AN OVERVIEW OF FUNGI.docx

**Domains of Life** Dr. Carl Woese proposed separating life into three (3) domains: Eukarya, Eubacteria, and Archaebacteria. Domain Eukarya comprises animals, plants, fungi and protists. All members of the domain Eukarya have eukaryotic cells. This means that they have a nucleus and cytoplasmic or...

**Domains of Life** Dr. Carl Woese proposed separating life into three (3) domains: Eukarya, Eubacteria, and Archaebacteria. Domain Eukarya comprises animals, plants, fungi and protists. All members of the domain Eukarya have eukaryotic cells. This means that they have a nucleus and cytoplasmic organelles attached to the membrane (Figure 1). Species in domain archaea and bacteria are all prokaryotic. Prokaryotic cells do not have membrane-bound nucleus and organelles (Figure 1). Archaean, members of domain Archaea, exist in extremely harsh environments. **DOMAIN ARCHAEA** Archaeans are unicellular, prokaryotic organisms. They can be found in a range of habitats ranging from lakes and soil to the Dead Sea to the deepest areas of the ocean, due to their ability to survive harsh conditions. Diversity of Archaeans: Archaeans are abundant in several environments including areas where only few other species can live. Archeans can thrive in extreme environments because they have special proteins and have developed molecular adaptations which allows them to metabolize and reproduce Some archaean species called halophiles (\"salt lovers\") live in very salty areas, such as Utah\'s Great Salt Lake, the Dead Sea, and seawater ponds used to produce salt. Natronomona pharaonis isolated from Lake Zuf in Wadi Natrun Egypt is an example (Figure 2). Another group of archaea, called the thermophiles, which means heat loving, survive in areas with very high temperatures. Some even live near deep-ocean vents, where temperatures are above 100°C, the boiling water point at sea level! An example is the Vulcanisaeta distributa (Figure 3). The organism was isolated in eastern Japan, obtained directly from solfataric fields or piped hot spring water. Other thermophiles survive in acidic environments. Many acidic and hot pools in Yellowstone National Park harbor such archaea, which give the pools a vivid greenish color. The methanogens, which is another group of archaeans, live in anaerobic (lacks oxygen) environments and they produce methane as a waste. Many thrive in solid waste landfills and anaerobic mud at the bottom of lakes and swamps. An example is found in Figure 4, the Methanobacterium thermoautotrophicum. This methanogen was isolated from the Champaign, Illinois, USA municipal waste-treatment facility. The digestive tracts of cattle, deer, and other animals that rely heavily on cellulose for their nutrition are also inhabited by large numbers of methanogens. **DOMAIN EUBACTERIA** Bacteria or Eubacteria are prokaryotic organisms, which lack a nucleus and other membrane-bound organelles. Since they lack these parts, all the process takes place in the cytoplasm. Bacteria may be pathogenic or non-pathogens. Pathogens cause, or can cause diseases. Bacteria can be classified according to: (a) Cell Form, (b) Cell Wall composition, (c) Nutrition mode, and (d) Mode of Respiration. A. Cell Shape The determination of cell type by microscopic analysis is an important step in identifying bacterial organisms. Figure 6 indicates three of the most common forms of bacterial cells Spherical bacterial cells are called cocci. Cocci that are in chains, are called streptococci (Greek word streptos= twisted). Other cocci are in clusters and they are called staphylococci (Greek word staphyle=grapes). Rod-shaped bacteria or bacilli (singular, bacillus) occur singly, in pairs or in chains. Bacillus anthracis as shown in Figure 6 exists in chains. Another type of bacterial cell shape is the spiral. Spiral cells have two types: spirochete and spirillum. Spirochetes' cells are longer and their cell walls are more flexible while spirilla have shorter cells and a more rigid cell wall. B. Mode of Nutrition A bacteria's mode of nutrition depends on how an organism obtains energy and carbon (see Figure 7). Photoautotrophs use sunlight for energy and CO2 as a carbon source. An example is Cyanobacteria. Like plants, cyanobacteria performs photosynthesis and uses chlorophyll a and produces O2 as a byproduct. Photoheterotrophs use sunlight as a source of energy and organic compounds as their carbon sources. This mode of nutrition can only be found in some bacterial species like the purple nonsulfur bacteria. Most of them are present in aquatic sediments like the example shown in Figure 7. Chemoautotrophs extract energy from inorganic chemicals, and produce organic molecules using carbon from CO2. They can thrive in environments that seem totally inhospitable to life like hydrothermal vents, since they need sunlight. These bacterial species use sulphur compounds as an energy source. Chemoheterotrophs are the most diverse and the largest group of prokaryotes. They gain both energy and carbon from organic sources. Almost every organic molecule is food for chemoheterotrophic prokaryote species. C. Mode of Respiration Bacterial species also vary in needs for and responses to oxygen. These differences are important to the ecological or medical roles of microbes. Obligate aerobes require O2 in order to survive. Obligate anaerobes, such as the bacterial Firmicutes genus Clostridium, are poisoned by O2. People suffering from gas gangrene caused by Clostridium perfringens and related species are usually treated by placement in a chamber with a high oxygen content (called a hyperbaric chamber), which kills the organisms and deactivates the toxins Obligate anaerobes, such as the genus Clostridium are poisoned with O2. Persons infected with gas gangrene caused by Clostridium perfringens and related species are typically treated by putting the person in a chamber with high oxygen content (called a hyperbaric chamber) that kills the bacteria and deactivates the toxins. Aerotolerant anaerobes can grow in the presence of oxygen and are not poisoned by it. However, they O2 and do not use oxygen for their growth. These organisms obtain their energy by fermentation or anaerobic respiration. Facultative anaerobes grow in the presence or absence of oxygen. If oxygen is present, they use it for respiration, but they can also obtain energy via anaerobic fermentation, or use inorganic chemical reactions, if O2 is unavailable. D. Cell Wall Composition Nearly all bacteria have a cell wall, a feature that enables them to live in a wide range of environments. The cell wall provides protection and prevents the cell from lysing in a hypotonic environment. The cell walls of bacteria fall into two general types, which scientists can identify with a technique called the Gram stain developed by Hans Christian Gram. This cell wall enables bacteria to survive in different environments. There are two general types of bacterial cell walls which scientists can recognize with a technique developed by Mr. Hans Christian Gram, called the Gram stain Gram-positive bacteria, as seen in Figure 7, have simpler walls with a fairly thick layer of a material called peptidoglycan, a polymer of sugars cross-linked by short polypeptides. Gram-negative bacteria's cell wall on the other hand, have a thin layer of peptidoglycan. It also has an outer membrane that contains lipids which are bonded to carbohydrates. After gram staining, Gram-negative bacteria will have a pink (pink) from Gram-positive (purple) bacteria as shown in Figure 8. Figure 8. Gram positive and Gram negative bacteria (Brooker, Widmaier & Graham, 2016) (a) Streptococcus pneumoniae, stains positive (purple) with the Gram stain. (b) Escherichia coli, stains negative (pink) when the Gram stain procedure is applied. Harmful Effects of Bacteria: 1. Bubonic Plague - causes headache, fever and vomiting. This is a bacterial infection caused by Yersinia pestis. 2. Pneumonia- lung infection caused by either fungi,virus or bacteria. Among adults, bacterial pneumonia is the most common type and is caused by Streptococcus pneumoniae. 3. Tuberculosis- lung infection caused by Mycobacterium tuberculosis. This is an infectious disease that can affect other organs in the body. Benefits of Bacteria: 1. Probiotics- (health promoting bacteria) helps in digestion of food 2. Fermentation- bacteria aids in the fermentation process of food such as cheese and vinegar 3. Antibiotics- bacteria are genetically-engineered to make new antibiotics 4. Decomposers- bacteria degrade organic substances and release in the environment simple molecules that can be used by other living beings. **Domain Eukarya -- Protists** AN OVERVIEW OF PROTISTS Protists are thought to have been the first eukaryotic cell to have existed on the planet. Scientists believe that the very first protist was formed when a unicellular prokaryote and a bacterium it consumed partnered up for survival. Later on, the bacterium transformed into the mitochondrion -- an organelle exclusively found in eukaryotic cells. The diversity of protists is one of the reasons why they, as a group, cannot be distinguished by a few characteristics. The majority of protists are unicellular and microscopic, but some can be multicellular or colonial, which can be as large as trees. Some protists can even be unicellular, colonial, or multicellular at some point in their life! Some protists are autotrophic like plants, while some are heterotrophic and consume other organisms for nutrition. Again, some protists can even be both autotrophic and heterotrophic (called mixotrophic)! Despite their differences, a common feature among protists is that they are aquatic and prefer to live where there is water. This can be virtually anywhere -- in bodies of water such as