

 

7. What are the four human blood types? Are these phenotypes or genotypes?

 

 

8. What are the six possible genotypes that give rise to the four human blood types?

 

 

9. What is the Rh factor?

 

 

10. What are the A and B antigens and where can they be found?

 

 

11. What are the A and B antibodies and where are they found in the blood?

 

 

12. What is agglutination? (see picture on next page)

 

 

13. What blood type is the universal donor?

 

 

14. What blood type is the universal recipient?

 

 

Lab Activity A: Blood Typing

Objective:

To learn about patterns of inheritance and the ABO human blood groups

 

Materials

Gloves

white plastic blood typing trays

Synthetic blood samples –

Anti- B, Anti-A and Anti-D serums

Mixing toothpicks

Data table

 

The situation:

The nursery at City General Hospital is in turmoil. An hour ago, a violent storm damaged the hospital power plant, cutting off main power and almost all generator backups.

 

During the storm, Kim gave birth to fraternal twins and Andrea gave birth to one baby. The healthy babies were whisked to the nursery where a portable generator was available. The babies were measured, tested, cleaned, and swaddled. Just as Nurse Getwell was about to return the babies to their mothers for their feeding, she discovered that the identification protocol was forgotten in the confusion of the storm and power outage. She has no idea which of the three babies are fraternal twins, and she doesn’t know which babies belong to which mother!

 

Your job as a blood typing expert is to determine which of the two babies are fraternal twins belonging to Kim and which baby belongs to Andrea.

 

Procedure:

1. Glove up. Although this is synthetic blood and would not hurt you, we will practice proper blood handling protocol and wear gloves.

 

2. Label the white plastic blood typing trays: Andrea, Kim, baby 1, baby 2, baby 3.

 

Notice that the plastic trays have three wells and they are labeled A, B and Rh. 

 

3. Start with Andrea’s blood sample. Place one drop of blood in each of the three wells.

 

4. Place one drop of anti-serum A in the well labeled A and stir it gently into the blood sample with a toothpick. Next, place one drop of anti-serum B in the well labeled B and use a clean toothpick to stir gently.  Lastly, place one drop of anti-serum D in the well labeled Rh and stir gently with a clean toothpick.  Read and record the results in the data table below.

 

5. Repeat steps 4 and 5 for each remaining blood sample.

 

Agglutination = a positive result for that blood type

 

 

 

 

THE DATA TABLE:             Agglutination = Yes for that type

	Andrea	Kim	Baby 1	Baby 2	Baby 3
Anti-A serum
Anti-B serum
Anti-D (Rh) serum
Blood type

 

 

In this sample, the top right (well A) blood sample has been treated with anti- A serum and it has agglutinated which is a positive result for type A.  The top left (well B) blood sample has been treated with anti- B serum and it has also agglutinated which is a positive result for type B.  The bottom (well Rh) blood sample has been treated with anti-D serum which tests for the Rh factor and has not agglutinated which is a negative result for the Rh factor.  This person’s blood type is AB-negative

The solution: 

1. Which two alleles could Kim give her children for the ABO part of blood type?

 

 

1. Which two alleles could Andrea give her children for the ABO part of blood type?

 

 

 

1. Which baby could not be Kim’s? How do you know?

 

 

 

1. Which babies are fraternal twins? How do you know?

 

 

 

1. What ABO blood type must the twins’ father be? Use Punnett squares to support your explanation.

 

 

 

1. Who is positive for the Rh factor? What are the two possible genotypes that lead to being positive for the Rh factor?

 

 

1. Could two Rh-positive parents make a Rh-negative baby? Show Punnett square to demonstrate your answer.

 

 

1. Could a Rh-negative mother and a Rh-positive father make a Rh-negative baby? Show Punnett square to demonstrate your answer.

 

 

 

 

 

1. Could two Rh-negative parents make a Rh-positive baby? Show Punnett square to demonstrate your answer.

 

 

 

Lab Activity B: DNA isolation from banana fruit

Introduction

Deoxyribonucleic acid (DNA) is a molecule present in all living things, including bacteria, plants, and animals, and in almost all cell types. DNA is the carrier of genetic information.

A schematic representation of DNA (deoxyribonucleic acid). DNA is a long chainlike molecule that stores genetic information.

 

At the molecular level, DNA looks like a twisted ladder or a spiral staircase. A strand of DNA is made up of building blocks called nucleotides. Each nucleotide contains a five-carbon sugar, a phosphate group, and one of four possible nitrogen-rich bases: adenine, guanine, cytosine and thymine. The bases function like letters in a code, so they are abbreviated as A, G, C, and T.  Each base is connected to a sugar-phosphate “backbone”. Two strands of DNA wind around each other like a twisted ladder to form a double helix. Scientists have found that A always pairs with T, and G always pairs with C in double-stranded DNA.

