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 The Diversity of Organisms "We find ourselves ethically destitute just when, for the first time, we are faced with ultimacy, the irreversible closing down of the earth's functioning in its major life systems. Our ethical traditions know how to deal with suicide, homicide and even genocide, but these traditions collapse entirely when confronted with biocide, the killing of the life systems of the earth, and geocide, the devastation of the earth itself." -Father Thomas Berry

In this day and age, I believe, our society can deal with tragedies, such as suicide, homicide, and genocide, and we can recover from these incidents. But, when faced with things like biocide or geocide, we can't even begin to wrap our minds around the problem, let alone a solution.

Within this Wiki, I'm going to explore the different levels of organisms that inhabit our planet. Also, I'll look at the relationships between the organisms, how their structures dictate the functions of the organisms, their evolutionary history, and how they interact with their environment.

__ Prokaryotes __  Domain Bacteria Kingdom Eubacteria The surface of the cell of eubacteria has what is known as a crystalline surface, or S-layer. This layer is made up of identical protein or glycoprotein subunits and makes two-dimensional arrays which show either oblique, square, or hexagonal symmetry. Bacteria can be split into two groups based on their cell wall. These two groups are gram-positive and gram-negative. In gram-positive bacteria, the subunits are connected to a peptidoglycan-containing layer. Gram-negative bacteria's subunits are connected to lipopolysaccharides. ([|Microbial physiology]) The cell surface, which is more complex than gram-negative, also contains some peptidoglycan. The lipopolysaccharides are usually toxic and the bacteria uses it as a defense mechanism. Gram-negative species are usually more threatening and more resistant than those that are gram-positive, because the outer membrane stops the entry of drugs. Many prokaryotes are covered by a capsule. This is a sticky layer of polysaccharide or protein which allows the prokaryote to attach to other surfaces or colonies. They also sheild disease-causing prokaryotes from attacks by its host's immune system. In order to stick to a substrate, some prokaryotes have hairlike appendages which are called fimbriae and pili. (//Biology,// Campbell and Reece, 2005)

The most common structure that allows for movement in prokaryotes is flagella, which consists of three basic parts: a filament, hook, and basal body. The filament is a hollow tube made up of helical chains of the protien flagellin. The hook is flexible and connects the filament and basal body. The hook rotates as protons either are pumped or diffuse from the cell. The basal body is like the motor of the flagellum. It's made up of a rod and series of rings which help anchor the flagellum to the cell wall. Flagella for prokaryotes and eukaryotes is very different. Prokaryotic flagella are one-tenth the width of eukaryotic flagella. They also are not covered by a plasma membrane. Plus, they have no internal fibrils and don't flex. Flagella have many arrangements including distribution over the entire surface of the cell or on one or both ends of the cell. The flagellum may rotate clockwise or counterclockwise. When rotating clockwise, the flagellum appears to be tumbling and this changes the direction of the bacteria. Counterclockwise rotation causes long, straight or curved actions and doesn't change the direction. Prokaryotes move differently in different environments. In a uniform environment, they move very randomly, whereas, in a heterozygous enviroment, they move in what is known as taxis, movement in response to an environmental stimulus. Responses can come from chemicals, light, osmotic pressure, oxygen, and temperature. ([|Prokaryotic flagellum])

The genomes of prokaryotes are much smaller than eukaryotes, containing one-thousandth the amount of DNA. Because of this, less DNA has to be replicated in each division in prokaryotes. DNA in prokaryotes is arranged in a large ring, known as the prokaryotic chromosome, and is found in the nucleoid. Sometimes, prokaryotes also have smaller rings of DNA called plasmids, which consist of only a few genes. Plasmids are not vital for survival. But, they can help with antibiotic resistance, metabolism of unusual nutrients, and other functions. Plasmids replicate independently of the main chromosome and can be transferred between other prokaryotes.([|Genetic organization]) Ribosomes in prokaryotes are also different from eukaryotes, being much smaller and containing different proteins and RNA. Because of differences like these, antibiotics can bind to both types of ribosomes, but only block protein synthesis in prokaryotes. (//Biology//, Campbell and Reece, 2005)

Prokaryotes replicate by a type of asexual reproduction called binary fission, or cell division. Reproduction occurs rapidly ranging from 20 minutes to 3 hours! (Biology, Campbell and Reece, 2005) Since asexual reproduction doesn't provide for much genetic variability, prokaryotes participate in transformation, conjugation, and transduction. Transformation is when prokaryotes aquire new genetic information from their surroundings. Conjugation is when two prokaryotic cells join together via a pilus. Transduction is when prokaryotes exchange DNA using phages, viruses that infect bacteria. The phage inserts its DNA into the host cell and either produces more phages within the host or insert the DNA into the host's. ([|Genetic variation in prokaryotes])