oceans or lakes, in terrestrial habitats with enough moisture such as damp soil or leaf litter, or even inside the body fluids of living organisms. ANIMAL-LIKE PROTISTS These protists, informally called protozoans (literally, "first animals") are likened to animals because they are generally heterotrophic and most are capable of locomotion. In the past, scientists used to group them according to the cellular structures they use for movement. Some protozoans, particularly amoebas, use pseudopodia to move around and catch organic matter or other smaller organisms. Their pseudopodia are extensions of the cytoplasm of their cells, and the appearance of this structure varies among different groups of amoeba. Amoeba such as Entamoeba histolytica, which causes amebic dysentery in humans, has tube-like pseudopodia. Other organisms that use pseudopodia are tiny organisms called foraminifera, which have thread-like pseudopodia. Their pseudopodia extend through small pores in their shells made of calcium carbonate. When they die, their shells, called tests, often become fossilized in sedimentary rocks. They consume smaller organisms but some species are capable of photosynthesis by "stealing" chloroplasts from organisms it consumed. Meanwhile, some protozoans use flagellum (plural flagella), a whip-like structure attached to their cell, in order to move. The number and appearance of the flagellum also differ across different groups. Notable flagellated organisms include two disease-causing organisms: Giardia lamblia, which causes intestinal diseases in humans, and Trichomonas vaginalis, which causes a sexually-transmitted disease. Some protozoans developed shorter hair-like projections called cilia for movement. Compared to the flagella, these cilia are much smaller and more numerous, usually covering the entirety of the organism. Movement using cilia can be compared to how boats move using oars. A notable ciliated organism is Paramecium, which is known to control populations of organisms in bodies of water by feeding on bacteria or smaller protists. However, not all protozoans are capable of movement. This includes the Plasmodium species, a blood parasite which causes the tropical disease malaria. This organism has a complicated life cycle which involves undergoing different life stages in both the mosquito and their human host. PLANT-LIKE PROTISTS As you might have thought, plant-like protists (which are informally called algae) are usually autotrophic and photosynthetic, much like plants. Interestingly, like plants, some algae such as the dinoflagellates also have the carbohydrate cellulose in their cell walls. These unicellular organisms can also be heterotrophic, and in fact, when there is too much food source, they multiply rapidly, causing the phenomenon known as "red tide". Some algae have silicon dioxide in their cell wall instead, such as the diatoms. This particular substance gives these organisms a glass-like appearance. Most diatoms are photosynthetic but have limited locomotion. Other than being photosynthetic, some algae even closely resemble plants, as in the case of the red algae, brown algae, and green algae. Red and brown algae have different photosynthetic pigments compared to green algae and plants, giving them different colors. These pigments enable them to perform photosynthesis in deep water, where there is less amount of sunlight. Most of these algae are autotrophic and multicellular, (except for green algae, which can also be unicellular). Additionally, flagella can be present in some species of brown and green algae especially in the early stage of their life cycle. Red algae are strictly nonmotile FUNGUS-LIKE PROTISTS These protists are likened to fungi due to being decomposers (feeding on dead organisms) and using spores for reproduction, but are not classified as such due to the absence of chitin in their cell walls. One such organism, the slime mold, is originally unicellular but have been observed by scientists to move (using a cellular structure similar to pseudopodia) and aggregate with others of its kind to seemingly form a single organism, especially when food supply is low. SIGNIFICANCE OF PROTISTS The diversity of protists makes them a widespread focus of study and utility in many fields of science. In some ways, many scientists and other professionals deal with protists every day! ECOLOGY Ecologists specialize in studying the relationships between organisms and their effects to the ecological community they live in. Some species of protists are mutualistic, giving beneficial effects to their partner organism while also receiving positive effects. An example of a mutualistic relationship is between corals and species of algae known as Zooxanthellae. Some protists can use energy from light (or inorganic chemicals) to convert carbon dioxide to organic compounds, as in the case of photosynthetic protists. In fact, most of the Earth's oxygen are produced by organisms in the ocean, including photosynthetic protists such as algae. Additionally, these autotrophic organisms, called producers, form the base of food webs in their ecological community. Larger organisms in aquatic communities rely on protists (from as small as plankton or as large as seaweed or kelp) for food, while even larger organisms consume those who have eaten a producer. As a result, factors that negatively impact the population of protists can also negatively affect the organisms that depend on them. However, an increase in the population of some algal species may not be beneficial and needs to be controlled. When nutrients are more than enough, the algae population explodes and algal blooms happen. Algal blooms can occur in bodies of water where there is an increase in phosphorus and nitrogen, which are usually fertilizer runoffs, causing a bloom of green algae. (You can see them as green discoloration or scum that floats in ponds or other bodies of water.) The existence of an excessive population of algae depletes oxygen in the area, which makes it impossible for other aquatic life to survive. Additionally, algal blooms of dinoflagellates cause the phenomenon "red tide", which not only robs off oxygen but also spreads deadly toxins. These toxins may be passed down to the organisms which consumed these protists, such as fishes and shellfishes. MEDICAL FIELD Not all relationships formed by protists are beneficial to other organisms. As you have seen, many protists live as parasites and cause harm and disease to humans and other organisms. Many years ago, malaria, a disease caused by Plasmodium, ravaged countries in the tropics and overall had negative impacts on public health and national economy. Giardia and Entamoeba cause intestinal diseases in infected persons, while Trichomonas is a prevalent sexually-transmitted pathogen. FOOD TECHNOLOGY Some substances derived from protists have been added to human food for years. Seaweeds have been farmed for human consumption. Sushi wrapper, also known as nori, is derived from dried sheets of red algae. Furthermore, substances derived from seaweeds such as carrageenan are used as thickeners and food preservation of ice cream and yoghurt. **Domain Eukarya -- Fungi** In the past, scientists were confused on how to classify fungi. Since they were eukaryotic organisms which are nonmotile and grow from the ground, they were simply classified as "non-photosynthetic plants". However, they were not plants at all. Fungi get their nutrition by delivering powerful enzymes outside their bodies that digest organic matter near them. For some fungi, this organic matter may be dead organisms, while for some, this may be living hosts. As time went by, scientists recognized that fungi were more closely related to animals than plants. One of the defining characteristics of fungal cells is the presence of chitin in their cell wall, a substance also seen in insect exoskeletons and fish scales. The presence of chitin is one of several features which relate fungi to animals. Fungal organisms can be unicellular or multicellular. Fungi that live most of their lives as unicellular organisms are commonly known as yeasts. Conversely, multicellular fungi can grow much larger. In these multicellular fungi, such as mushrooms and molds, their cells form into long, slender branching filaments called hyphae. What is unique in the hyphae is that in most fungi, a boundary between the cells is not virtually present. The hyphae virtually comprise the entirety of a multicellular fungus and can form different structures. What you recognize when you see a mushroom -- and what you use in identifying the mushroom -- is actually the fruiting body of the fungus, which is its reproductive structure, formed from the hyphae. However, this is the only visible part of the fungus. More of the hyphae branch out underground and form the mycelium, which serves to absorb nutrients. In soil fungi, the mycelium can extend more than 2 meters into the ground. Clusters of mushroom, which is the fruiting body, that you see on the ground may be a part of the same mycelium, and can actually be a part of the same organism. Some mycelia can grow very large and live for many years without humans noticing. In fact, strangely enough, the largest living organism on the planet just might be a fungus! Armillaria ostoyae, known as the honey fungus, is measured by scientists to be stretched out for 3.8 kilometers in the Blue Mountains in Oregon, United States, and is estimated to be thousands of years old. Fruiting bodies are commonly found at the edges of the mycelium, which usually form rings on the ground. Many years ago, some cultures believed that these rings of mushrooms indicated where fairies danced in circles the night before, earning them the name "fairy rings". THINK ABOUT IT What benefits could