 

DNA à mRNA à protein.

A DNA sequence is the particular arrangement or order of the bases in the DNA molecule. The sequences make messages that can be understood by cells, called genes. These genes contain the information to make proteins, which are the basis for most of an organism’s structure and nearly all its functions.

 

Why do scientist isolate (purify) DNA?

Since the structure of DNA was described in 1953, our knowledge of genetics has dramatically increased. Many thousands of investigations are being done all over the world using DNA sequence information and portions of DNA. For example, DNA is easier to isolate and study than proteins. The sequences of genes are used to form hypotheses on what the functions of encoded proteins might be based on evolutionary relationships between organisms. DNA is also used to determine evolutionary relationships, create screens for diseases, and even to find out if people are present at crime scenes. Given the rate we continue to acquire information, and how fast DNA technology is evolving, it is likely that technology and knowledge of genetics of all organisms, including humans, will be increasingly important in your lifetimes.

 

Isolating DNA

DNA is exceptionally easy to isolate from nearly any cell and requires very few chemicals and almost no equipment.  You will use a quick and easy procedure that scientists routinely use to extract DNA from different organisms.

The first step requires breaking open cells. For any examination of DNA, a sample must first be obtained.  We will isolate DNA from banana fruit. This can be done by adding cells (of any kind) to water and putting in a blender or by simply mashing them to lyse the plasma membrane.

The second step requires the addition of a detergent.  Detergents have surfactants that break surface tension and disrupt hydrophobic molecules like grease or membranes like those of a cell.  Therefore, the detergent breaks apart all the cellular membranes and liberates DNA from the nuclear membrane.

Lastly, alcohol is added to the solution.    Alcohol is lighter than the water and DNA will float in the alcohol layer, separating it from the heavier debris that settles in the water layer.

 

 

Materials:

10% SDS Detergent Solution, ~5 ml

95% ethanol, ice cold, ~10 ml

• 50 ml tubes with caps
• banana slice
• wooden tongue depressor

1    piece of gauze

1    thin wooden stick

5 ml tap water

 

Procedure:

1. Put a banana slice into a 50ml tube and mash it up very well with a tongue depressor.

 

2. Add ~5 ml of tap water to the tube.

 

3. Add ~5 ml of 10% SDS Detergent Solution to the tube.

 

4. Put the cap on the tube and close it tightly. Mix the solution by gently for several minutes by tipping the tube up and down. Gentle mixing is important because you want to keep detergent foaming to a minimum.

 

5. Place a piece of gauze over the tube with the mashed banana solution. Hold the gauze tightly over the top of the tube and pour the liquid into a second 50ml tube. To collect enough of the liquid, use your fingers to manually squish the liquid out of the gauze and into the new tube.  Set the banana mush and gauze aside for disposal.

 

6. Tilt the tube with the liquid slightly and add all 10 ml ice-cold ethanol to the second tube of filtered liquid by pouring it very slowly down the side of the tube. The DNA should form a stringy white precipitate at the top of the tube.

 

7. Spool the DNA onto the wooden stick by dipping it into the ethanol mixture and turning it. Do not mix the two layers of liquid.

 

8. Lab Cleanup: Put all items and tubes with caps back where you found them.  Do not pour any solutions down the drain! Place all solutions in the waste container provided on the cart.

 

Post Lab Blood Typing Practice – see Canvas for answer key

 

1. Justin has type A blood and his wife Brittany has type B blood. Justin’s parents both have type AB blood, and Brittany’s parents also both have type AB blood. What are the chances that Justin and Brittany’s son Theodore has type A blood? Use Punnett squares to demonstrate your answer.

 

 

 

 

 

 

2. A car accident occurred and Mary, a young pregnant student, was rushed to the emergency room after being hit by a turning car while legally crossing an intersection. She would require several units of transfused blood.

While in the emergency room, Mary’s blood was typed as AB negative, a very rare type. The hospital had no AB negative in the blood bank. Calls were made to other blood banks and no AB negative blood was immediately available. Several B positive, O positive and O negative units of blood were located at the Red Cross.

 

While in the emergency room Mary had an emergency C-section and safely delivered her baby, Brandon. But alas, soon after delivery Baby Brandon was in great distress with some type of autoimmune reaction and required a total blood transfusion. His blood was typed as A positive by the lab technician.

