Classification of Organisms

Phylum Bryozoa

("moss animals"); one of 3 phyla of lophophorate animals, animal which possess a lophophore (a horseshoe-shaped or circular fold of the body wall bearing ciliated tentacles that surround the mouth - the tentacles trap food particles for these suspension feeders); the other 2 phyla with a lophophore are the Phoronida and Brachiopoda - these 3 phyla are almost certainly related, but their position within the protostomes or deuterostomes is debatable (molecular systematics places them closer to the protostomes, but their embryonic development resembles that of deuterostomes); bryozoans are colonial animals that superficially resemble mosses; in most species, the colony is encased in a hard exoskeleton with pores through which the lophophores can be extended; bryozoans are sessile, and most are marine (some are reef-builders)

Subphylum Urochordata

(called tunicates or sea squirts also); most are sessile; of the 4 chordate characteristics, they possess only the pharyngeal slits as adults (they have all 4 as larvae though); seawater enters the animal through an incurrent siphon, then it's filtered through pharyngeal slits, and finally it exits through their excurrent siphon; the animal is cloaked in a tunic made of a celuloselike carbohydrate; can shoot a jet of water out the excurrent siphon when molested, hence the name "sea squirt"; larvae is normally actively swimming, then metamorphoses into the sessile adult form

Division Lycophyta

(club mosses); like ferns and horsetails, _________ are seedless vascular plants; some grew to 40 m tall during the Carboniferous, but today only small ones survive; many are epiphytes (plants that use another organism as a substratum, but are not parasites); sporangia are borne on sporophylls, leaves specialized for reproduction; gametophytes are inconspicuous and may live underground for 10 yrs or more (nurtured by symbiotic fungi)

Phylum Ctenophora

(comb jellies); like cnidarians, they are members of the radiata; name means "comb-bearer", a reference to the 8 rows (combs) of fused cilia which they use to move; most have a pair of long, retractable tentacles, which bear adhesive structures called colloblasts - when prey contact a tentacle, colloblasts burst open, releasing a sticky thread that captures the food, which is then wiped off the tentacle into the mouth; most range in diameter from 1 - 10 cm, but a few ribbonlike forms reach 1 m in length

Phylum Cnidaria

(hydras, jellyfish, sea anemones, and corals); most primitive eumetazoan phylum; have radial symmetry, and are diploblastic (therefore classified as radiata); basic body plan is a sac with a central digestive compartment (gastrovascular cavity); this basic body plan has 2 variations, the sessile polyp and the floating medusa; polyps are sessile, cylindrical forms that adhere to the substrate (are sessile) - they extend their tentacles upward, waiting for prey (examples of the polyp form include hydras and sea anemones); medusae are not sessile, moving by a combination of passive drifting and weak muscular contractions - their tentacles hang downward; some cnidarians exist only as polyps, some exist only as medusae, and others alternate between the polyp and medusa forms during their life cycle; cnidarian tentacles possess cnidocytes, which contain cnidae, organelles capable of everting - cnidae called nematocysts are stinging capsules that can be thrust out of the cnidocyte and into the prey, paralyzing it; possess 2 cell layers (diploblastic), the outer epidermis and inner gastrodermis; their gastrovascular cavity acts as a hydrostatic skeleton; 3 major classes

Phylum Brachiopoda

(lamp shells); superficially resemble bivalve mollusks, but the 2 halves of the shell are dorsal and ventral to the animal, rather than lateral as in clams; live attached to their substratum by a stalk, opening its shell slightly to allow water to flow between the shells and the lophophore; all are marine; only 330 extant species are known, but there are 30,000 species of Paleozoic and Mesozoic fossils

Class Polychaeta

(marine segmented worms); name means "many setae", in reference to the fact that each segment has a pair of paddlelike or ridgelike structures called parapodia that function in locomotion; each parapodium has several setae made of chitin; the parapodia function as gills in some species; most are marine, and many live in tubes constructed by mixing mucus with sand and broken shells; the tube-dwellers include the brightly colored fanworms, which filter feed using feathery tentacles