The nutritional diversity in prokaryotes is much greater than among all eukaryotes. Every way that eukaryotes obtain their nutrients can also be observed in prokaryotes. Plus, prokaryotes obtain nutrients through other nutritional modes as well. Phototrophs are organisms which obtain energy from light. Chemotrophs obtain their energy from chemicals. If an organism only needs the inorganic compound carbon dioxide for their carbon source, they are classified as autotrophs. Requiring at least one organic nutrient, like glucose, to make other organic compounds are the heterotrophs. By combining these energy and carbon source possibilities, the four major modes of nutrition are made. First, are the photoautotrophs. These organisms are photosynthetic and capture light energy to drive the making of organic compounds from carbon dioxide. Examples of photoautotrophs are:cyanobacteria, plants, and algae and certain other protists. Chemoautotrophs are similar to photoautotrophs as they also only need carbon dioxide for a carbon source, but instead of using light for energy, they oxidize inorganic substances, like hydrogen sulfide, ammonia, and ferrous ions. Only certain prokaryotes are considered chemoautotrophs, such as //Sulfolobus//. Photoheterotrophs are the next mode. They use light for energy but have to obtain their carbon in organic form. Many marine prokaryotes, such as //Rhodobacter// and //Chloroflexus//, are classified as photoheterotrophs. The last mode of nutrition is the chemoheterotroph. A chemoheterotroph has to consume organic molecules for energy and carbon. Many prokaryotes, like //Clostridium//, and protists, fungi, animals, and some plants are chemoheterotrophs. (//Biology//, Campbell and Reece, 2005)

Different prokaryotes have different relationships with oxygen. Obligate aerobes require oxygen for cellular respiration to occur. Faculative anaerobes use oxygen when it's present, but are still able to grow without it by means of fermentation. Obligate anaerobes are poisoned by oxygen. Some live by fermentation while others use inorganic molecules for electron acceptors during anaerobic respiration. ([|Prokaryote's metabolic relationships with oxygen])

Nitrogen is vital for the production of amino and nucleic acids in every type of organism. Prokaryotes have the ability to metabolize nitrogen. Some can convert atmospheric nitrogen to ammonia through a process called nitrogen fixation. The fixed nitrogen is incorporated into amino acids and other organic molecules. (//Biology//, Campbell and Reece, 2005) Eubacteria are also known as "true bacteria". There four different types of eubacteria. Gram-positive have a thick cell wall with a large supply of peptidoglycan. It's found in the air and soil; used to make Sauerkraut, buttermilk, and yogurt; used to produce antibiotics; and many cause disease. Gram-negative is the next type of eubacteria. It has lower levels of peptidoglycan; found in the respiratory, gastrointestinal, and urinary tracts; and can be antibiotic resistant. Some examples are E.coli and Salmonella. Mycoplasmas are the third type. Mycoplasmas are the smallest organisms capable of growing independently, have no cell wall, are resistant to penicillin, and cause pneumonia. The last type is cyanobacteria. These are very similar to algae, photosynthetic, live in extreme temperatures, and cause "algal" bloom. ([|types of eubacteria])

Some prokaryotes live in close association to other organisms, causing little to no harm. Sometimes, they're actually beneficial! For example, cattle, and other ruminants, can utilize the cellulose in their diets because bacteria, which contain the enzyme to break down cellulose, live in their stomachs. We humans also have bacteria living in our intestines. Some of them supply vitamin K, which helps to clot blood, and others help protect us from serious diseases. When the normal level of bacteria drops, our tissues become weakened and much more vulnerable to infection. ([|Prokaryotic symbiotic relationships])

Domain Archaea Kingdom Archaeabacteria There are three main types of archaea: Methanogens, Halophiles, and Thermoacidophiles. Methanogens are named for the way they make their energy. They use hydrogen to reduce carbon dioxide to food, giving off methane as a byproduct. Methanogens are found in anaerobic environments such as in swamp and marsh mud, in cattle and termite guts, in our colon, and in sewage sludge. Halophiles live in extremely saline environments, such as the Great Salt Lake and the Dead Sea. In order to survive in such salty environments, halophiles maintain osmotic balance by building up their solute concentration within their cells. Thermoacidophiles thrive in hot, acidic environments. Thermoacidophiles can be found in acidic sulfur springs, like those in Yellowstone, and in undersea vents. ([|types of archaea bacteria])