 

1. What is Mary’s genotype for her blood type?

 

1. What are the two possible genotypes for the baby’s blood type?

 

1. Can Mary donate to her baby? Explain why or why not.

 

1. Which of the available blood phenotypes can Mary be given? Explain why?

 

1. Which of the available blood phenotypes can be given to the baby? Explain why?

 

1. What are the all possible blood phenotypes and genotypes of the father? Use Punnett squares to demonstrate your answer.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2- Exploring Animal Diversity Part 1 – Invertebrate Dissections Lab

 

Objectives

• Identify invertebrate animals at the phylum and class level
• Participate in your groups’ dissection of a Mollusk and an Arthropod
• Identify major anatomical structures and their function on the laboratory specimens
• Learn about Echinoderm, Nematode anatomy by observing pre-dissected animals.

 

Pre-Lab Questions and Activities

1. Are there any single-celled animals?

 

 

2. Fossil and molecular evidence suggest that the common ancestor to all animals was likely what type of organism?

 

 

3. Which are more numerous, animals without a backbone (invertebrates) or animals with a backbone (vertebrates)?

 

 

4. In preparation for the crayfish dissection please watch this video: Crayfish Dissection
5. In preparation for the squid dissection please watch this video: Squid Dissection

 

Introduction

Biologists have found several characteristics that ALL animals have in common and have generally settled on these descriptive characteristics to define what it is to be an animal.

1. Eukaryotic: All animals belong to Domain Eukarya and possess eukaryotic cells.
2. Multicellularity: There are no single celled animals. However, multicellularity in animals ranges from the tiniest invertebrate Cnidarian the Myxozoa composed of just a few cells to vertebrate organisms such as us with trillions of cells.
3. Heterotrophic: Animals cannot photosynthesize. All animals must obtain energy by ingesting essential organic molecules such as carbohydrates, lipids and proteins.
4. No cell walls: All animals lack cell walls which are found in other eukaryotic organisms such as plants and fungi.
5. Active movement in at least one stage of life: Whether its waddling, swimming, flying, burrowing, undulating, running or walking – all animals locomote.    Although many animals are sessile as adults their larval stage is motile, allowing them to disperse away from their parents before settling down.
6. This last one is a ‘MOST animals’ statement: Presence of special proteins like collagen: Most animals (except sponges) have collagen and other extracellular proteins which are unique to animals. These proteins provide structural support and connection to other cells.

 

Over the next two labs meetings we will be learning about the animal diversity found in nine different phyla.  You will have the opportunity to observe both live and preserved specimens of several members found in these nine animal phyla.  In part one we will focus on five of the phyla: Nematoda, Echinodermata, Platyhelminthes, Mollusca and Arthropoda.  Let’s get started!

Phylum Nematoda

The first of three ‘worm’ phyla we will study, nematodes are the roundworms. There are ~25,000 identified species but likely ten times that number have not been identified yet.  Nematodes owe their round shape to the presence of a pseudocoelom and can range in length from less than 1mm to more than a meter.  They are some of the most abundant animals on the planet and are found in every conceivable ecological niche.  Free-living and parasitic roundworms can be found in every environment; fresh and sea water, hot springs, mountain tops and deep oceans.  They can be found on land, in deserts and polar regions and some species can be found in the moist tissues of plants and body fluids/tissues of many different invertebrate and vertebrate animals.  An acre of fertile soil can contain as many as 5 billion nematodes.  Free-living nematodes play a major role in decomposition of organic matter and nutrient recycling, but little is known about most species; because of their importance to agriculture, research has focused primarily on plant-parasitic nematodes.  One of the most common nematode parasites in humans is Ascaris lumbricoides. This is an intestinal roundworm that infects approximately 20% of the world population. A single female nematode can produce 200,000 eggs/day. The eggs can survive for years in the soil. Interestingly, there is no evidence of asexual reproduction in roundworms and the sexes are separate with the male considerably smaller than the female.

After eggs are swallowed , the larvae hatch , invade the intestinal mucosa, and are carried via circulation to the lungs . The larvae mature further in the lungs (10 to 14 days), penetrate the lung walls, ascend the to the throat, and are swallowed . Upon reaching the small intestine, they develop into adult worms. Adult worms can live 1 to 2 years.  Highest prevalence in tropical and subtropical regions, and areas with inadequate sanitation. Occurs in rural areas of the southeastern United States.

 

 

 

 

 

 

 

Examine the pre-dissected male and female Ascaris roundworm.

1. Glove up – be sure to wear protective gloves when examining roundworms!
2. Examine the dissected nematodes and on a separate sheet of paper make a simple drawing of each worm.
3. Label the following things on your drawings: male or female, intestines, ovary or testes and the anterior (head) and posterior (rectum).