Division Coniferophyta

(members of this division, along with the Cycadophyta, Ginkgophyta, and Gnetophyta, are collectively known as gymnosperms, "naked seeds" - seeds lack a fruit covering); gymnosperms were the first seed plants; seed plants possess the following adaptations for dry environments: 1) reduced, dependent gametophyte (protected from desiccation, somewhere on the body of the sporophyte), 2) heterospory (male microspores female megaspores, which grow into separate male and female gametophytes - reduces chance of self-fertilization), 3) seed as means of dispersal (seed consists of sporophyte embryo packaged along with a food supply, or endosperm, within a protective coat - some seeds can remain dormant for years), and 4) pollen, which is carried by animals or wind, replaces flagellated sperm; the conifers are by far the largest of the gymnosperm divisions; conifers include pines, firs, spruces, larches, yews, junipers, cedars, cypresses, and redwoods; most are large species that dominate vast forested regions of the N. Hemisphere (esp. taiga biomes); dominate in regions where the growing season is short due to high latitude or altitude; most are evergreens, and have leaves that are needle-shaped (low surface area to volume ratio an advantage to dry conditions, as well as a thick cuticle and stomata in pits to further reduce water loss); Giant sequoias are the largest organisms alive, whereas the Coast redwood is among the tallest (only certain eucalyptus trees in Australia are taller); bristlecone pines in CA are among the oldest organisms alive (one measured to be 4600 yrs old); conifers received their name because they produce cones - usually smaller pollen cones and larger ovulate cones are on the same tree; pollen is transported by wind in conifers; scales on the ovulate cone become seeds if successfully fertilized; life cycle is inefficient due to large amount of pollen wasted and lengthiness (3 years from cone production to seed formation)

Class Ostracoda

(mussel shrimps); small crustaceans that live enclosed in a bivalve carapace (hence name mussel shrimps); many have extremely long antennae, which the use to swim; many are bioluminescent

Division Gnetophyta

(one of the 4 divisions of gymnosperms); contains 3 genera that are probably not closely related (Welwitschia lives only in the deserts of southwestern Africa and its straplike leaves are the largest known leaves, Gnetum species grow in the tropics as trees or vines, and Ephedra, or mormon tea, is a shrub in the American deserts)

Division Cycadophyta

(one of the 4 divisions of gymnosperms); cycads resemble palms, but are not true palms (palms are angiosperms, flowering plants); they bear naked seeds on sporophylls, leaves specialized for reproduction

Division Ginkgophyta

(one of the 4 divisions of gymnosperms); the ginkgo (Ginkgo biloba) is the only extant (living) species in this division; it has fanlike leaves that turn gold and are deciduous in autumn, an unusual trait for a gymnosperm

Phylum Annelida

(segmented worms); includes earthworms, leeches, and polychaetes (marine segmented worms); annelida means "little rings", a reference to their segmented body plan;live in the ocean, fresh water, and damp soil; they are protostome coelomates; their coelom is partitioned by septa; the digestive system has several specialized regions, including the pharynx, esophagus, crop, gizzard, and intestine; closed circulatory system is present; their dorsal vessel, and five pairs of vessels that circle the esophagus, are muscular and pump blood through their circulatory system; skin is highly vascularized, and serves as their respiratory organ; nephridia (metanephridia) for excretion; earthworms are hermaphrodites, but they cross-fertilize; a special organ called the clitellum produces a cocoon during reproduction, which slides along the worm, picking up eggs and then the stored sperm - the cocoon slips off the worm's head and resides in the soil while the embryos develop; 3 classes exist

Class Eurypterida

(water scorpions); no living members (all extinct); eurypterids were marine and freshwater predators, and were up to 3 m long; this group outlasted the trilobites, which disappeared during the great Permian extinctions (250 mya)