Archaeabacteria share several traits with eukaryotic cells. Both types of cells contain several kinds of RNA polymerase. During the making of proteins, both types use Methionine as an initiator amino acid. Introns, the noncoding part of the gene, is present in some genes of archae and all genes of eukarya. The antibiotics streptomycin and chloramphenicol don't inhibit the growth of either type. Their DNA both include histones which are positively charged proteins. (//Biology//, Campbell and Reece, 2005) __Eukaryotes__ Domain Eukarya Kingdom Protista  The Protist Kingdom shows more structural and functional diversity than any other group of organisms, it's often called the "catch-all" kingdom. All protists are eukaryotes and they all live in moist environments. The similarities end there. Protists can be divided into three main catagories: plant-like (algae), animal-like (protozoans), and fungus-like. Animal-like protists are heterotrophic, are able to move from different places in order to aquire food, and are unicellular. Animal-like protists are classified by how they move. Some move and feed by using pseudopods, bulges of cell membrane filled with cytoplasm, such as amebas. Some use hair-like projections called cilia. Cilia are like tiny oars which sweep the food into the organism, such as the Paramecium. Some protozoans, such as //Dinobryon//, use flagella to move. Those that use flagella live inside of another organism. Fungus-like protists are also heterotrophs, but they have cell walls and use spores, tiny cells which grow into a new organism, to reproduce. Fungus-like protists are unable to move at some point in their life cycle. There are three types of Fungus-like protists: water molds, downy mildews, and slime molds. Water molds and downy mildews live in mosit places and grow as tiny threads which looks like fuzz. They attack fish and food crops; they were the cause of the Irish Potato Famine in the 1800s. Slime molds also live in moist places. They are often bright colors, move by using pseudopods, and they feed on bacteria and other microorganisms. Plant-like protists are extremely varied. They're all autotrophs and are able to live anywhere. They range in size and color. An example of a plant-like protist is an Euglenoid which is green and unicellular. It can be an autotroph or heterotroph, depending on the sunlight. ([|Types of protists])

The great diversity of protists is believed to be caused by endosymbiosis. Endosymbiosis is a process in which certain unicellular organisms are engulfed by other cells. The engulfed cells became endosymbionts and later became organelles in the host cell. Biologists hypothesize that later in eukaryotic history, one lineage of heterotrophic eukaryotes acquired a new endosymbiont, a photosynthetic cyanobacterium, which then evolved into plastids. The plastids led to red algae and green algae. Biologists then believe the red and green algae underwent secondary endosymbiosis. This means they were ingested in the food vacuole of a heterotrophic eukaryote and became endosymbionts themselves. Secondary endosymbiosis gave way to: dinoflagellates, apicomplexans, stramenopiles, euglenids, and chlorarachniophytes. (//Biology//, Campbell and Reece, 2005) Scientists believe plant-like protists evolved first, then fungus-like protists, and finally animal-like protists. ([|Protist evolution]) //Giardia intestinalis// is a diplomonad which inhabits the intestine of mammals. The way people usually pick up this parasite is by drinking water contaminated with feces containing the parasite in a dormant cyst stage. //Trichomonas vaginalis,// a parabasalid, is a common inhabitant of the vagina of human females. It travels through the vagina and if the normal acidity is disturbed, it can infect the vaginal lining. The genus //Trypanosoma// of kinetoplastids causes sleeping sickness in humans, Chagas' disease, and can evade immune detection. A type of apicomplexan, //Plasmodium//, is a parasite that causes malaria and lives in both mosquitoes and humans. (//Biology//, Campbell and Reece, 2005)

Kingdom Plantae There are five key traits which appear in nearly all land plants excluding the charophyceans: apical meristems, alternation of generations, walled spores produced in sporangia, multicellular gametangia, and multicellular dependent embryos. Apical meristems are localized regions of cell division at the tips of roots and shoots. Cells that are produced by apical meristems differentiate into various tissues and generate leaves in most plants. Apical meristems allow for a plant to grow deep into the ground and tall in the air so it can get its nutrients above and below ground. The life cycles of all land plants alternate between two different multicellular bodies, this type of reproductive cycle is called alternation of generations. The two multicellular bodies that alternate in the alternation of generations are the gametophyte and sporophyte generations. Gametophyte cells are haploid (contain a single set of chromosomes) and are named for their production of haploid gametes by mitosis which fuses during fertilization. Mitotic division of the zygote results in the multicellular sporophyte. The sporophyte is the spore-producing generation. Its cells are diploid and meiosis in a mature sporophyte produces haploid spores, which are reproductive cells that can develop into a new organism without fusing with another cell. The sporophyte has multicellular organs called sporangia that produces plant spores. Within one sporangium, sporoctes, which are diploid cells, undergo meiosis and generate the haploid spores. The outer tissues of the sporangium protect the developing spores until they're released into the air. The production of gametes within multicellular organs, called gametangia also distinguishes early land plants from algal ancestors. Female gametangia are called archegonia. Each archegonium is a vase-shaped organ that produces a single egg retained within the base of the organ. The male gametangia are called antheridia. Each antheridium produces and releases sperm into the environment. Multicellular plant embryos are dependent on the female parent for nutrients. The embryo has specialized placental transfer cells which enhances the transfer of nutrients from the parent to the embryo. The multicellular, dependent embryo of land plants is so significant that land plants are known as embryophytes. (//Biology//, Campbell and Reece, 2005)