 

 

 

Phylum Echinodermata

Members of Echinodermata are found only in the marine habitat. They include sea stars, brittle stars, sea urchins, sand dollars and sea cucumbers and can be found from the shallow intertidal zone to the deep oceans.  There are ~6500 living species of echinoderms in the world.  Echinoderms often have spiny skin due to their endoskeleton which is made of calcium rich plates beneath their epidermis.  They do not have a true heart, head or centralized brain but they do have a nerve net type nervous system that is highly developed in some members of the phylum.  One of the coolest features of these animals is their mutable connective tissue.  When threatened, nerve impulses rapidly and dramatically alter the degree of stiffness and fluidity of their connective tissue – in some species rock hard tissue can practically liquify in a fraction of a second and revert back to extreme stiffness equally quick! This defense mechanism allows the animals to easily shed an arm and live to regrow it later.  Although they may not look like it at first glance, echinoderms are considered bilateral animals. However, it is usually only the larval stage which displays obvious bilateral symmetry (see photo). Echinoderms have a unique water vascular system. They essentially use hydraulic mechanisms for locomotion, feeding, excretion and respiration. It works by water entering the system through a hole on the dorsal surface called the madreporite. From the madreporite water travels through a small tube to a ring canal (a circular tube in the center of the animal). From the ring canal, water then extends into the radial canals in each arm. From the radial canals, water enters the tube feet on the ventral side of a sea star. Attached to each tube foot is an ampulla which acts as a water bulb – controlling the amount of water in each foot. When the ampullae contract, water is forced into the tube feet and is prevented from going back into the radial canals, thus the tube foot is extended. Once extended the tube feet can attach to a surface as some tube feet have suckers. Then muscles in the tube feet contract and force water back into the ampulla that retracts the tube foot and drags the body along or aids in feeding.  Check out this excellent video of a sand dollar doing using its tube feet: Sand dollar in action

 

 

Examine the pre-dissected Sea Star

1. Sea stars are not parasitic and fresh ones can be touched without gloves (you can touch some live ones at the marine lab). Our sample is preserved so it is best to use gloves as the preservative is nasty stuff.
2. Examine the dissected sea star and on a separate piece of paper make a simple drawing.
3. Labe the following things on your drawing: madreporite, ring canal, arms, radial canal, ampullae, tube feet.

 

Phylum Platyhelminthes

The second worm phylum we will study are known as the flatworms.  There are ~20,000 species of flatworms.  They can be found in both marine and fresh water and in moist terrestrial habitats.  Animals in this group are acoelomates which is why they are flat.  Free living flatworms such as planarians, parasitic flukes and parasitic tapeworms are all members of Platyhelminthes. They have bilateral symmetry with a right side and a left side. Flatworms have heads and some have primitive brains, but overall their nervous systems are quite simple.  They do not have a circulatory system or blood which carries gases instead gases are easily exchanged across their thin body walls.  Free-living flatworm digestive systems have a single opening called a pharynx which used for ingesting food.  Parasitic flatworms lack a digestive system as their food is already digested by the host organism.  Planarians are fresh water flatworms that play an important role in aquatic food webs and are often used as bioindicators to determine the health of an ecosystem.  Marine flatworms are some of the most beautiful and bizarre ocean creatures; they are usually brightly colored and commonly found in coral reefs around the world.  Be sure to check out this fascinating mating ritual carried out by marine flatworms: Marine Flatworm Penis Fencing

 

Examine the live planarian flatworms that are set up on the stereomicroscope.

1. Draw a simple picture of the flatworm.
2. Label the following structures: anterior (head), posterior, ocelli and auricles.

 

 

Handling and Cleanup Procedures for Dissections

• When you are done, discard materials as instructed.
• Use soap to clean tools and tray.  Set them out on paper towels or matting, as instructed, so they can dry properly.  Use paper towels to dry the inner edges of scissors; then, set them on the drying material with blades open.  Place like instruments together and so they are facing the same direction.  Please be very careful when handling scalpels!
• Return reusable supplies to the cart if they were not set out to dry.
• Use disinfectant to clean your bench area.
• Wash your hands!

 

Crayfish Dissection – Phylum Arthropoda

Members of the Phylum Arthropoda predate dinosaurs by 50 million years and include insects, spiders, ticks, mites, scorpions, centipedes, millipedes, horseshoe crabs, and crustaceans. Arthropoda has more species than any other phylum because of its insect members. There are more species of insects than the number of all other species of animals combined. Arthropods can be found in every ecological niche imaginable and were the first animals to inhabit land ~460 million years ago. They were also the first to evolve the ability to fly. In addition to having a segmented body, they also have paired jointed appendages, a complex muscular system and an exoskeleton that is hard but flexible.

 

Today your group will be dissecting an aquatic crustacean known as a crayfish (its not really a fish!) although many people refer to crabs and the like as ‘shell fish’. I recommend watching this helpful dissection video before or during your dissection: Crayfish Dissection

 

Materials

Crayfish                                                Probe

Dissection pan                   Gloves

Scissors                                Camera*

*Elect one member of your group to stay clean and operate the camera and take notes as needed.