Proteobacteria

3 main subgroups: 1) purple bacteria; photoautotrophs that extract electrons from H2S (no O2 released - sulfur is waste product); obligate anaerobes; found in sediments of ponds, lakes, and mudflats, 2) chemoautotrophic proteobacteria; free-living and symbiotic species (Rhizobium does nitrogen fixation in root nodules of legumes, converting N2 to NH3, which is later converted by nitrifying bacteria into nitrate, a form of nitrogen plants can use), 3) chemoheterotrophic proteobacteria; includes enteric bacteria, most of which are rod-shaped facultative anaerobes which are usually harmless (such as E. coli), but others are pathogenic (Salmonella causes food-poisoning)

Pseudopodians

a diverse group of organisms move and often feed using cellular extensions called pseudopodia; examples of pseudopodians include rhizopods (naked and shelled amoebas previously classified in the Phylum Rhizopoda or Sarcodina), actinopods (axopodians previously classified in the Phylum Actinopoda), foraminiferans (marine amoebas previously classified in the Phylum Foraminifera), myxomycotes (plasmodial slime molds, previously classified in the Phylum Myxomycota), and Acrasiomycotes (cellular slime molds, previously classified in the Phylum Acrasiomycota); relationships among these groups have not yet been identified, but they surely compose several distinct lineages; rhizopods (commonly called amoebas) are all unicellular and use pseudopodia to move and feed - pseudopodia extended by means of pushing the cytoplasm with the cytoskeleton, a phenomenon known as cytoplasmic streaming); actinopods include heliozoans and radiolarians - actinopod ("ray foot") refers to slender pseudopodia called axopodia that radiate from their bodies; heliozoans ("sun animals") live in fresh water and have skeletons consisting of siliceous (glassy) or chitinous unfused plates; radiolarians have their silica skeletons fused into one delicate piece (most are marine - shells form a deep "radiolarian ooze" that is 100s of meters thick in some places; foraminiferans (forams) are named for their porous shells consisting of organic material hardened with CaCO3; fossilized foram shells make up many sedimentary rocks that are now land formations (such as the White Cliffs of Dover); the similarity of slime molds to fungi is due to convergent evolution - both have a filamentous body structure, enhancing their ecological role as decomposers; plasmodial slime molds are terrestrial heterotrophic decomposers with a multinucleate amoeboid feeding stage called a plasmodium; cellular slime molds have a feeding stage that consists of solitary cells that function individually - but when food is depleted, the cells form an aggregate that functions as a unit - the mass resembles a plasmodial slime mold, except for the fact that the cells are haploid, and they remain separate (not multinucleate)

Order Hymenoptera

ants, bees, and wasps; 2 pairs of membranous wings; head mobile; chewing or sucking mouthparts; posterior stinging organ on females; complete metamorphosis; many species are social (eusocial insects - queen is a reproductive female, workers are non-reproductive females that care for the young and defend the queen, drones are reproductive males)

Division Ascomycota

ascomycetes or sac fungi; group includes unicellular yeasts, small leaf-spot fungi, and elaborate cup fungi and morels; many are saprobes, but about half of the species live together with algae in mutualistic associations called lichens; some (including the morels) form mycorrhizae with plants; many are devastating plant pathogens (cause Dutch elm disease, which is carried from tree to tree by bark beetles; one species has almost eliminated the American chestnut; another type forms purple structures called ergots on rye - if milled into flour and consumed, it can cause gangrene, nervous spasms, hallucinations and temporary insanity - ergots contain lysergic acid, the raw material for LSD); the defining structure of the ascomycetes is the production of sexual spores in saclike asci (sing. ascus); most sac fungi bear their sexual stages in macroscopic fruiting bodies called ascocarps; have a more extensive dikaryotic stage than zygomycetes; after plasmogamy, the cells at the tips of the dikaryotic hyphae become the asci; within the asci, karyogamy combines the 2 parental genomes, then meiosis forms the genetically varied ascospores