The evolution of land plants is believed to start with Liverworts, Hornworts, and Mosses about 475 million years ago. These three plants can be grouped under Bryophytes as they're nonvascular. The exact phylogeny of bryophytes is uncertain. About 420 million years ago, seedless vascular plants, such as Lycophytes and Pterophytes, developed. The origin of seed plants, which are also under the vascular group, was about 360 million years ago and included Gymnosperms and Angiosperms. (//Biology//, Campbell and Reece, 2005)

The first group of land plants consist of mosses and their allies which make up the bryophyte group. Mosses do not have seeds or flowers, so they reproduce with spores. The seta is the small bulb on a thin stalk which sticks up from the moss. The seta is the sporophyte generation. The stalk is called a foot and the bulb at the end is the capsule, which is where the sporangium is located. Since mosses have no vessels, they are a smaller size and have to be in a moist environment. Ferns and their allies make up the second group of land plants, pteridophytes. Pteridophytes all have vascular systems, made up of the xylem and the phloem. Like the first group, ferns don't have flowers and reproduce by means of spores. The spores can be found on the back of mature leaves. Each dot, called a sori contains the sporangia. The sporangia produces gametophytes. The gametophyte produces gametes which makes the fern plant. Since a fern has spores, it's the sporophyte generation. Gymnosperms make up the third generation. Instead of spores, they produce seeds within a cone. Seeds are a great evolutionary development since they're multicellular and contain nutrition for the new, developing plant. The largest group of gymnosperms are the conifers. Conifers produce pollen cones which, through meiosis, produce pollen grains. Pollen grains are immature male gametophytes. The last group of land plants are the angiosperms, also known as the flowering plants. The flower attracts animals which then assist in pollination. The seeds develop in an ovary which becomes a fruit. ([|Land plants])

Angiosperms are the most diverse and widespread of all plants-there are more than 250,000 species! All angiosperms are classified under a single phylum, Anthophyta. Current research, based on DNA studies, shows that the monocots, species with one cotyledon form one clade but the remaining angiosperms aren't monophyletic. Once called dicots, those with two cotyledons form the eudicot clade. Those that don't fit under these two classifications are divided into several small lineages. Three of the lineages are called basal angiosperms since they appear to include the flowering plants belonging to the oldest lineages. Another lineage called the magnoliids evolved later. More than one-fourth of angiosperms are monocots. Some of the larger families include the Orchid, Lily, Pygmy date palm, and Barley. Some monocot characteristics include veins, which are usually parallel; scattered vascular tissue; a root system that's usually fibrous but has no main root; pollen grain with one opening; and floral organs which usually occur in multiples of three. More than two-thirds of angiosperms fit under the eudicot classification. Some eudicots are: the California poppy, Pyrenean oak, Dog rose, Pea, and Zucchini. Eudicots usually have netlike veins, vascular tissue arranged in a ring, a main root, pollen grains with three openings, and floral organs in multiples of four or five. Basal angiosperms only consist of about 100 species. The oldest lineage is believed to be //Amborella trichopoda. A. trichopoda// is a small shrub found on the South Pacific island of New Caledonia. It lacks vessels but its tubules consist of xylem cells. The lineage that's predated only by the //Amborella// lineage is the water lily. The next lineage is believed to be the star anise. There are around 8,000 magnoliid species. They include woody and herbaceous species. Magnoliids are more closely related to monocots and eudicots even though they share several primitive traits with basal angiosperms. (//Biology//, Campbell and Reece, 2005)

Plants are vital for human survival. Most of our food comes from angiosperms, wheat, rice, and potatoes to name a few. Livestock also depends on angiosperms for feed. Flowering plants also provide nonstaple foods. Two of the world's most popular beverages come from tea leaves and coffee beans. Cocoa, chocolate, and spices also are harvested from different plants. Many seed plants are sources of wood, which is the primary source of fuel for much of the world. Wood is also used to make paper and is the most widely used construction material. Humans have also depended on seed plants for medicines. Lastly, and most importantly, plants give off oxygen as a biproduct from photosynthesis. Without oxygen, we oxygen-breathing organisms wouldn't be able to live! (//Biology//, Campbell and Reece, 2005)

Kingdom Fungi Fungi are mostly multicellular eukaryotes. They're heterotrophic by absorption and most consume dead organisms or organic waste and are called saprophytic. The cell walls of fungi contain chitin for structural support. The feeding portion of fungi is a root-like network of filaments called mycelium, each individual filament is called a hyphae. In order to spread, fungi create a reproductive structure which spreads spores by wind. ([|Fungi])

