Introduction
The objective of this report is to summarize the key methods, procedures, goals and objectives, and takeaways from a series of individual laboratory experiments conducted throughout the course. Specifically, it is a summary of Exercises 1 on Phylum Porifera (Sponges), 2 on Phylum Cnidaria (Hydras), 3 on Phylum Platyhelminthes (Planarians), 4 on Phylum Annelida (Clamworms and Earthworms), 5 on Phylum Mollusca (Clams), and other exercises on Phylum Arthropoda (Crayfish), Deuterostome (Phylum Echinodermata, Sea Star), among others. Despite their number, the individual laboratory experiments, in fact, have one thing in common. That is their key objective is to be able to identify and describe the characteristics that make each of the animal groups being discussed unique.
Materials and Methods
For the virtue of comparison, the author of this paper listed down the materials that were used for each laboratory experiment. This is because the materials used can be very specific to the type of organism being reviewed. For the methods section though, it was written collectively, because after all, the objective of each of the laboratory experiment was similar. It is on the results and findings where they actually differed on a per experiment basis.
Materials
Exercise 1 Phylum Porifera – Sponges (Scypha)
Dissecting needle
Compound microscope
Stereoscopic microscope
Preserved and dry bath sponges
Longitudinally dissected slide of Scypha
Preserved Scypha in a watch glass
Exercise 2 Phylum Cnidaria – Hydras (Hydra)
Stereoscopic and compound microscope
Depression slides, wat glasses, bulbs and pipettes, dropper bottles, acetic acid, methylene blue
For the specimens, the following were prepared: living Hydra culture and water flea cultures; different Hydra specimen body segments were also prepared
Exercise 3 Deuterostome – Phylum Echinodermata – Sea Star
Sea Stars and several dissected parts of Sea Stars including the internal contents, and ones that show the oral and aboral parts or halves of its body
Exercise 3 Phylum Platyhelminthes – Planarians (Dugesia)
Stereoscopic and compound microscopes
A planarian specimen (i.e. free-living flatworm characterized by a dorsoventrally flattened body cavity, including cross sectioned body components for dissection.
Watch glasses
Exercise 4 Phylum Annelida – Clamworms (Neresis) and Earthworms (Lumbricus Terrestris)
Earthworm and Clamworm specimens, dissected and living
Glass slides for observation
Exercise 5 Phylum Mollusca – Clams
Dissecting pan and other dissecting instruments
Gloves
Preserved clams and or mussels
Exercise 2 Phylum Arthropoda
Dissecting pan and dissecting instruments
Crayfish
Disposable gloves
Methods
For the method component, excluding all the animal-specific components and objectives, it was rather universal across all experiments. Based on the materials that were listed for each laboratory experiment, it can be deducted that the method that was predominantly used throughout the lab report series was observation. The specimens reviewed throughout all laboratory experiments varied in sizes, shapes, and characteristics. This is why numerous tools for observation were devised and utilized. Some of the most common ones included the stereoscopic and compound microscope. These were used to observe the cell structures and arrangement of the animal specimens, depending on what experiment one is pertaining to. Watch glasses, glass slides, dissecting plans, and gloves were used to manipulate the specimens and observe them. Watch glasses were used specifically to observe the animal specimens that can actually fit inside them. The glass slides were used to display the dissected body structures of the animal specimens either for microscope or naked eye viewing. Either way, the fact that the predominant method of gathering information and confirming the hypotheses used in the laboratory experiment series was inspection and observation. This can so far be manifested by the fact that majority, if not all, of the artificial tools brought in for all laboratory experiments were typically used for observation.
One laboratory experiment that is worth noting here would be the Sea Star experiment. So far, it was the only experiment where the only type of observation used was gross—meaning, without the use of any observation device. This may be due to the fact that the size of the specimens (i.e. a star fish) used was large enough to rule out the use of any assistive observatory apparatuses such as the microscope. In the said experiment, the procedure involved the determination of the presence and the characteristics of the specimen’s aboral and oral surfaces, the central disks, the madreporite, endoskeletons, mouth, tube feet, the skin gills, and the true body cavity and the organs that are enclosed in it.