Class Cirripedia

barnacles; only sessile (attached in one spot) crustaceans; body is covered by heavy, calcareous plates; the plates on the upper surface open like windows, allowing their feathery filtering appendages (cirri) to sweep through the water

Division Basidiomycota

basidiomycetes, including mushrooms, shelf fungi, puffballs, rusts, and smuts; name derived from the basidium, a transient diploid stage in their life cycle; sometimes called club fungi, due to the clublike shape of the basidium; important composers of wood an plant material (they are the best at decomposing lignin), although some are mycorrhizal mutualists and plant parasites (shelf fungi parasitize wood of weak or damaged trees - rusts and smuts are also destructive plant parasites); life cycle usually includes a long-lived dikaryotic mycelium, which, in response to environmental stimuli, reproduces sexually by producing elaborate fruiting bodies called basidiocarps (the basidia of the basiocarps are the source of the sexual spores); a mushroom is an example of a basidiocarp (mushroom is composed of a stalk, cap, and gills - the basidia hang off of the edge of the gill)

Order Coleoptera

beetles; 2 pairs of wings (1 pair thick and leathery, the other membranous); armored exoskeleton; biting and chewing mouthparts; complete metamorphosis

Class Insecta

body divided into head, thorax, and abdomen; antennae present; mouthparts modified for chewing, sucking, or lapping; usually with 2 pairs of wings and 3 pairs of walking legs; mostly terrestrial; outnumber all other forms of life combined; entomology = the study of insects; greatest diversification of may have come during the angiosperm diversification, or it may have caused the adaptive radiation of angiosperms; flight is one key to the success of insects - wings are extensions of the cuticle, and are thus not true appendages (does not sacrifice any walking legs, as in birds - usually 1 or 2 pairs of wings); many wing modifications exist - bees and wasps have their wings hooked together so they move as a single pair, and butterflies have their anterior an posterior wings overlapping so they move together also; in beetles, the posterior wings function in flight while the anterior ones are modified as covers that protect the flight wings; excretion is done using Malpighian tubules; gas exchange is accomplished by a tracheal system of branched, chitin-lined tubes that infiltrate the body and carry oxygen directly to the cells (the openings of the tracheal system to the environment are called spiracles - they can open and close to regulate air flow and water loss); many insects undergo metamorphosis during development; during incomplete metamorphosis (seen in grasshoppers), the young resemble adults but are smaller and have different body proportions - the animal goes through a series of molts, each time looking more like an adult; insects with complete metamorphosis have larval stages specialized for eating growing (examples are the maggot, grub, or caterpillar) - the larval stage looks entirely different from the adult, which is specialized for dispersal and reproduction - metamorphosis from the larval stage to he adult occurs during a pupal stage; 26 orders exist

Class Ophiuroidea

brittle stars; distinct central disk present (arms do not join at the central disk, but rather are and thin and radiate independently from the central disk); tube feet lack suckers, so they move by serpentine lashing of the arms (are fastest moving echinoderms); use tube feet to pass particles to mouth (most are scavengers)

Order Lepidoptera

butterflies and moths; 2 pairs of wings covered with tiny scales; long coiled tongue for sucking; complete metamophosis

Class Chilopoda

centipedes; body with distinct head bearing large antennae and 3 pairs of mouthparts; the appendages of the first body (trunk) segment are modified as poison claws; segments bear one pair of walking legs each; terrestrial carnivores

Class Polyplacophora

chitons; marine animals with a shell divided into 8 dorsal plates; use foot to grip rocks in the intertidal zone (can create incredible suction); act as grazers on algae, using their radula to scrape and ingest the algae