the fungi have by growing its fruiting bodies on the edge and not at the center? The reproduction of fungi can be asexual or sexual. Asexual reproduction in fungi involves the release of spores which can travel through air and water and are resistant to harsh conditions. A specific group of fungi has spores with flagellum (which again relates them to animals), but most spores are nonmotile. Some fungi also reproduce asexually by simply breaking off a hypha or through budding, where a part of the cell bulges out to form a bud and eventually separates to form another cell. Meanwhile, sexual reproduction involves two different gametes, but instead of being described as "male" and "female", they are denoted as "+" and "-". GROUPS OF FUNGI CHYTRIDS Fungi belonging to this group are unique in that they are the only fungal species that have flagellated spores, called zoospores. Some chytrids are unicellular, while some can form colonies with hyphae. They are ubiquitous in lakes and in soil. Like any other groups of fungi, some species are decomposers, while some are mutualists, helping some herbivores to digest plant matter. Furthermore, some are parasitic, and scientists believe that one such organism led to the decline of frogs and other amphibians in recent years! Batrachochytrium dendrobatidis causes skin infection in these animals and may lead to death -- and even extinction -- of an entire population of amphibians. ZYGOMYCETES You may have noticed molds growing on leftover bread or fruits you have neglected to put away. Some can even grow on walls and ceilings. The color of molds can vary, but one common characteristic among molds is that they form a carpet-like surface wherever they grow. They owe this appearance to the numerous upright hyphae which hold their pigmented spores, called the sporangium. Other than molds, this group also include fungi which live as parasites or as commensal symbionts of animals. In summary: ▪ Fungi are important in the ecosystem because they are primarily decomposers and feed on dead organisms, allowing the recycling of nutrients. ▪ Some fungi acquire nutrition by forming mutualistic relationships with plants and animals. ▪ Fungi are composed of hyphae which form other structures such as fruiting bodies and mycelia GLOMEROMYCETES Most fungi belonging to this group form a mutualistic relationship with plant roots. This symbiotic association of plant roots and fungi are called mycorrhizae. Notable mycorrhizal fungi include species of the genus Glomus. Mycorrhizae can form a very complex network of fungal mycelia attached to the roots of plants, increasing the effective area of the root system in absorbing water and minerals. In turn, the plants provide the fungi with the products of photosynthesis. This partnership has been known by scientists for years, but now it has been estimated that 80 to 90 percent of all plant species form mycorrhizae with fungi. Aside from bringing in nutrition, the mycorrhizae also enables plants to communicate, and can even be essential for their survival! ASCOMYCETES This group is rightfully named as sac fungi because they produce spores, called ascospores, in sac-like microscopic or macroscopic fruiting bodies called asci. Although some have even adapted into marine or freshwater habitats, most of the known species are terrestrial. These terrestrial fungi can either be pathogens, parasitic (including Cordyceps), plant decomposers, or form mutualistic relationships (called lichens) with a photosynthetic partner, which are usually green algae or cyanobacteria or both. In lichens, photosynthesis carried out by the other organism provides nutrition for the fungus. Meanwhile, the densely packed fungus absorbs water and minerals, and can even provide protection for the delicate cells of its partner! Lichens can grow in very harsh environments, such as on dry rocks in deserts or on the tops of mountains. Another notable organism in this group is the yeast Candida albicans. It is usually a commensal organism in humans, but can cause diseases when an individual's immune system becomes compromised or when nutrition is high, as in the case of diabetic patients when blood glucose is high. Diseases caused by C. albicans include vaginal yeast infection and infections of the mouth called thrush. BASIDIOMYCETES Spores of fungi in this group are produced and held by a club-shaped structure called basidium, giving this group the name club fungus. Fungi included in this group include the mushrooms that you eat! The largest living organism, the honey mushroom, also belongs in this group. Puffballs, fungi known to emit spores in a cloud of dust-like spores, are also included in this group. Some species also cause plant diseases, but some are important decomposers of wood and other plant material such as the shelf fungi. DEUTEROMYCETES Also known as the imperfect fungi, this is an informal grouping which is composed of fungi which have no known sexual form of reproduction and those that do not fit into other groups. The first ever known antibiotic, penicillin, was discovered by Sir Alexander Flemming in 1928 from one of these fungi, Penicillium rubrum. SIGNIFICANCE OF FUNGI Many fields and careers in science have involved the research and utility of fungi. Fungi may be closer and more familiar than what you have expected! ECOLOGY Ecologists study the interrelationships between organisms and their environment, including fungi. For example, some fungi form mutualistic relationships with plants (as in the case of mycorrhizae and lichens), making farming more productive. Some also partner up with animals, such as in leaf-cutting ants in tropical forests which rely on fungi to help them digest leaves. Meanwhile, some fungi live as parasites of plants (causing events such as crop blights) or animals (as in the case of Batrachochytrium dendrobatidis which decimated amphibian populations). However, the most significant role of fungi is that of being decomposers. Most fungi play a key role in ecological interactions because they are well adapted as decomposers of organic materials, bringing important nutrients back into the soil for the growth of plants, and in turn, the animals that eat these plants. MEDICAL MYCOLOGY Medical mycologists are scientists who specialize in the study of human diseases caused by fungi. The general term for an infection in humans and animals by a fungal parasite is mycosis. Notable mycoses include skin diseases such as ringworm, athlete's foot, and vaginal and oral thrush. Additionally, with the emerging studies on infections in individuals with compromised immune system (as in the case of AIDS or cancer), many fungi which do not normally cause diseases have been recently given medical significance. FOOD TECHNOLOGY Despite the many dangers posed by fungi, their significance, particularly in food technology, cannot be ignored. For thousands of years, humans have employed yeast in the production of alcoholic beverages through fermentation, as a leavening agent in making bread, and as ripening agents in some types of cheese. Additionally, mushrooms have been of human interest for consumption, and some are even treated as highly prized delicacy for their complex flavors, such as morels and truffles. PHARMACOLOGY Pharmacologists specialize in creating and developing new medications, which requires them to research and study chemical interactions that take place between living organisms and different compounds. Aside from penicillin, many drugs have been derived from fungi including cholesterol-lowering drugs and cyclosporine, which is used by organ transplant patients. Lysergic acid diethylamide (LSD), a hallucinogenic drug, is derived from substances produced by a fungus which grows on rye RESEARCH An ascomycete, the yeast Saccharomyces cerevisiae, is easy to culture and to manipulate, a reason why scientists use it in studying the molecular genetics of eukaryotes. This research particularly benefits the study of genetic disorders such as Parkinson's disease. S. cerevisiae is also used by scientists as a host for genetic modification on which they make strains of the organism capable of producing biological compounds such as insulin-like growth factor, helping individuals with medical conditions that prevent them from producing these substances. Another ascomycete, Gliocladium roseum, can grow on wood or agricultural waste and produce hydrocarbons (such as those found in diesel fuel). Scientists are studying how this fungus can produce hydrocarbons and are hoping to replicate the metabolic pathways involved In summary: ▪ Different groups of fungi differ in the appearance of reproductive structures. ▪ Some fungi acquire nutrition by forming mutualistic relationships with plants and animals. ▪ Parasitic fungi can cause a variety of infections in humans, animals and plants. ▪ Aside from being used as food, fungi have uses in the pharmaceutical and research industry FORMATIVE ASSESSMENT 1. Supply the missing words to complete the overview on the cellular structure of fungi. Fungi are eukaryotic organisms characterized by having 1) \_\_\_\_\_\_\_\_\_\_ in their cell wall. They can be unicellular, called 2) \_\_\_\_\_\_\_\_\_\_, or multicellular, forming long threads called 3) \_\_\_\_\_\_\_\_\_\_. This threads can form visible reproductive structures called 4) \_\_\_\_\_\_\_\_\_\_ and complex networks called 5) \_\_\_\_\_\_\_\_\_\_ which absorb nutrients. GRADED FORMATIVE ASSESSMENT 1 A. TRUE OR FALSE. Write TRUE if the statement is correct; otherwise, write FALSE. 1. Most fungi acquire their nutrition by photosynthesis 2. Clusters of fruiting bodies are more likely to be part of a single fungal organism. 3. Fruiting bodies are usually found at the edges of th mycelial network. 4. Chytrids are known to have nonmotile spores. 