Then again, the fact that the laboratory students used the method described in this laboratory experiment narrative in gathering information and learning more about their specimens from different animal species (from the taxonomic rank of phylum) holds true. Much of the learning and discovery was obtained from the laboratory experiments that involved the use of dissected specimens because through this, the lab researchers were able to check the insides of their specimen, something which they typically would not be able to do just by simply observing them from the outside. Additionally, they would be able to palpate the different parts of their specimen and be able to check and verify the validity of their hypothesis along the process. An interesting discovery, for example, would be in Exercise 3 – Phylum Platyhelminthes Planarians (Dugesia). Using the compound and stereoscopic microscope, one would be able to determine that flatworms, just like earthworms, have a distinct digestive tract in that they also have their food enter their body through their mouth and exit it from their anus. This is a kind of an interesting discovery about flatworms because the common notion, especially among biology students, is that flatworms have a unique digestive system, not knowing that like most animals, they have a mouth and anus as the initial and end point, respectively, of their digestive tract. Additionally, this is a kind of observation that would not have been possible without the use of the microscopes, unlike in other animal specimens where gross observations of the specimen’s outer body and dissected body parts would have already been enough to gather the said information and verify their hypotheses.
Results
In the case of the laboratory exercise 2 about the phylum Cnidaria (Hydras) for example, the goal of the experiment was to check the similarities and differences that may have arisen secondarily or through secondary simplifications among the sample species included (e.g. corals, jellies, sea anemones, and Portuguese men of war). The hypothesis or what the researchers hoped to observe from this experiment suggests that hydras supposed to be described with the following characteristics: umbrella like, free-swimming, cylindrical in shape (or at least the largest parts of their body), and can either be in an attached or stationary form. The different specimens, at least for this experiment were also compared in terms of their body shape (e.g. symmetry), distinct physical features (e.g. appendages), segmentation, locomotion, and even internal organ systems (circulatory systems as an example), among others. This was just one of the laboratory experiments that were conducted in this series of laboratory experiment projects. Then again, the key objective was to be able to successfully describe the main characteristics that describe each subject organism. Derived from the laboratory manual, the criteria for comparison included the following:
Symmetry
Describes the animal’s total form by observing its medial and lateral body components, if it has mirror images, or even if its appendages are present bilaterally; in general, symmetry can be described using two simple terms: symmetrical or asymmetrical
Tissue Organization
The subject animals, at least in some experiments, were also described based on their tissue organization or how their cells are organized, based on structure and function.
Body Cavity
It is important to note that some animals have an existing body cavity (as in the case of animal guts) while some do not, or at least may not be obvious due to some unique bodily characteristics. Animals can be described as acoelomate, pseudo-coelomate, and coelomate, according to the absence, presence, and characteristic (if present) of their body cavity.
Digestive Tract Openings
The rationale behind describing the digestive tract openings of the subject animals is to describe how the food enters and leaves their body as waste materials. In some animals, for example, as in the case of grasshoppers and crayfishes, food, depending on what they eat, enters from their mouth, follows a unique digestive tract, until they excrete the digested food as wastes through their anus. It is important to note, however, that no matter how common, some animals may not exhibit the same characteristic.
Circulatory System
The goal in describing the subject animals’ circulatory system is to detect whether they have an open or a closed type of circulation.
Habitat
The subject animals can be divided into two groups based on their habitat: terrestrial (those who live on land) and aquatic (those who live in water, which can either be sea or fresh water).
Organs for Excretion and Respiration
Though excretion (typically a digestive process) and respiration are different processes involving two different animal organ systems, the goal is common in that they are both aimed at determining the special organ of use among the animals that were observed.
Type of Locomotion
Answers the question on whether the animals swim, crawl on its belly, walks using its legs, fly, or burrows in a substrate.
Segmentation
The key characteristic to check when it comes to segmentation is the continuity of the subject animal’s body segment. In the case of earthworms, for example, the degree of segmentation is high in that its body exhibits a linear form of continuity, despite the fact that it is also composed of different organ systems just like other animals that were discussed; this is opposed to the lobster that has a skewed form of segmentation.