Phylogenetic systematics belive that fungi evolved from a flagellated ancestor. Phylogenetic evidence also suggests that the ancestor of fungi was unicellular. Scientists estimate that the ancestors of animals and fungi diverged into separate lineages 1.5 billion years ago. Chytrids diverged earliest in fungal evolution. Next came the zygote fungi, then the arbuscular mycorrhizal fungi. Sac fungi and club fungi were the last to diverge. (//Biology//, Campbell and Reece, 2005)

Fungi are divided into 4 different groups, Zygomycota, Ascomycota, Basidiomycota, and Deuteromycota. The zygomycota have symbiotic relationships with plants. Many live in soil and feed on dead animals and plant remains. They are parasitic of some insects and plants and reproduce sexually. Black bread mold and other forms of mold are examples of zygomycota. Ascomycota include yeasts and powdery mildews. Their hyphae are subdivided by porous walls which allow the cytoplasm and nuclei to pass through. Ascomycotas divide by both asexual and sexual reproduction. Basidiomycota also have hyphae subdivided by porous walls. The feature that makes basidiomycota different is that two hyphae fuse, forming dikaryotic mycelium which differentiate into reproductive structures and later create spores. Basidiomycota includes gill and pore fungi. Deuteromycota is the group that catches the fungi which don't fit perfectly into the other divisions. One thing they all have is a lack of sexual reproductive features. ([|types of fungi]) Fungi function as decomposers. They break dead matter down into simple compounds that plants around it can absorb. When decomposing, fungi release carbon dioxide into the atmosphere as well. Some fungi grow around plant roots. The dead matter fungi decomposes leaves behind nutrients the plant requires. Some fungi also are used in recipes to add flavor. ([|roles of fungi]) Kingdom Animalia Animals are unable to make their own organic molecules, so they have to ingest them. This nutritional mode is known as heterotrophic. Unlike fungi, who're also heterotrophs, animals use enzymes to digest their food after ingesting it. Animals are eukaryotes and are multicellular. But, animals do not have cell walls. Instead, their bodies are held together by structural proteins, most being collagen. Not only do animals have structural proteins, they also contain muscle and nerve cells and three types of junctions: tight junctions, desmosomes, and gap junctions. Most animals reproduce by sexual means. Most species have sperm with flagella which fertilize eggs, larger and nonmotile. Together, the two form a diploid zygote.(//Biology//, Campbell and Reece, 2005)

Since animals are so diverse, zoologists need ways to categorize them. One way to catagorize animals is according to the symmetry of their body, or lack thereof. There are two different types of symmetry: radial and bilateral. An animal with radial symmetry's parts of the body radiate from the center. If you were to divide the animal into four parts, it should be a mirror image. An animal with radial symmetry is the sea anemone. Bilateral symmetry is when an animal is symmetrical on two sides. An animal that's bilateral has a dorsal, or top side, and a ventral, or bottom side. They also have a head on their anterior side and a posterior side with a tail. There are many animals that are bilaterally symmetrical such as arthropods and mammals. (//Biology//, Campbell and Reece, 2005)

Animals bodies also vary in the way their tissues are arranged. During gastrula, discussed later, the embryo becomes layered. These layers are called germ layers. As the embryo continues developing, the layers form the various tissues and organs of the body. The ectoderm is the germ layer which covers the surface of the embryo and later the outer covering of the animal. The Endoderm is the innermost layer and lines the developing digestive tube and later lines the digestive tract and the related organs. Some animals also have a third germ layer called the mesoderm. The mesoderm is located between the ectoderm and endoderm. The mesoderm forms muscles and the organs excluding the ectoderm and endoderm. Animals which have all three germ layers are called triploblastic, which include all animals which are bilaterally symmetrical. (//Biology//, Campbell and Reece, 2005)

After the sperm fertilizes the egg, the diploid zygote goes through a process calls cleavage. Cleavage is a succession of of mitotic cell divisions without the cell growing between the divisions. Cleavage then leads to a multicellular stage called blastula. In blastula, many animals take the form of a hollow ball. After blastula, gastrulation takes place. In gastrulation, layers of embryonic tissues develop into adult body parts. A gastrula developmental stage results. Many animals' life cycles also include at least one larval stage. A larva is a sexually immature form of an animal that's morphologically different from the adult stage. A larva usually eats different foods and may even have a different habitat. An example of a larva is the tadpole which grows into a frog. (//Biology//, Campbell and Reece, 2005)

Cephalization is the evolutionary development of the brain. Cephalized animals' brains are large and in the anterior end of the body. The anterior end has become larger over time to accomodate the development of sensory organs. ([|cephalization])

Some triploblasts have a body cavity, which is also known as the coelom. This space is fluid-filled and separates the digestive tract from the outer body wall. A body cavity's fluid cushions the suspended organs. This helps prevent internal injuries from occuring. This place also allows for the internal organs to grow and move independently from the outer body wall. Animals known as coelomates are so-called "true" coelom. The inner and outer layers of tissue surrounding the cavity connect dorsally and ventrally forming structures called mesenteries. Mesenteries suspend the internal organs of the body. Other triploblastic animals' body cavity is derived from the blastocoel instead of from the mesoderm. These animals are called pseudocoelomates. One last class of triploblasts have no coelom and are known as acoelomates.