 

External Crayfish Anatomy

1. Glove up. Obtain a crayfish and rinse it with water then place it in the dissection pan.

 

2. Is this crayfish a male or a female? Larger crayfish are the males, smaller ones the females.
3. Identify the three regions of the body: the head, the cephalothorax and the
4. Identify the compound eyes on the rostrum portion of the head.
5. Note the larger antennae and smaller antennules protruding from the
6. On the ventral side of the head, locate the mouth with the mandibles, or true jaws. The mandibles tear the food, and the other appendages detect and hold food during feeding.
7. Identify the carapace covering the cephalothorax.
8. There are five pairs of walking legs connected ventrally to the carapace region. The first walking leg has enlarged pincers called chelipeds. They are used to manipulate objects and capture and crush food.
9. On the ventral side of the abdomen, there are numerous swimmerets. The first pair is modified for the transfer of sperm in those that are ready to mate.
10. Identify the uropod and the telson at the posterior end of the abdomen.
11. Take two photos highlighting the external anatomy – note: photos will be inserted into the post-lab portion of this document.

 

 

 

 

 

 

 

 

 

 

Internal Crayfish Anatomy

1. Examine the gills: to expose the feathery gills underlying the carapace, use scissors to cut away a portion of the plate on the left side of the animal. Remove one of the walking legs and note that the gills are attached.  The legs are attached to the gills so that each time the animal moves its legs the gills are bathed in oxygen rich water.

 

2. Take a photo of the gills.

 

3. Using the scissors, carefully remove the remaining part of the dorsal carapace. Start at the posterior part of the cephalothorax and cut up the middle of the exoskeleton until you reach the head.  Gently peel back the exoskeleton using your probe to tease away the muscles which are attached to the exoskeleton.

 

4. Observe the diamond-shaped heart, a small, angular structure located just under the carapace near the posterior portion of the thorax. If you cannot locate the structure, check the carapace – it may have been removed with your flap.  Thin threads leading away from the heart are the arteries.

 

5. Locate the stomach in the head region. It will be a large, sac-like structure.  It may be obscured by the large, white digestive glands that fill the body cavity inside the body wall.  Remove the stomach and open it up – you should be able to see the brown teeth that line both sides of the stomach.

 

6. Take a photo of the stomach.

 

 

7. Leading posterior from the stomach is the intestine. Make a cut through the exoskeleton on the dorsal side of the abdomen.  Lift the exoskeleton and trace the intestines to the anus.

 

8. Take one more photo of your fully dissected crayfish.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Squid Dissection – Phylum Mollusca

This highly diverse phylum has ~110,000 species described and includes animals such as chitons, snails, slugs, octopus, squid, mussels and clams.  Thanks to the gastropods, mollusks range from the deep seas to mountain tops and from lakes to deserts.  All mollusks have a generalized body plan consisting of three main body regions: muscular foot, visceral mass, and mantle. The muscular foot region is the locomotory and sensory portion of the body, upon which rides the visceral mass containing the excretory, digestive, and circulatory organs. The third component of the body, the mantle, forms a fleshy cover over the visceral mass and a skirt around the foot. It secretes the shell (when present), contains the gills and functions in respiration. The mantle displays a great deal of variety in form and function within the phylum.  Each of the mollusk classes reflects the elaboration or suppression of one or more of the three body regions. Although primarily marine, representatives are found in fresh water and on land.

Today your group will dissect a fresh squid.  Squid are members of the class Cephalopoda (cephalo = head, poda = foot) that includes squid, octopus, cuttlefish, and nautilus.  The prominent head with its’ tentacles and arms is a modification of the muscular foot that is responsible for holding closed the shells of many other members of this phylum.  The coelom is reduced in most mollusks and is usually restricted to the area surrounding the heart and to spaces within the gonads and kidneys. Most mollusks are slow-moving, creeping animals, but in cephalopods the organization of the body regions has been modified so that swift movements are possible via jet propulsion.  I recommend watching this dissection video before and/or during your dissection: Squid Dissection

 

 

 

Materials

Squid                                     Forceps

Dissection tray                  Probes

Scissors                                Gloves

Pins                                        Camera*

*elect a member of the group to stay clean and take photos and notes.

 

External Squid Anatomy

1. Glove up. Obtain a squid and rinse it in water then place it in the dissection tray.

 

2. Identify the soft mantle that contains all the internal organs – it is sharply demarcated from the rest of the squid body by the collar. Identify the fins which protrude from the mantle.