5. Zygomycetes usually form carpet-like surfaces wherever they grow. B. IDENTIFICATION. Identify the term being described. \_\_\_\_\_\_\_\_\_\_\_\_1. This is the ecological role of most fungi in the environment. \_\_\_\_\_\_\_\_\_\_\_\_2. This refers to a form of fungal reproduction wherein a part of the cell bulges out and eventually becomes a separate cell. \_3. These spores are known to be unique among fungi for being flagellated. \_\_\_\_\_\_\_\_\_\_\_\_4. This organism is known to have decimated several amphibian populations by spreading deadly skin infections. \_\_\_\_\_\_\_\_\_\_\_\_5. This upright structure in Zygomycetes holds their spores. FORMATIVE ASSESSMENT 1: Analogy. Study the first pair of words and decide how the two words relate to each other. Then, supply the missing word/s so that the second pair of words has the same relationship. 1. mycorrhizae : plant :: lichens : \_\_\_\_\_\_\_\_\_\_ 2. sac-like : asci :: club-shaped : \_\_\_\_\_\_\_\_\_\_ 3. B. dendrobatidis : skin infection :: C. albicans : \_\_\_\_\_\_\_\_\_\_ 4. yeast : leavening agent :: P. rubrum : \_\_\_\_\_\_\_\_\_\_ 5. cup fungi : Ascomycetes :: shelf fungi : \_\_\_\_\_\_\_\_\_\_ FORMATIVE ASSESSMENT 2 Open Response. Answer the following concisely. 1. Enumerate at least 3 common characteristics of fungal organisms. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 2. Give at least 2 features that relate fungi to animals aside from being eukaryotes. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 3. Give one identifying characteristics of protists found in the following groups: a. Chytrids \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ b. Zygomycetes \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ c. Glomeromycetes \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ d. Ascomycetes \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ e. Basidiomycetes \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ f. Deuteromycetes \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ GRADED FORMATIVE ASSESSMENT 1: Matching Type. Match the description in Set A with the corresponding organism in Set B. Write the letter of your choice before each number (1 point each). Each letter can only be used once. Then, match the organism in Set B with its corresponding classification in Set C. Write the Roman numeral of your choice after each letter (1 point each). Each Roman numeral can be used once or several times. SET B: ORGANISM A. shelf fungi D. Gliocladium roseum B. Candida albicans E. Saccharomyces cerevisiae C. Penicillium rubrum F. Batrachochytrium dendrobatidis SET C: CLASSIFICATION I. Ascomycetes III. Deuteromycetes II. Basidiomycetes IV. Glomeromycetes SET B SET C SET A: DESCRIPTION 1. This fungus is being studied as a potential source of biofuels. 2. The first antibiotic drug was manufactured from this fungus. 3. This fungus is an important decomposer and grows as stacks on trees. 4. This yeast has prominent uses in the fermentation process and in the molecular genetics research of eukaryotes. 5. This fungus is known to cause diseases, such as vaginal yeast infection and oral thrush, in humans with compromised immune system. **Domain Eukarya -- Plants** Photosynthesis is the sole biochemical pathway that can convert energy from the sun to a form of energy that every organism uses for its metabolic needs. In general, plants are multicellular and autotrophic eukaryotes that obtain energy through photosynthesis. They are said to be autotrophic because they have chlorophyll -- the green pigment responsible for absorbing light energy that enables them to photosynthesize. Thus, they are fondly described as "stationary animals that eat sunlight". They serve as the base of the food chain in every terrestrial ecosystem. Also, their cells are protected by cell walls made of cellulose, a complex form of carbohydrate. The land plants that we are familiar with today are believed to have evolved from a freshwater environment 400 million years ago. Their successful colonization of the terrestrial environment brought about the proliferation of diverse groups of organisms nowadays. What were the challenges they faced in a terrestrial ecosystem and how did they adapt to these challenges? To live in a terrestrial ecosystem, there were several major problems to solve: \(1) How to get nutrients out of bare rock? An intimate, mutual association between plant roots and fungi paved the way for terrestrial survival. This association called mycorrhiza (meaning "fungus roots") helps plants absorb phosphorus and other nutrients they need as fungi release them from rocks, and in return, the sugars produced by plants nourish the fungi. In nature, nearly all plants have mycorrhizae. In fact, mycorrhizae appear in fossils of the oldest known plants, suggesting the importance of this relationship in plant adaptation to land. \(2) How to transport nutrients from the soil and products of photosynthesis to other parts of the plant body? Almost 90 percent of plants have vascular tissue, a network of cells joined into narrow tubes that extend throughout the plant body. The plant's vascular tissue has two types - xylem which conducts water and minerals up from the roots; and phloem which distributes sugars throughout the plant. \(3) How to minimize water loss? Helping plants to retain water is a waxy cuticle that covers their aerial parts, the stems and leaves. Although this waxy cuticle prevents the efficient exchange of gases in plants, there are stomata present on leaf surfaces that help facilitate the diffusion of oxygen and carbon dioxide gases. \(4) How to reproduce without a water medium? To be able to live on land, plants must keep their gametes (sex cells - the egg and sperm) and developing embryo from drying out. Thus, most plants produce gametes in gametangia, the structures that consist of protective jackets of cells surrounding the gamete-producing cells. The egg remains in the female gametangium until it is fertilized there. Once fertilized, the embryo develops attached to and nourished by the parent plant. Demands of land environment led to cell differentiation, in which each cell assumes a role, and thus develop into a specific plant tissue or organ. The body of a land plant is partly below ground, in soil, and partly above ground, in air. A plant must be able to hold itself upright because air provides no support. Roots anchor them to the ground and absorb water and nutrients from the soil. The elongation and branching of a plant's roots and stems maximize its exposure to the resources in soil and in air. Upright stems and leaves require structural support, and this is provided by the rigid cell walls of plant tissues. The stem connects the plant's subterranean and aerial parts, conducting water and minerals upwards and transporting the products of photosynthesis from the leaves to the different parts of the plant body. The leaves of plants display adaptations shaped by the need to gather sunlight. Most plants in our country, being in a tropical rainforest biome, have broad leaves or large surface area to maximize the amount of light absorbed. Also, the leaves have drip tips which enable rain drops to run off quickly. Plants need to shed water to avoid growth of fungus and bacteria in the warm, wet tropical rainforest. The adaptations of other plants in different biomes, like in a desert, are also different from other biomes. Plant reproduction occurs through an alternation of generations, in which the life cycle alternates between a haploid stage called a gametophyte and a diploid stage called a sporophyte stage. (Haploid cells contain a single set of chromosomes, whereas diploid cells contain two sets of chromosomes.) Ninety percent of plant species on Earth have dominant sporophyte structure that is visible to the eye, while the gametophyte structure remains dependent and inconspicuous. Figure 3 below shows the alternation of generations in fern In summary: Plants are multicellular and autotrophic eukaryotes that have cell walls made of cellulose. To successfully colonize lands, they developed special tissues and organs like roots, stems and vascular bundles, and leaves. Other important features include the waxy cuticle and the stomata. To cut their dependency on water during fertilization, they have developed gametangia which keep the gametes and developing embryo from drying out. Plant reproduction occurs through an alternation of generations Overview of the Plant Kingdom The dichotomous key above already gave you an idea how plants are classified. There are two major groups of plants -- those that do not have vascular bundles, the bryophytes; and those with vascular bundles, the tracheophytes. Adaptations further divided the tracheophytes into two - those which reproduce through spores like ferns, and those that reproduce through seeds, the gymnosperm and angiosperms. The cladogram below shows the evolutionary adaptations among the various groups of plants. Mosses and their relatives Bryophytes or nonvascular plants include mosses and their relatives. Unlike all other plants, they do not have specialized tissues (xylem and phloem) that conduct water and nutrients. Instead, every part of a moss obtains water directly from the environment through diffusion. Because of this, mosses and their relatives can only live in moist habitats like shady parts of the forests, rocks on a river. In the Philippines, they thrive during the wet season Mosses are unique among plants in that the gametophyte is much dominant than the sporophyte stage. The mosses you see attached on the wall, the pathways or on the forest floor is the haploid gametophyte. When you look closely, the "head-like" structures are the tiny, diploid sporophyte. In most mosses, the male and female gametophyte are