Subkingdom Parazoa Phylum Porifera Sponges compose the Phylum Porifera. The Porifera Phylum has no definite symmetry and a multicellular body with no organs and few tissues. These tissues surround a water filled space, although they have no true body cavity. These animals can reproduce both sexually and asexually and are sessile creatures, which means that as adults, they live attached to something. Sponges have no real nervous system and has a distinct larval stage. They live in aquatic environments and are filter feeders. ([|characteristics of Porifera]) Minchinella lamellosa is a sponge in the Porifera Phylum. It belongs to the Michinella species. Also in the Porifera Phylum are sea sponges. It's believed that these represent the earliest true multicellular animal life on earth. ([|examples of Porifera]  ) Subkingdom Eumetazoa Radial symmetry Phylum Cnideria The Cnideria phylum has two body forms: single or colonial polyps and bell-shaped medusa. Some cniderians have both polyps and medusa. Some cnideria have polyp and medusa stages in their life cycles. Cnideria are divided into three classes: Class Hydrozoa, Class Scyphozoa, and Class Anthozoa. ([|Cnideria]) The Hydrozoa class has freshwater Hydra, Obelia, and colonial Physalia. The Scyphozoa class contains jellyfish and the Anthozoa class possesses sea anemones and corals. ([|Types of cniderians]) Bilateral symmetry Acoelomates Phylum Platyhelminthes Like the Cnideria phylum, the Platyhelminthes are also divided into three classes: Class Turbellaria, Class Trematoda, and Class Cestoda. Those in this phylum have a flattened body, its digestive tract is branched and it doesn't have an anus. ([|Platyhelminthes]) Animals in this phylum include: free-living flatworms from the Turbellaria class, flukes from the Trematoda class, and tapeworms from the Cestoda class. ([|Types of platyhelminthes])

Psuedocoelomates Phylum Nematoda The Nematoda phylum is very large and consists of worms, round or thread. They freely live in the water or soil and many are parasitic towards plants and animals. ([|Nematoda]) Necator and Ancylostoma hookworms, Enterobius pinworms, the human ascaris-Ascaris lumbricoides, and the Trichinella the trichinosis worm are all included in Phylum Nematoda. ([|Types of Nematoda])

Phylum Rotifera Those in the Rotifera phylum are microscopic aquatic animals. Their habitat is freshwater or moist soil or on mosses and lichens. Since rotifers have such small and soft bodies, the only part able to be preserved through fossilization is their jaw. They are multicellular with their body cavities lined by mesoderm. They have a specialized organ system and a digestive tract with both a mouth and anus. Their diet consists mostly of dead or decomposing organic material. The Phylum Rotifera is also divided into three classes: Monogononta, Bdelloidea, and Seisonidea. ([|Rotifera]) The monogononta have only one gonad in both sexes. There's morphological differences between the males and females. ([|Monogononta]) Bdelloideans have a well-developed corona which is divided into two parts on a retractable head. They are able to move by swimming or crawling. There are no known males and the females reproduce by parthenogenesis. When put into stressful environments, they enter a state of dormancy known as anhydrobiosis. ([|Bdelloidea]) There is only one genus with two species within this order. The species are marine and only reproduce bisexually. ([|Seisonidea]) //S. nebaliae// and //S. annulatus// are the species in the Seisonidea order([|Seisonidea]). Keratella is a species under monogononta ([|Keratella]) and //Adineta vaga// is a Bdelloidean species. ([|Adineta vaga])

Coelomates/Protostome development Phylum Mollusca The Phylum Mollusca is made up of mollusks. They have soft bodies with bilateral symmetry and secrete a calcareous shell. Mollusks have an anterior head and ventral muscular foot which is used for movement. Mollusca is divided into five classes: Class Amphineura, Class Scaphopoda, Class Gastropoda, Class Pelecypoda, and Class Cephalopoda. ([|Mollusca]) Chitons are members of the Amphineura class. Tooth Shells make up the Scaphopoda class and snails and limpets make up the Gastropoda class. Class Pelecypoda contains bivalve mollusks and octopus and squid make up the Cephalopoda class. ([|Types of Mollusca])