 

3. Opposite the pointed end of the animal (the apex), is the foot

 

4. Notice the colored spots on the outside of the squid, these are Muscles attached to these cells expand and contract to allow the squid to change color. The squid camouflages to protect itself and communicate.

 

5. Identify the eight arms and two longer tentacles that are derivatives of the muscular foot and surround the mouth. Arms have two rows of suckers and are not retractable. Tentacles have four rows of suckers on an enlarged tip of the tentacle referred to as a  Unlike arms, tentacles are retractable being shot out to capture prey and shortened to bring it into the mouth.  Check it out this video of a cephalopod tentacle in action: Cephalopods are clever hunters

 

6. Take a photo of the tentacles.

 

7. Feel the horny beak protruding from the mouth. This beak is used to tear apart captured prey. We will take a closer look at it when dissecting the head later.

 

8. Locate the large, well-developed eyes and the fold of tissue behind the eye, called the olfactory crest. This organ is for sensing chemicals in the water (chemoreception) and is positioned in the incurrent flow of the mantle cavity.

 

 

 

 

9. Place the animal so the apex is furthest from you and the arms are closest to you. Turn the animal so that the siphon (the tubular projections between the collar and the foot) is facing you. It too is a derivative of the foot. In life, the mantle cavity expands by muscular action, water enters, and the collar locks tightly against the head, leaving the siphon as the only exit pathway from the mantle cavity. The muscular siphon can be pointed for making directed jet-propulsive movements.

 

10. The mantle surrounds most of the organs of the body and within the mantle is the mantle cavity, housing the digestive, excretory, and reproductive systems.

 

 

Internal Squid Anatomy

1. With the siphon facing up, have one partner pinch the mantle. With the scissors make a shallow cut to avoid damaging internal organs that runs the entire posterior surface from siphon to apex.

 

 

 

 

 

 

 

 

 

2. Pin the cut mantle edges on the sides to expose the internal organs clearly. See photo below.

 

3. Take a photo of your pinned squid.

 

4. Locate the siphon (also called the funnel). Note that the tip of the siphon has a valve that regulates the outflow of water from the mantle cavity.

 

5. Feel the for the ridges inner side of the mantle. These cartilaginous ridges are part of the animals’ skeleton.

 

6. Locate the delicate paired gills referred to as ctenidia. These gills have ciliary filaments to move water and are oriented so that the inhalant streams pass over each, then converge and exit as a single exhalent stream.

 

7. Locate the rectum ending in the anus at the base of the siphon. The location of the anus may seem peculiar at first however it is quite brilliant as the siphon ensures that feces are easily flushed away from the animal!

 

8. Cephalopods have three hearts; one for each gill (brachial) and one for the rest of the body (systemic). Locate the brachial hearts by gently pulling the gills straight up and trace them to where they meet.  In between the gills, is a yellow, soft ball that is the systemic heart.  Cephalopod blood contains a copper oxygen-binding pigment (unlike human blood that contains an iron oxygen-binding pigment), making it blue.

 

9. In the apex portion of the animal, pull back the thin peritoneum (saranwrap-like material) to expose the sex organs. Determine the sex of your squid.

• A female will have two white glands called nidamental glands along the midline. There may also be Vaseline colored organ at the tip full of eggs.  This is the gonad.
• A male will have lots of white tissue near the apex. This is a single large testis (sometimes easier to see after removing the left gill and branchial heart).  Just above the testis is the vas deferens, an opaque white tube.  Sperm packets (spermatophores) are stored in the vas deferens.  During copulation, the male uses a modified arm to pick packets of spermatophores from the vas deferens and transfer them to the female.  The female holds the gelatinous egg mass in her arms and attaches it to a suitable spot, usually rocks below the low tide mark. Young squid hatch within 2-3 weeks.

 

10. Take a photo of your squids’ gonads once you have determined the sex.

 

11. Identify the ink sac but be careful not to puncture it now, do that last. The ink is messy and permanent.

 

12. Locate the siphon retractor muscles which are attached to the siphon. Next, remove the siphon by placing your probe into the siphon on and cutting the siphon on each side.  Then retract the siphon completely back so that the head region is completely exposed.

 

13. The mouth is surrounded by eight pointed arms and two longer tentacles. Observe the structure of these arms and tentacles and the arrangement of the suckers. In life, the prey is grabbed by a rapid extension of the two tentacles and brought toward the mouth, where it is held firmly in place by the eight arms and killed by an injection of poison.

 

14. Inside the head is the buccal mass. Using the scissors, cut into the head and expose the buccal mass which is essentially the oral cavity of the squid. This is a muscular organ that bears two horny beaks which are used for ripping prey.

 

15. Expose the horny beaks by making a small cut with the scissors in the buccal mass and remove the beak. Check out how similar the beak is to a birds’ beak!