separate. For fertilization to occur, the sperms from the male gametophyte are directly released into the environment and must swim to the female gametophyte to fertilize the egg. This is one reason why mosses can only survive in moist habitat, they are dependent on water for reproduction. Upon fertilization, the newly developed sporophyte is dependent on the female gametophyte for nutrition until such time that the cells can undergo meiosis to produce haploid spores that scatter and grow into new gametophytes or new moss plants. Most moss spores have a tough outer covering that allows them to survive under difficult conditions for some time until it's wet season again. Mosses share these characteristics with their relatives like the liverworts and the hornworts. Ferns and their relatives -- the seedless, vascular plants Ferns and their relatives are seedless plants with distinctive feathery leaves. Unlike mosses, ferns have a vascular system (stems that contain xylem and phloem) for conducting water and nutrients. However, just like mosses, ferns are dependent on water for their reproduction. Thus, they can only survive in moist habitats as well. In ferns, the diploid sporophyte is much larger than the haploid gametophyte. When you see a fern, you are looking at a diploid sporophyte. Mature fern sporophytes form haploid spores on the underside of special leaves called fronds. The relatives of ferns include the club mosses and horsetails below. The Seed Plants - Gymnosperms and Angiosperm Seed plants are the largest group of plants by far. Two key features of the seed plant life cycle have made these plants successful in a wide variety of land habitats -- pollen and seeds. Pollen consists of many tiny grains, each of which is a male gametophyte wrapped in a protective coating. Pollen can be transported to female gametophytes by wind, animals and many other agents. Because the sperm of seed plants do not need to swim to fertilize the egg, they are not restricted to live in moist environments. Another key feature is the development of seeds. The fertilized eggs of seed plants grow into small embryonic sporophytes that are encased in a tough outer coating along with a food supply -- this entire structure is a seed. Seeds can survive in a dormant state until environmental conditions are appropriate for growth. This is why many seed plants do not sprout until you water or plant them in soil. All the seed plants you see are diploid sporophytes. The haploid gametophytes are small and completely dependent on the sporophyte for protection and survival. Gymnosperms -- the cone bearers The most ancient surviving seed plants are the gymnosperm. These plants all reproduce with seeds that are exposed (Gymnosperm literally means "naked seeds".) The most common member of this group are the conifers which include pine trees. Conifers have waxy, needle-like leaves and reproductive structures called cones. Male cones release pollen and then wind carries the pollen to female cones. Because wind blows pollen all over the place, conifers make large amounts of pollen to increase the chance of reaching the female cones. Fertilization occurs in the female cones, which eventually drop the mature seeds for growth. Angiosperms - the flowering plants The flowering plants are the largest and most successful group of seed plants. They have two important features that are absent in gymnosperms -- flowers and fruits. A flower functions in reproduction -- it contains the male structures (the stamen) that produce pollen and the female structures (the pistil) that produce the eggs. In many flowering plants, insects or other animals transport pollen from one flower to another, a process called pollination. The petals, scent and nectar have evolved to attract specific pollinators. This method of pollination is much more efficient than the wind pollination in gymnosperms Flowering plants surround their seed with a structure called fruit -- an adaptation for spreading seeds. Tasty fruits evolved in certain plants so animals are more likely to eat them. In this way, seeds can travel far from the parent plant. The diversity of angiosperms ranges from monocots to dicots; woody and herbaceous plants; and annuals, biennials, and perennials. Keep in mind that the categories can overlap. For example, the daisy (photo on page 1) is considered a perennial, herbaceous dicot angiosperm. GRADED FORMATIVE ASSESSMENT: Answer the following questions. Encircle your final answer. 1. Which of the following characteristics is NOT always present to all plants? A. cellulose cell wall B. mycorrhizal association C. eukaryotic and autotrophic cells D. gametophyte and sporophyte structures 2. Which vascular tissue is responsible for transporting products of photosynthesis throughout the plant body? A. bark B. phloem C. stem D. xylem 3. Mycorrhiza is a beneficial relationship between plant roots and fungi. This symbiotic relationship is also known as \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. 4. In which stage in alternation of generation is pollination part of? \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 5. Identify one of the challenges faced by plants living in the desert and explain how plants overcome this challenge. GRADED FORMATIVE ASSESSMENT Encircle the letter of the best answer in each question. 1. The development of vascular bundles helps plants adapt in land environments. Which of the following are vascular plants? A. ferns B. giant kelps C. liverworts D. mosses 2. The reproductive mechanism of ferns and mosses includes which structures? A. flowers B. fruits C. seeds D. spores 3. Gymnosperms produce neither flower nor fruit because they do not possess which structure? A. embryo B. ovary C. ovule D. seed 4. Based on the dichotomous key below, which is incorrect? 1 1' Does it have a vascular (xylem and phloem) system? If yes, go to 2. Does it have a vascular system? If no, it\'s a moss 2 2' Does it reproduce through seeds? If yes, go to 3. Does it reproduce through spores? If yes, it\'s a fern. 3 3' Is its seed enclosed in a flower? If yes, it\'s the daisy, angiosperm Is its seed \"naked\"? If yes, it\'s a conifer, gymnosperm. A. Bryophytes do not have xylem or phloem. B. Ferns are vascular plants that reproduce through seeds. C. Angiosperms are vascular plants that produce seeds in flowers. D. Plants with xylem and phloem include ferns, conifers, and daisies 5. In angiosperms, the mature seed is surrounded by a \_\_\_. A. cone B. cotyledon C. flower D. fruit **Domain Eukarya -- Animals** Animals are multicellular, heterotrophic, eukaryotic organisms that neither have a cell wall nor chloroplast. Also, they are characterized by the possession of: \(i) body symmetry: symmetry may be either radial (have body parts that extend from a central point) or bilateral (have distinct anterior and posterior ends and right and left sides), however some animals are asymmetrical (irregular symmetry); \(ii) cephalization: bilateral animals develop a head where sense organs and nerve cells are concentrated more than in any part of their body. Cephalization provides advantage to the animal to feel ahead of the possible danger in the surrounding. However, other animals exhibit no cephalic presentation; \(iii) body cavity: There are animals that develop space between the body wall and the intestinal wall. The space serves as protection for the internal organs of the more complex animals. Animals with no body cavity are acoelomate, those with body cavity fully covered by connective tissues such as blood, muscles and bones are called coelomate, while those with body cavity partially covered by connective tissues are called pseudocoelomate \(iv) sex determination: organisms can either be dioecious (sexes are separate) or monoecious (hermaphrodite or one organism possesses two sexes); \(v) skeleton types: animals have three main kinds of skeletal systems: hydrostatic skeletons (composed of soft tissue filled with an incompressible fluid held in a gastrovascular cavity that can change the animal's body shape through the contractile cells in its body wall), exoskeletons (external skeleton that protects the outer surface of an organism) and endoskeletons (skeleton found within the interior of the body; gives structural support and protection support and protection for the internal organs); \(vi) animal habit/responses can either be sessile (immobile) or mobile (motility). Invertebrates are animals that lack a backbone. They vary in size raging from the smallest one, rotifer to giant squids. The majority of animal species are invertebrates, accounting for more than 99%. They occupy a wide variety of habitats, from the grains of sand (terrestrial) to extremely acidic water (aquatic). Clearly, more invertebrates species are still to be discovered, but only few of those already described have been studied in depth. Phylum Porifera ("pori" = pores, "fera" = bearers) Animals under this phylum are also called sponges. They are asymmetrical, acoelomate, sessile animals but larvae are able to swim. They can be dioecious or monoecious, reproduce either asexually and sexually and fertilize either internally or externally. Also, they are mostly marine with no cephalization. They have a skeleton called spicules that can be made from silica, calcium carbonate or protein. Water passing through pores enters a cavity called the spongocoel and then ows out through an opening, the osculum (Figure 3). They have flagellated cells (choanocytes, collar cells) that ingest bacteria and tiny food particles. The amoebocytes are cells in the sponge body that can assume the roles as digestive cells, reproductive cells or structural cells. Sponges are considered the most primitive group of animals because of lack of true tissues. An extraordinary