Appendages
This describes the uniqueness of some body parts that may be found on the animal’s distal or lateral sides, depending on the type of appendage(s) present.
Discussions
Based on the results of the series of laboratory experiments, it can be deducted that different animals, particularly the ones that were observed and monitored in the said lab activities have distinct characteristics. Now, the most important questions that need to be answered would be what the significance of those animals’ specimens having distinct characteristics is. Basically, these characteristics have something to do with the respective animal species' structure or form, and function. Specie worth noting here would be the sponges. Based on the information provided in Table I, which in turn is based on the results and findings of the laboratory experiments, sponges are asymmetrical, either radially and bilaterally. That is, their body form or structure is not uniform. in terms of segmentation, their body form or structure is not composed of any segmentation. Now, there is a reason why they have an asymmetrical body and thsi has something to do with their organ systems. They have a unique body cavity and that is a spongocoel. They also have a unique digestive system and circulatory system (i.e. choanocytes). They have no respiratory and excretory system and their support system is basically their body itself (i.e. spicules embedded in their spongin body). Their characteristics, based on the ones that were observed by the lab researchers, can be rationalized by their structure and function (AAAS 01).
In terms of the crayfish, they are symmetrical bilaterally, just like majority of the animal species observed. Their digestive openings are their mouth proximally and their anus distally. Their body cavity is a coelom plus a pericardium that houses their open circulatory system plus their heart and arteries. The researchers were able to observe that they do not have veins, something that is interesting considering the fact that fishes typically have veins, just like other vertebrates. The purpose of the pericardium is to serve as a cavity, aside from the exoskeleton that houses its open cardiovascular system and its heart as well as its respiratory system which is opened by its gills. Interestingly, the crayfish has the following appendages which are uncommon among other fishes: 10 walking legs, 2 pairs of antennae, telsons, uropods, and swimmerets. In most cases, fishes only have swimmerets which assist it in its aquatic locomotion. Fishes, notably, do not have the ability to walk on water; in teh case of the crayfish, however, they have 10 walking legs as their appendage and this enables them to both walk and swim, not at the same time but simultaneously.
There are of course other specific examples that can prove how an animal's structure and function can be used to rationalize its characteristics. Most body parts or components are not just present for teh sake of being present. They have to have a reason to be there and in this has been the working hypothesis of the author of this paper as he moved forward in each of the laboratory experiments. Skin gills are present in the aquatic animals that were observed because they use them as their respiratory inlet; basically that is how they breathe. In the case of the sea stars, they have dermal branchiae, as shown in the gross inspection that was done during the experiments. These branchiae are essentially a part of the creature's respiratory system because they use it to breath together with the skin gills.
Another example would be the grasshopper, so far, it was the only specimen in the series of laboratory activities that had wings and could fly, although it was essentially a terrestrial animal and can also walk on land and other hard surfaces. It uses its wings to fly and this basically proves the notion that animal structures exist to support or rationalize its form or structure as well as its function. In terms of the flatworms, they have a different body structure or at least the shape of their body cavity especially when compared to the earthworms. Flatworms are based on the name itself, are flat. Earthworms on the other hand are round, yet they share a lot of similar qualities such as their symmetrically and the presence of other body organs and the same goes with those organs' functions.
To summarize, animals can be diverse not just in appearance but also in terms of form and function (Purchon 587). The presence of certain distinct characteristics should not be seen as a peculiarity but rather as a rationale for its function and or structure (Kent University Press 01). The confirmation of this hypothesis has so far been consistently proven by all of the laboratory experiments.
This was one of the primary goals of this experiment and so far it has been accomplished. Animal diversity is essentially a concept that explains that animals have different functions, forms, and structures, as was proven in the laboratory experiments.
Works Cited
AAAS. Animal Diversity. (2016). 01. Print
Purchon, R The biology of Molluska. (2013). 587. Print
Kent University Press. Animal Form and Function. (2016). 01. Print