 

16. Take a photo of the horny beaks.

 

17. Use the scissors to open the head up to below the buccal mass and you should see the brain which looks like white cheesy material.

 

18. Identify the Peel the entire visceral mass away from the mantle to expose the pen which runs the length of the animal.  This is the internalized shell which lends support to the animal.

 

19. Lastly, check out the ink in the ink sac. Carefully puncture the ink sac and examine the ink.  The squid uses this ink for defense.  Be careful not to get the ink everywhere as it will stain clothing, but it is not toxic.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Post-lab Questions

1. What important role(s) do free-living nematodes play?

 

 

 

3. What would happen if we cut the planarian flatworm in half?

 

 

 

3. By what means does the sea star extend its tube feet?

 

 

 

2. What function do gills serve?

 

 

 

3. Why are the crayfish legs attached to the gills on the inside?

 

 

 

4. What type of skeleton does a crayfish have?

 

 

 

5. Which part of the squid is the muscular foot?

 

 

 

6. By what means do squid defend themselves?

 

 

 

7. How many hearts does a squid have?

 

 

 

8. Lastly, insert your pictures into this document and submit your completed lab via Canvas (see module for due date)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Food Web Lab

 

Objectives

Consider the concept of interconnectedness of species.

Become familiar with some of the food chains in the ocean’s food web.

Understand the different roles played by the organisms in an ecosystem.

Construct an ocean food web.

 

Introduction

Organisms within a community interact with each other and with the abiotic (nonliving) environment. In all instances, these interactions have two consequences:

1) a one-way flow of energy through autotrophs to heterotrophs which eat either autotrophs or             other heterotrophs; and

2) a cycling of materials, which move from the abiotic environment through the bodies of living                 organisms and back to the abiotic environment.

 

The combination of biotic and abiotic components through which energy flows and materials cycle is known as an ecosystem. Taking a global view, the entire surface of the Earth can be seen as a single ecosystem. This view is useful when studying materials that circulate on a worldwide basis, such as carbon dioxide, oxygen, and water.

 

All ecosystems have at least three trophic levels: primary producers, which are usually plants or algae; primary consumers, which are usually animals; and detritivores, which are organisms that live on animal wastes and dead plant and animal tissues. The primary producers (the autotrophs) convert a small proportion of the sun’s energy into chemical energy. The primary consumers (herbivores) eat the primary producers. A carnivore that eats the herbivore is a secondary consumer, and so on. About 10 percent of the energy transferred at each trophic level is stored in body tissue; of the remaining 90 percent, part is used in the metabolism of the organism and part is unassimilated (feces). This unassimilated energy is ultimately utilized by detritivores.

 

The passage of energy from one organism to another takes place along a specific food chain -that is, a sequence of organisms related to one another as prey and predator. The first organism is eaten by the second, the second by the third, and soon, in a series of feeding levels, or trophic levels. In most ecosystems, food chains are linked together in complex food webs, with many branches and inter¬ connections. Webs may involve more than 100 different species, with predators characteristically taking more than one type of prey, and each type of prey being exploited by several different species of predator. The relation of one species to others in its food web is an important function to its ecosystem.

 

The following.is a simplified example of a marine food chain: shorebirds eat clams buried in the sand for food; clams eat phytoplankton and zooplankton, which are brought to the beach by waves and currents; zooplankton eat other zooplankton and phytoplankton; phytoplankton are dependent upon inorganic nutrients (for raw materials) brought to the ocean’s surface by upwelling and the sun for energy to make their own food through photosynthesis.

Many food webs are fragile, and the removal of even one link in the chain may ultimately result in the collapse of the entire food web. Such a case may occur for the above example if upwelling, the movement of deeper, nutrient-rich water to the surface, does not take place one year (e.g., during El Nino). Without upwelling, the phytoplankton at the base of the food web cannot “bloom,” zooplankton cannot flourish, clams then cannot find enough to eat, and ultimately the shorebirds will have to concentrate on some other food item, move to another beach, forego reproduction that year, or starve.

 

Human made hazards are also potentially disruptive to the food web. Pollution from oil spills may block out the sun and disrupt photosynthesis in primary producers. Oil may coat shorebirds feathers, making it more difficult for the birds to keep warm; and silt carried downstream from construction and agriculture can smother bottom dwelling animals. These hazards could possibly remove a link in the food web and disrupt the entire web.  Animals would have to search for other food sources, which would result in higher competition between species for food. Since less food is available, the animal populations affected would decrease in numbers.

 

What do you think would happen if there was an oil spill in endangered species’ habitat? It could possibly lead to the collapse of the endangered species’ population in that area. Why would the disruption and possible destruction of a marine food web matter to us? It matters because all of life on Earth is interconnected and to whatever extent we make it less possible for ocean life to flourish, we make it that much less possible for life on land — including ourselves — to flourish.