trait of sponges is their ability to filter. They can remove a high percentage of bacteria and particles from the water as well as a high percentage of dissolved organic carbon. These can then be turned into foods for other animals. Aside from these, they also play a role for the recirculation of carbon, silicon, and nitrogen and are the leading contributors of marine bioactive compounds. Phylum Cnidaria (\"cnidos\" = stinging nettle) Cnidarians have unique stinging cells called the cnidocytes that are used to stun its prey with neurotoxin that paralyzes the victim. The group is composed mostly of diversified marine animals of both sessile and motile forms. They are acoelomate; and radially symmetrical. They have no cephalic representation, though they have net of nerves all over the body. The body also has one opening which serves as mouth and anus, called the gastrovascular cavity. They have an internal cavity used for respiration and a gastrovascular cavity (digestive compartment with a single opening). Their skeleton is hydrostatic allowing these animals to have flexible bodies. Two major body forms among the Cnidaria exist - the polyp (sea anemones and corals) and the medusa (jellyfish) (Figure 4). The former has a sessile life cycle and tubular in shape with the mouth facing the water upwards while the latter is mobile and presents a bell- shape with the mouth facing the water downwards. The phylum Cnidaria is divided into four major groups. The first group includes the hydras, Portugese man-of-war, and fire corals which have both types of body forms, the polyp and medusa. The second group refers to the true jellyfishes that have predominant medusa body form. The third group comprises the dangerous box-jellyfishes, which have box-shaped medusa form. The soft and hard corals and the sea anemone belong to the fourth group which occur only in polyp form. They play vital roles to the environment and to human beings. We know that coral reefs provide home to many marine organisms and approximately one million people live on coral islands made of the skeletal remains of corals. Phylum Platyhelminthes (platy = flat and helminth = worm) The soft-bodied invertebrates include tapeworms, planarians, and ukes that are cephalic and bilaterally symmetrical. They are acoelomates thus they do not have a body cavity. Their body is dorsoventrally (extending from back to the belly) flattened with no segments. There is no circulatory or respiratory system which has something to do with their flat body structures because there is limitation with the oxygen and nutrients that pass through their bodies. In addition, they have a simple nervous system with a bundle of nervous tissue. They are often found living free in marine, freshwater, moist or damp terrestrial habitats. However, there are two flatworm classes that have parasitic members: the flukes in class Trematoda and the tapeworms in class Cestoda. Flat worms can be carnivores or scavengers. Planarians (Class Turbellaria) act as invertebrate bioindicators in freshwater environmental quality and other changes in their habitat. They play a vital role in the food chains, as they form the base or as consumer. As producers, turbellarians and flatworms are food sources for amphibians (toads), fish, crustaceans (water bugs). As consumers, flatworms regulate and control the populations of some animals such as protozoan and algae. Turbellarians also are great predators to small invertebrates Phylum Nematoda Organisms under this phylum are commonly called as roundworms indicating their cylindrical shape bodies. They have elongated and unsegmented bodies that are tapered at both ends. They possess a pseudocoelom and are bilaterally symmetrical. Their body wall is covered by a tough cuticle. A part of their muscle has longitudinal muscle fibers, responsible for their trashing movement. They don't have a circulatory system but have an alimentary canal. They reproduced sexually and mostly are dioecious (sexes are separate), with females bigger than males (Figure 1). The worms also exhibit some degree of cephalization with nerves that run throughout the length of the body. They are ubiquitous, inhabiting a diverse and broad range of environments from terrestrial to aquatic. They are composed of both parasitic (on plants, vertebrate, and other invertebrates) and free-living species (found almost in all natural environments). Two examples of parasitic nematodes are Ascaris lumbricoides and Trichinella spiralis. The former is a common and prevalent parasitic roundworm infecting humans and the latter is a notorious nematode causing trichinosis in rodents, pigs, bears, hyenas and even in humans. Soil nematodes do not parasitize plants; rather they are useful in the decomposition of organic matter, in the food web (soil). Thus, they can be an instrument for ecological hypothesis testing and understanding biological mechanisms in soil. Phylum Mollusca Their three main body parts are the visceral mass, muscular foot, and mantle. Most of them are unsegmented and bilaterally symmetrical (gastropods bodies are asymmetrical). They are cephalic and coelomate. Their body (hard shell) is covered by a mantle made up of calcium carbonate. They are dioecious but some are monoecious. In fact, sex change in the Mollusca is almost exclusively protandric (changing from male to female as it grows), and has only been reported among gastropods and bivalves. Most mollusks have complete body systems such as a pair of kidneys and a simple yet complete digestive tract. Members of the phylum exhibit a circulatory system that varies from an open system (majority) to a closed system (Cephalopods). In an open circulatory system, the blood (open and fills the body rather than being stamped in the arteries and veins) is pumped into the hemocoel. A hemocoel is a body cavity that contains blood (hemolymph). The blood from the hemocoel returns back to the heart through an opening called ostia (Figure 2). In a closed circulatory system, the blood is confined in the blood vessel and flows in a single direction from the heart then goes back to the heart, once more. It is a predominant phylum in marine environments although some are freshwater and terrestrial inhabitants. They vary in size from giant squids and clams to little snails. Why are these animals belonging to the same phylum, and yet, are different-looking? One answer lies in the behaviour of their larvae, or immature eggs. The molluscan classes with highest species diversity are those which may have planktotrophic larval development meaning their larvae feed on plankton in order to undergo metamorphosis which contributes to their morphological (form and structure) diversity. Economically, arthropods (gastropods and bivalves) are widely cultivated. Ecologically, they benefit the aquatic bottom environments by providing a home, shelter, and foods to various species. Species of bivalves act as filters aiding in refining the marine waters. Phylum Annelida ("annelus" = little ring) The members of this phylum live in marine, freshwater and, terrestrial habitats. It is a diverse group of animals in terms of forms and structures. Contrary to Platyhelmintes and Nematoda, members of Annelida have segments (their body is made up of a number of repeating units, called metameres) with most of them having bristles called setae (Figure 3). Aside from being referred to as segmented worms, they are described as elongated, cephalic, bilaterally symmetrical, coelomate, and monoecious. In addition, they have a cephalization, an alimentary canal, a closed type blood vascular system, a nervous system, and receptor organs. Members of the phylum include earthworms, leeches, and lugworms. Earthworms act as decomposers (eating organic material) and fertilizers. They also aerate the soil by digging tunnels. Leeches are considered parasites but medicinally they are used to recruit blood flow or reduce blood from a restricted part of the body. There are also some species of water based annelids useful for marine environmental monitoring. Phylum Arthropoda ("árthron" = joint, and "pous" = foot or leg, which together mean \"jointed legs\") Arthropods have an exoskeleton made of chitin and protein. There is body segmentation and cephalization indicating highly developed sense organs. The members also have a bilateral symmetry, true coelom, and an open circulatory system Arthropoda, considered as the biggest and successful animal phylum has an enormous number of described species in a diverse forms and environments. Integrated evidences showed that living arthropods consisted of four major ancestries: chelicerates (spiders, mites, horseshoe crabs, scorpions); hexapods (insects such as ants, dragonflies, butterflies, and cockroaches; and wingless relatives such as the springtails and bristletails); myriapods (centipedes and millipedes); and crustaceans (crabs, crayfish, lobsters, shrimps, barnacles, krill). The insect group alone accounts for 80% of all arthropods Arthropods are vital constituents of ecosystems as they occupy important spots in the food chain and food web, acting as herbivores, predators, and decomposers. Most of them live within the soil thus are involved in the soil development and in upkeeping the soil fertility. Insects are fundamental pollinators of different flowering plants. They are also good ecological indicators of environmental stress and diversity Phylum Echinodermata ("echinos" = spiny and "dermos" = "skin") Some members of the phylum include starfish, sand dollars, sea stars, sea urchins, sea cucumber, and brittle stars. They are coelomates, with larvae as bilaterally symmetrical and adults as pentaradial (five-part) symmetrical (Figure 4). They lack a head and brain (absent as adults). They have endoskeleton but they don't