Phylum Annelida The Phylum Annelida is composed of segmented worms and marine and freshwater species. Each segment has bristles for moving. This phylum is divided into three classes: Class Polychaeta, Class Oligochaeta, and Class Hirudinea. ([|Annelida]) Clamworms fit under the Polychaeta class, earthworms are members of the Oligochaeta class, and leeches are Hirudineans. ([|Types of Annelids])

Phylum Arthropoda The Arthropoda phylum's organisms have bodies with a head, thorax, and abdomen. Three pairs or more of jointed legs and a chitonous exoskeleton covering the body which is molted in places are also characteristics of Arthropods. Arthropods are divided into seven classes: Class Onychophora, Class Crustacea, Class Insecta, Class Chilopoda, Class Diplopoda, Class Arachnida, and Class Merostomata.([|Arthropoda]) The different classes include: walking worms for the Onychophora class; shrimp, crabs, and barnacles in the Crustacea class; insects in the Insecta class; centipedes in the Chilopoda class; millipedes belong to the Diplopoda class; spiders and ticks are in the Arachnida class; and horseshoe crabs are in the Merostomata class. ([|Types of Arthropods])

Coelomates/Deuterostome development Phylum Echinodermata Echinodermatans have a radially symmetrical body, usually in a five-part. The body wall has calcareous plates with external spines. It does have a body cavity with a water vascular system and tube feet for movement. Phylum Echinodermata is divided into five classes: Class Crinoidea, Class Asteroidea, Class Ophiuroidea, Class Echinoidea, and Class Holothuroidea. ([|Echinodermata]) Organisms within these classes are: sea lillies (Class Crinoidea), starfish (Class Asteroidea), brittle stars (Class Ophiuroidea), sea urchins and sand dollars (Class Echinoidea), and sea cucumbers (Class Holothuroidea). ([|Types of Echinodermata])

Phylum Chordata All Chordates at some point have a notochord. A notochord is a longitudinal, flexible rod located between the digestive tube and the nerve cord. The notochord is made of large, fluid-filled cells surrounded by stiff, fibrous tissue. The notochord is used to provide skeletal support to the chordate; it also acts as a firm, flexible structure for muscles to use while swimming. The chordate's nerve cord develops from an ectoderm plate to a tube dorsally located from the notochord.The hollow nerve cord is unique to chordates. Along the pharynx, a series of pouches separated by grooves form. The grooves develop into slits opening to the outside of the body, also known as gill slits. Chordates also have a tail which provides the propelling force in many aquatic species. Chordata is subdivided into three subphyla: Urochordata, Cephalochordata, and Vertebrata. (//Biology//, Campbell and Reece, 2005) Humans, salps, and aves (birds) are all members of the Chordata phylum. ([|Types of chordata])

Subphylum Urochordata The Urochordata (tunicate) belong to the deepest branching lineage of chordates. Tunicates resemble other chordates the most during their larval stage.The larva uses its tail muscles to swim to a substrate. Once it's settled on a substrate, the tunicate goes through a metamorphosis when many chordate characteristics disappear. The tail and notochord are reabsorbed, the nervous system degenerates, and the organs that remain turn 90 degrees. When it's an adult, the tunicate brings in water through an incurrent siphon and food particles are filtered from the water to a mucous net and then is transported by cilia to the esophagus. (//Biology//, Campbell and Reece, 2005) Sea squirts and pelagic tunicates are members of the Subphylum Urochordata. ([|Types of tunicates])

Subphylum Cephalochordata Subphylum Cephalochordata (lancelets) have a bladelike shape. During their larval stage, they develop a notochord, a dorsal, hollow nerve cord, many pharyngeal slits, and a tail. Alternating between upward swimming and passive sinking, lancelets feed on plankton. Adult lancelets can measure up to 5 cm long. After metamorphosis, the adult lancelets swim down to the seafloor into the sand, only leaving their anterior end out of the sand. The lancelets often leaves its burrow to make a new one. Lancelets are very rare on a global scale, but in some areas, they can reach vey high densities. (//Biology//, Campbell and Reece, 2005) //Branchiostoma floridae// and //Branchiostoma capense// are both part of the Subphylum Cephalochordata. ([|Types of Lancelets])

Subphylum Vertebrata The Subphylum Vertebrate (vertebrates) has a skull and spinal cord made of segmented vertebrate and a skeleton of cartilage or calcareous bones. This subphylum is divided into eight classes: Class Agnatha, Class Placoderms, Class Chondrichthyes, Class Osteichthyes, Class Amphibia, Class Reptilia, Class Aves, and Class Mammalia. ([|Vertebrata]) Members of the Subphylum Vertebrata include: jawless fish (Class Agnatha), armored fish (Class Placoderms), sharks and rays (Class Chondrichthyes), bony fish (Class Osteichthyes), amphibians (Class Amphibia), reptiles (Class Reptilia), birds (Class Aves), and mammals (Class Mammalia). ([|Types of Vertebrates])