 

 

Pre-Lab Questions:

1. What is an ecosystem?

 

 

2. What are the three major types of ecosystems on our planet?

 

 

3. Which ecosystem covers most of the planet?

 

 

4. How is a food chain different than a food web?

 

 

5. Define trophic.

 

 

6. What is biological magnification?

 

 

 

 

Some participants in the ocean food web:

Use the information in the table to construct an ocean food web.  You are not limited to these animals, feel free to research and use marine animals which are not in the table.

Name	Size	It Eats	Eaten By
Anchovy	7 inches	Phytoplankton & Zooplankton	Almost all larger fish, porpoises, sea lions
Angler Fish	6 – 12 inches	Shrimp, squid	Sea lions, Orca
Blue Whale	100 feet	Krill [tiny shrimp]
Gull	Wingspan 3 – 4 feet	herring, anchovies, squid, and sardines	Orca
Halibut	3 – 6 feet	anchovies, octopuses, sardines	Sharks, sea lions
Harbor Seal	5 – 6 feet	squid, rockfish, small sharks, salmon, sardines	sharks and orcas
Orca	20-30 feet	seals, sea lions, most fish [especially salmon], squid and marine birds
Octopus	Up to 3 feet	anchovy, sardine, herring and shrimp	tuna, swordfish, halibut
Pacific Herring	12 inches	Phytoplankton & Zooplankton	most larger fish, birds and mammals
Pelican	Wingspan 7 feet	herring, anchovies, squid, and sardines	Orca
Phytoplankton	Microscopic	obtains food from the sun and nutrients in the water	Zooplankton, anchovies, herring, sardine, shrimp
Porpoise	7 feet	squid, herring, anchovy, rockfish, sardine, shrimp	sharks and Orca
Rockfish	2 feet	Smaller fish, especially sardines, anchovies	Seals, Porpoises, Sea Lions, Sharks
Salmon	3 feet	squid, anchovies, rockfish. herring	seals, sea lions, sharks, Orca
Sardine	12 inches	Phytoplankton & Zooplankton	most larger fish, birds and mammals
Sea Lions	6 – 8 feet	Anchovies, Halibut, Salmon	Orca
Shark	20-30 feet	halibut, rockfish, salmon, seals, anchovies and porpoise
Shrimp	1 – 2 inches	Phytoplankton & Zooplankton	angler fish, porpoises and squid
Squid	12 inches	small fish, shrimp	larger fish, mammals
Swordfish	12 feet	anchovies, squid, octopuses, mackerel, rockfish, deep sea fish	sharks and Orca
Yellowfin Tuna	5 feet	herring, anchovies, squid, sardines, shrimp	sharks and Orca
Zooplankton	Microscopic	Phytoplankton	anchovies, blue whale, herring, sardine, shrimp

 

1. Construct a series of eight food chains, using the table below. In the first column, put the producer at the base of each chain, followed by the first consumer that eats it directly, then the second consumer that eats the first consumer, and so on to the top of each chain. It’s expected that you will use organisms in more than one food chain. Color-code each chain so you can distinguish them from each other.

 

Color	Producer	1st consumer	2nd consumer	3rd consumer	4th consumer	5th consumer

 

2. On a large piece of paper, draw each of your food chains, starting with the producer in the middle of the paper, extending each food chain out to the edge. Indicate the connection between each life form and its prey with lines using the color(s) you assigned to that food chain.

 

3. When all eight food chains are depicted, analyze the connections among them by connecting life forms as they appear in more than one food chain. This will graphically demonstrate the “webbing” of the food chains into a food web.

 

4. Take a photo of your food web and insert it into this document, then submit your completed lab via Canvas.

 

Post-Lab Questions

1. How does the size of the organism generally relate to its position in the food web? Are there any exceptions to this generalization? Explain your answer.
2. How many trophic levels do you have on your marine food web? Diagram them with an energy pyramid.
3. Which trophic level do you think has the greatest number (or mass) of organisms? Why?
4. Which level seems to have the greatest diversity of species? Why is species diversity (or species richness) important to an ecosystem?
5. Some organisms are dependent on one food source while others rely on many different food sources. Which is more able to withstand changes in the ecosystem? Why?
6. What do you think would happen if an oil spill occurred that killed off most of the phytoplankton and zooplankton?
7. What might happen if a chemical such as DDT, which negatively affects organisms at higher trophic levels, were added to the ocean ecosystem? (Hint: think bioaccumulation)
8. How are detritivores or decomposers important to an ecosystem?
9. Upload your completed lab to Canvas no later than the final day of the quarter!