Division Chytridiomycota

chytrids; mainly aquatic, but some are saprobes or parasites; form link between protists and fungi; were once placed into Kingdom Protista due to their formation of flagellated spores (zoospores); now thought to be part of the Kingdom Fungi, due to comparisons of nucleic acid sequences, as well as their absorptive mode of nutrition and cell wall made of chitin; most are coenocytic, and many believe they are the most primitive fungi (fungi probably evolved from flagellated protists, a feature retained in the fungal kingdom only by chytrids)

Domain Eukarya

commonly called eukaryotes; contains the Kingdoms Protista, Plantae, Fungi, and Animalia from the traditional 5-kingdom system of classification; cells contain a nucleus (usually) and other membrane-bound organelles; no peptidoglycan in cell wall (if present); several kinds of RNA polymerase; methionine is the initiator amino acid for protein synthesis; introns are present; growth not inhibited by antibiotics; chromosomes are linear; cell division is by mitosis or meiosis (when forming gametes), not binary fission as in prokaryotes; probably evolved by a combination of endosymbiosis (one large prokaryote engulfed a small prokaryote, which, instead of being digested, formed a symbiotic relationship within the larger cell - eventually evolved into mitochondria and chloroplasts - evidence is that these 2 organelles have their own DNA, which is in a loop not bound together by histones, and they are surrounded by 2 membranes, and these organelles are not susceptible to antibiotics and can divide on their own) and the autogenous hypothesis (prokaryotic cell invaginated its own membrane, forming structures that eventually evolved into ER, Golgi apparatus, etc.)

Candidate Kingdom Stramenopila

contains diatoms (considered single-celled algae in the Division Chrysophyta or Bacillariophyta in previous classifications), golden algae (considered single-celled or colonial algae in the Division Chrysophyta in previous classifications), brown algae ( considered multicellular algae in the Division Phaeophyta in previous classifications) and the oomycetes (water molds, white rusts, and downy mildews); term stramenopila refers to numerous fine, hairlike projections on their flagella (not all have flagella, though); photosynthetic stramenopiles have unusual chloroplasts, with 2 additional membranes outside the usual chloroplast envelope and a vetigial nucleus - probably descended from endosymbionts that were eukaryotic cells (probably red algae); diatoms have glasslike walls consisting of hydrated silica embedded in an organic matrix - each wall is in 2 parts that overlap like a shoe box and lid; diatoms, along with dinoflagellates, are the dominant forms of phytoplankton in aquatic ecosystems; diatoms usually reproduce asexually through mitosis, with each daughter cell receiving half of the shell (have to regenerate the other half - when get too small, they discard old shell and grow a complete new shell - diatom shells on the bottom of the ocean have accumulated up to 1 mi thick at the bottom, forming "diatomaceous earth" which is mined for use in toothpaste, among other things); golden algae are named for their color, and are normally biflagellated, single-celled organisms (some are colonial) - most are autotrophic but some are heterotrophic; water molds are heterotrophic stramenopiles that are unicellular, or consist of coenocytic hyphae (analogous to fungi, except cell wall made of cellulose, not chitin); most water molds are decomposers that grow as cottony masses on dead animals and algae, usually in freshwater, although some are parasitic; white rusts and downy mildews are parasites of land plants (one form caused one type of late potato blight during the Irish famine); oomycetes got their name by the fact that they produce a large egg cell that is fertilized by a smaller sperm nucleus, forming a resistant zygote; brown algae are all multicellular and most are marine (their chloroplast structure and pigment composition is homologous to that of golden algae and diatoms - contain chl a, chl c, and carotenoids, with fucoxanthin especially abundant in this group, making them brown or olive green); large, multicellular algae are often called seaweeds; brown algae are the largest seaweeds, and are the dominant primary producers along our coast; the seaweed body is called a thallus, and consists of a holdfast (which anchors the alga), a stem-like stipe, and leaflike blades which are supported by the stipe (some are equipped with pneumatocysts, little floats that keep the blades near the surface); the multicellular algae usually follow a complex life cycle called an alternation of generations, the alternation of a multicellular diploid form (sporophyte) with a multicellular haploid form (gametophyte); the sporophyte produces haploid spores by meiosis, which grow by mitosis into male and female gametophytes; the male gametophyte produces sperm by mitosis, whereas the female gametophyte produces eggs by mitosis; the egg and sperm undergo fertilization, forming a diploid zygote, which then grows by mitosis into a new sporophyte (completing the life cycle); all plants also undergo an alternation of generations within their life cycle; brown algae produce a gel-forming agent called algin, which is used as a thickening agent in shampoo and ice cream (large brown algae are called kelp, by the way - largest is Macrocystis, the giant kelp)