Gnathostomes are animals who have developed a jaw. They are able to catch prey more easily and the jaw provides an anchor for the muscles of the mouth. Some animals who have evolved from jawless to having a jaw are whales, placoderms, and seagulls. ([|Gnathostomes])

Class Chondrichthyes Those in Class Chondrichthyes are the cartilaginous fish who have a cartilage skeleton instead of one of bone. They have five to seven gill slits on each side of their body. Some reproduce by passing the sperm from male to female. The males use specialized fins called claspers. Some produce large egg cases and others produce live young. ([|Chondrichthyes]) This class includes all sharks, skates, and rays. ([|Types of Chondrichthyes])

Class Osteichthyes Class Osteichthyes has the fish with internal skeletal bones. They have a swim bladder or lung. They also have bony scales and their gills are covered by one external gill opening. ([|Osteichthyes]) There are over 24,000 species of bony fish. This includes the ray-finned and lobe-finned fish. ([|Types of Osteichthyes])

Tetrapoda means "four legs" in Greek. Amphibians, reptiles, and mammals make up the main groups of Tetrapoda. Tetrapods include all land-living vertebrates and those that have gone back to the water to live such as sea turtles and dolpins. ([|Tetrapoda])

Class Amphibia Class Amphibia members are characterized by being tetrapods that move about on land. They have thin, soft skin and are ectothermic. They can breathe by both gills and lungs, although gills are usually used only in the larval stage. Lastly, they have a three-chambered heart with two atria and one ventricle. Fertilization can be either internally or externally. ([|Amphibia]) The Amphibian class includes salamanders, frogs, toads, and caecilians. ([|Types of Amphibians])

Class Sauropsida This class includes all reptiles. All reptiles are tetrapods and most are covered by scales. Their embryos are surrounded by an amniotic membrane and most lay eggs. There are four orders in the Sauropsida class: Squamata, Testudines, Crocodilia, and Sphenodontia. ([|Sauropsida]) Lizards and snakes belong in the Squamata order. Turtles and toroises in the Testudines order and crocodiles and alligators in the Crocodilia order. In the sphenodontia order are tuataras from New Zealand. ([|Types of Sauropsida])

Class Aves Class Aves is made up of birds, which are vertebrates with feathers. They're modified for flight and active metabolism. All birds are related through only one common ancestor. Birds have beaks and a large muscular stomach and they have a strong skeleton. They have large yolked, hard egged shells. ([|Aves]) Robins, Blue Jays, Eagles, and many other birds make up this class.

Class Mammalia The Mammalia Class is very diverse. All mammals share at least three characteristics not found in other animals such as: three middle ear bones, hair, and the production of milk by mammary glands. The inner ear bones function to transmit vibrations to the inner ear. Hair provides insulation, color patterning, and aids in the sense of touch. The female mammals produce milk to nourish their young. ([|Mammalia]) Mammals include cattle, humans, cats, dogs, horses, and about 4,995 other species. ([|Kinds of mammals])

Monotremes Monotremes are not a very diverse group. They are very similar to reptiles and birds because they lay eggs instead of having live births. They have highly modified snouts or beaks, Modern adult monotremes have no teeth. Monotremes do have one bone in their jaw, three inner ear bones, a high metabolic rate, hair, and enough milk to feed their young. ([|Monotremes]) There are only five monotreme species: the duck-billed platypus and four species of echidna (spiny anteaters). ([|Types of Monotremes])

Marsupials This group is commonly referred to as the pouched mammals. These animals give live birth, but their gestation period is short. This causes them to give birth early and the helpless embryo has to fight its way to the pouch and the mother's nipple. Marsupials are covered with hair and nurse their young. ([|Marsupials]) Marsupials include: kangaroos, wallabies, koalas, tasmanian devils, wombats, and opossums. ([|Types of marsupials])

Eutharians Eutharians (placental mammals) are very diverse. All placental mammals bear live young, nourished before birth in the mother's uterus. ([|Eutharians]) Species include rodents and bats, whales, elephants, shrews, and armadillos, farm work animals, and humans. ([|Types of Eutharians])

Biodiversity is so important on Earth! We, as organisms, need the diversity in order to be able to survive! The source of food, different for all, is fulfilled by biodiversity. Different climates has cause adaptation to take place, increasing fitness. Without the decomposers, our Earth would be one big disgusting garbage can. Without the plants, we wouldn't be able to breathe or produce energy. Without biodiversity on this planet, not only would you and I not be able to survive, but neither would the Earth.

Like I said before, our society is well trained in dealing with dying people, but when it comes to the Earth we are truly novices! We can't even fathom how big of an issue the collapse of just one system would be. This is truly evident in the way that we are causing and dealing with global warming. Earth has to stay on a perfect scale, if it tips, even just slightly, life as we now know it wouldn't be the same.