have circulatory, respiratory, or excretory systems. Also, they exhibit a unique water-vascular system. This system is composed of canals that link several suction-cuplike structures called tube feets, which functions in locomotion, food and waste transportation and breathing. In addition, they are dioecious, with no obvious external difference between males and females Regarding the body symmetry, sea cucumbers might be an exemption as they don't look much like an echinoderm. But, they exhibit radial (ve rows of tube feet for moving and feeding) and bilateral symmetry, longitudinally and transversely, respectively. Echinodermata is regarded as a successful and ancient phylum of Animal Kingdom consisting of an estimated 7000 living species and 13 000 extinct species. It has been shown that echinoderms form a great diversity in the bottom of the ocean thus indicating its strong relationship in terms of functions with the coral reefs. With this, they are considered as good indicators of monitoring the conditions of coralline communities. Many are keystone species, extremely high impact maintaining the relationship and structure of the ecosystem. They are carnivores, basis of foods and are primary consumers (e.g. sediments, algae). As we went through the different phyla of invertebrates, we had learned to appreciate the diversity of animal life on Earth. Their different characteristics have allowed them to cope up in their own environment. Whilst most of them have strange features, let us not forget that they are animals too like the common animals we encounter. We may sometimes neglect their importance and their presence, but let us be reminded that they play vital roles to humans and in maintaining ecological balance thus conserving and protecting them is substantial. Domain Eukarya-Animals (Chordates) Tunicates The tunicates, Subphylum Urochordata, include the sea squirts, salps, and pyrosomes. Larval tunicates resemble tadpoles. Their expanded body has pharyngeal slits, notochord, and dorsal nerve cord which they retain until adulthood. Adult tunicates grow soft and transparent or leathery protective covering called tunic. Their tunic have incurrent siphon; an opening that lets the water and food in their body, and excurrent siphon, an opening that lets their waste, gametes (reproductive organ), and the water out of their body Many are suspension feeders that remove plankton from the stream of water passing through the pharynx, while some are predatory species that feed on other invertebrates such as crustaceans. Generally, they are hermaphroditic and sexually reproduce by cross-fertilization while there are some that can reproduce asexually by budding. Ecological role and their significance to humans Larvaceans, a class of tunicate, create two net-like mucus filters as its "house" which only last for 24 hours. Once it deflated, these cast-off larvacean houses, commonly known as "sinkers" have been discovered as an additional food source that was more than sufficient to feed all deep-sea animals (Robinson, et. Al., 2005). Tunicates are vital part of the food chain and provide a source of food to humans indirectly. They prove to be important in providing clues to the possible ancestry of vertebrates. Lancelets Subphylum Cephalochordata consists of lancelets or amphioxus. Lancelets are translucent, fish-shaped animals, 5 to 10 cm long, pointed at both ends and commonly scattered in shallow seas, either swimming freely or burrowing in the sand near the low-tide line. The notochord in lancelet goes from their head to their tail. Lancelets are similar looking to fish but they lack organs such as a well-developed head or brain, a heart, sense organs, paired fins, and jaws. They use their tentacles to draw a current of water into their mouth where food particles are trapped in the mucus in their pharynx and the mucus is rolled up and transported to their intestine, where food is digested and absorbed. They can move fast on the gravel they live in by swimming forward and backward. They reproduce through sexual reproduction where their eggs and sperms are shed directly into the water until it is fertilized. Ecological role and their significance to humans Lancelets' molecular and structural characteristics may answer the process of transition of invertebrates to vertebrates and greatly contributes to the study of evolution by providing information to the history of human lineage. Researchers studied how the lancelet controls its gene activity (Marlétaz, F., et al., 2018), to know which control mechanisms evolved with vertebrates, and which were already present Fishes Some of the earliest known vertebrates are the jawless fishes. Their whole body is armored, though they lack fins. They strained their food from the water, just like the tunicates and lancelets and they lived on the bottom of the sea. Hagfishes and lampreys are one of the common examples of the modern-day jawless fish. Both of them do not have jaws or fins and lack the ancestral armored body for they are smooth skinned, eel-like animals whose bodies are supported by a cartilaginous skeleton and well-developed notochord. Hagfishes are scavengers, while lampreys are parasites. Can you imagine? It must have been hard to hunt for food when they are jawless! The cartilaginous fishes are ocean dwellers, but a few have invaded fresh water. They have cartilaginous skeleton, paired jaws, two pairs of fins, skin that contains placoid scales (cartilaginous, spiny, toothlike projections), and continuous tooth replacement. They are suspension feeders and reproduce sexually; some are ovoviviparous; their young are enclosed by eggs that are incubated in the mother's body , others are viviparous; the young grows in their mother's womb and nourished by nutrients transferred by their mother's blood. Examples of cartilaginous are whales, sharks, skates, and rays. Bony fishes, like the cartilaginous continuous tooth replacement. Majority of the bony fishes are defined by a bony skeleton with many vertebrae. Bone provides more excellent support than cartilage and effectively stores calcium. They have scales that cover their body, and an operculum; a lateral bony flap that extends posteriorly from the head and protects the gills. They are oviparous; lay an impressive number of eggs and fertilize them externally. Fishes are ectotherms; organisms that cannot maintain a constant body temperature. Ecological role and their significance to humans Aside from being a great source of food and nutrients like Vitamin D , iodine, and selenium ( Ballantyne, 2012), fish gives a number of by products such as fish oil, fish manure, fish glue, isinglass, raw material in the preparation of special cement and in the clarification of wine and beer (Biology Discussion, 2012). Fishes also assist in controlling diseases like malaria. Some studies showed that introducing fishes that eat larva of mosquito, to a habitat have reduced the population of larvae and pupae of mosquitos (Louca et. al, 2009). Amphibians Amphibians, like lizards, newts, and salamanders, may have visible tail; or like toads and frogs, may not have tail but with legs; or like wormlike caecilians may have no feet at all. Amphibians spend their early life on water and move to land as they turn into adults, however, they return to the water to reproduce. Their eggs and sperm are released in the water. Once their eggs are fertilized, they store it in a moist environment so it will not dry out. Amphibians undergo metamorphosis, a transition from larva to adult as observed in most frogs and toads. The tadpoles feed on aquatic animals. They have tails and gills. Their thyroid gland secretes hormones to stimulate metamorphosis. During metamorphosis, their gills and gill slits disappear, their tail is resorbed, and limbs emerge. Furthermore, their mouth expands where a tongue grows, they develop an eardrum and eyelids, and their eye lenses change shape. Their digestive tract shortens and their diet changes from plant based to a carnivorous one. However, several salamanders, such as the mudpuppy, Necturus, do not undergo complete metamorphosis and retain their larval characteristics even when they are sexually mature adults. The amphibians' skin plays varying roles in their survival. The color of their skin may be brightly striking that warn predators that they are not encountering an ordinary amphibian but a poisonous one or a color that conceals them within the environment that make them hard to be spotted by predators Their skin which lacks scales serves as a respiratory surface. The mucous glands within their skin help keep their body surface moist which is important in gas exchange, makes them slippery, thus, they are harder to catch, and secretes poisonous substances harmful to predators. Amphibians, like fishes, are ectotherms. Ecological role and their significance to humans Amphibians prey on insects that transmit diseases or destroy crops which is helpful in reducing its population. Some of the tropical frogs' skins secretes magainin, a substance found to be a natural antibiotic. (Ge et. al., 1999), and Epibatidine, a toxin from a South African frog's that has potential use as anesthetics and painkillers (Salehi et. al., 2018). Reptiles Tuatara, a reptile formally classified as a lizard was proven and acknowledged as the sole surviving member of an ancient reptile group older than dinosaurs, and the only cousin of lizards. They play a significant part in understanding the evolution of all animals with backbones. The evolution of efficient lungs and circulatory systems for exchange of oxygen and carbon dioxide came in second. It has solved the problem of land vertebrates with a skin that minimizes water loss and largely decreases gas exchange. Reptiles have hard, dry, and horny scales as its skin that prevents effective flow of gases between the body and environment, because of this, reptiles have better developed lungs and three-chambered heart. Reptiles are ectotherms. Most of them bask in the sun to raise their temperature or hibernate to conserve their temperature. Many of them are meat-eating animals and very good predators. Common examples of reptiles are lizards, snakes, and amphisbaenians (worm lizards), tuataras, crocodiles, alligators, caimans, gavials, turtles (aquatic form), tortoises (land species), and terrapins (freshwater types). Ecological role and their significance to humans Reptiles have a noteworthy economic value for food and ecological services, such as insect control. An article from Animal Bytes from Busch Garden states that overpopulation of fish species in wetlands and coastal regions is prevented by reptiles like alligators and crocodiles which is crucial in keeping healthy and stable aquatic ecosystems. They are valued globally for food and medicinal products. Vaccines are often derived from the venom of snakes. Reptile scales are considered fashionable in many cultures and are expensive leather goods. Three percent (3%) of households in the USA have at least one pet reptile (Stutsman, 2020). Bird Evolutionary biologists proposed that birds evolved from the lineage of dinosaurs. Like the dinosaurs, modern-day birds lay eggs and they have scales. However, unlike the dinosaurs, they are endotherms; they can regulate their own body temperature independent of its environment. They are the only vertebrates adapted to flying. The ability to fly is ascribed to their light feather, compact bodies, hollow and porous bones, and large flight muscles. In addition, they do not have a urinary bladder; they excrete nitrogenous wastes in the form of semisolid uric acid. If you had ever wondered why birds drop their feces to the ground or sometimes, on your head, it is so that they can retain their light weight while flying. However, there are birds that cannot fly like the penguins and the ostriches. One of the most intriguing behaviors of birds is their annual migration affected by the earth's seasons and magnetic field. Common examples of birds are eagles, bluebirds, humming, birds, flamingos, and many more. Ecological role and their significance to humans Birds pollinate plants, control pests, and many more. Birds play an essential role in marine systems', such as coral reefs, nutrients cycles. Islands free of invasive seabird predators have more healthy and abundant coral reefs, with fish growing larger and faster for their age, compared to islands with seabird predators (Benkwitt, 2019). Mammals Mammals are classified as animals with hair that covers, insulates, and protects the body, and mammary glands, which produce milk for the young. Mammals are the only chordates that have teeth divided into incisors, canines, premolars, and molars. Their nervous system is more highly developed than any other group of animals. Their limbs developed to be suitable for running, climbing, walking, burrowing, swimming, or flying. They are endotherms. Modern mammals are categorized into three groups: the egg-laying mammals like duck-billed platypus, the marsupials, or pouched mammals like kangaroos; and the placental mammals like humans. All of them possess amniotic sac, a derivative of amniotic egg. Most modern-day mammals are viviparous (young develop inside the mother's body). Egg-laying mammals lay eggs that they carry in a pouch on their abdomen. Once hatched, they feed their offspring with milk by lapping up milk from their mammary gland because they do not have nipples. Marsupials\' offspring are born undeveloped. They crawl to the marsupium (pouch) where they complete their development. They feed milk through their mother's nipples. Placental mammals develop a placenta, an organ that allows the mother to supply nourishment and oxygen to the developing embryo and carries off wastes. Placental mammals are born at a more mature stage than marsupials. Ecological role and their significance to humans Mammals are important drivers of ecosystem function, structure, or dynamics (Roemer et. al,2009). Aside from food and clothing, humans have used domesticated strains of the mammals such as house mouse, guinea pig, and other species as laboratory subjects for the study of human-related physiology, psychology, and a variety of diseases from dental caries to cancer. The study of nonhuman primates (monkeys and apes) has also opened broad new areas of research relevant to human welfare (Amstrong et. Al, 2020). FORMATIVE ASSESSMENT List two (2) animals and describe each as to their: 1) body symmetry 2) presence/absence of cephalization 3) presence/absence of body cavity 4) sex determination 5) skeleton type 6) habit FORMATIVE ASSESSMENT Direction: Choose the correct answers among the choices given in each item. Encircle the letter of your choice. 1. A type of skeleton that is formed by a fluid-filled compartment within the body, the coelom. A. Hydrostatic skeleton B. endoskeleton C. exoskeleton 2. An organism that has a false body cavity. A. Acoelomate B. Coelomate C. Pseudoacoelomate 3. A type of body from that is typically free swimming and presents a bell- shape with the mouth facing the water downwards. A. polyp B. medusa 4. The skeleton of Phylum Porifera is made up of silicon, calcium carbonate or protein called \_\_\_\_\_\_\_. A. osculum B. spongecoel C. spicule GRADED FORMATIVE ASSESSMENT Matching Type. Match the descriptions in column A with the correct terms listed inside the box. Write the term on the space in column B. They are the most ancient members of the kingdom Animalia with tiny opening, or pores all over their bodies. The concentration of nerve tissue and organs in one end of the body. They serve as the builders of habitats for a wide variety of marine life A body cavity that develops within the mesoderm and is completely lined with tissue derived from mesoderm. Other term for stinging cells that can be used for protection and to capture prey Sponges (Porifera) serve many important ecological functions, but they are best known for being an efficient\_\_\_\_\_\_\_\_. A term of having male reproductive organ in one individual and female in another It is a body form of cnidarians that is usually fixed or immobile. FORMATIVE ASSESSMENT Matching Type Direction: Match the descriptions in column A with the correct terms listed inside the box. Write the term on the space in Column B. Body segmentation is used as a distinct and distinguishing trait of the members of this phylum. Have spiny skin and an internal skeleton, with most adult exhibit five-part radial symmetry They are commonly found in the soil and aquatic habitats. Their distinguishing trait is the tough cuticle covering their bodies. This phylum has soft, unsegmented, flattened worms. Their body is covered by a mantle to enclose and protect the internal organs. Have a segmented exoskeleton and jointed appendages In this type of circulatory system, the blood is not contained in the blood vessels thus are free to move through the cavities. A stiff structure resembling a hair or a bristle, can be found in invertebrates. Arthropods and annelids have this similar characteristic B. Complete the Table. Identify one member from each phylum and provide one economic or ecological importance of the species. Phylum Member Economic and/or ecological importance Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelida Arthropoda Echinodermata FORMATIVE ASSESSMENT Matching Type. Match the descriptions in column A with the corresponding terms listed inside the box. Write the chosen term described in each number on column B. These animals develop protective covering, or tunic that is soft and transparent or quite leathery. 2. These animals are known for their hair that covers the body. 3. These animals possess a lateral bony flap that extends posteriorly from the head and protects the gills. 4. These animals spend their early life on water and move to land as they turn into adults. 5. These animals evolved from the lineage of dinosaurs. 6. They developed lungs and three-chambered heart. 7. Tunicates have this opening where water, waste products, and gametes pass to the outside. 8. Lancelets use this organ to draw a current of water and filter food from it. 9. This is the common characteristic between hagfish and lampreys 10 The cartilaginous fishes possess this unique characteristic. 11 Both bony and cartilaginous fishes possess this characteristic. 12 Amphibians undergo this process to develop a body more suited to terrestrial life. 13 This characteristic of birds made it possible for them to fly. 14 Birds do not possess this organ. 15 This is one of the most intriguing behaviors of birds. 16 This organ is present in mammals allows the mother to supply nourishment and oxygen to the developing embryo and carries off wastes. 17 Reptiles, birds, and mammals possess these two characteristics 18 19 This is a characteristic shared by mammals and some cartilaginous fishes. GRADED FORMATIVE ASSESSMENT A. Concept Map. The concept map below classifies the members of the Phylum Chordata. Write each term in its correct classification B. Dichotomous Key. Create a dichotomous key that would identify each of the members of the Phylum Chordata. Fill the box on the left with the characteristics used to group the animals on the right box. The first part is already given below. Characteristics 1. With vertebrae : without vertebrae 2. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 3. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 4. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 5. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 6. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_