Candidate Kingdom Alveolata

contains dinoflagellates (considered single-celled algae in the Division Pyrrophyta in previous classifications), apicomplexans (considered protozoans in the Phylum Sporozoa in previous classifications), and ciliates (considered protozoans in the Phylum Ciliophora in previous classifications); all alveolates have small membrane-bounded cavities (alveoli) under their cell surfaces (function unknown); dinoflagellates are an important component of phytoplankton, the foundation of most marine ecosystems; dinoflagellate cell walls are usually reinforced with extra plates of cellulose; the beating of 2 flagella in perpendicular grooves in their "armor" produces a spinning movement for which they are named; dinoflagellate algal blooms (bursts of explosive population growth) cause red tides (many produce toxins that can kill humans that eat shellfish during these blooms - shellfish prey on dinoflagellates, and concentrate the toxin); some live as mutualistic symbionts (called zooxanthellae) of coral reef polyps (their photosynthetic output is the main food source of coral reef communities); apicomplexans are parasites of animals - they contain a complex of organelles at one end (the apex) that is specialized for penetrating host cells and tissues (hence their name); most have intricate life cycles involving 2 or more different host species (example is Plasmodium, the parasite that causes malaria - mosquitoes in the genus Anopheles act as intermediate hosts - infect liver and RBCs of humans, lysing them); ciliophorans move using cilia; they are the most complex single-celled organisms, containing (among other things) an oral groove lined with cilia (where food in engulfed), usually 2 contractile vacuoles (expel excess water), and 2 types of nuclei (a macronucleus which controls everyday functions, and usually several tiny micronuclei, which are exchanged during sexual reproduction and develop into the macronucleus of the next generation); classic ciliate example is Paramecium

Candidate Kingdom Euglenozoa

contains euglenoids (considered single-celled algae in the Phylum Euglenophyta in previous classifications - example is Euglena) and kinetoplastids (considered flagellated protozoans in the Phylum Mastigophora in previous classifications - example is Trypanosoma, the cause of African sleeping sickness); euglenoids can act as photoautotrophs (carrying out photosynthesis) or as heterotrophs (engulf food by phagocytosis), and they have a light-sensitive eyespot to help find light (they contain the same pigments as land plants, chlorophyll a, chlorophyll b, and carotenoids); kinetoplastids have a single large mitochondrion associated with a unique organelle, the kinetoplast, that houses extracellular DNA; some kinetoplastids are symbiotic, whereas others are pathogenic

Candidate Kingdom Rhodophyta

contains the red algae (considered multicellular algae in the Division Rhodophyta in previous classifications); unlike other eukaryotic algae, they lack flagellated stages in their life cycle (lost during evolution); reddish due to phycoerythrin, an accessory pigment found in red algae, cyanobacteria, and other organisms whose plastids were derived from red algae or cyanobacteria; their phycobilins (phycoerythrin and phycocyanin) allow them to absorb filtered blue and green light (which means some can live fairly deep in the ocean); harvested for the gel-forming agents carageenan and agar (used as thickeners and as a growth medium for bacteria); most are multicellular and the largest are called seaweeds; coralline forms have calcium carbonate embedded in their cell walls

Class Malacostraca

crabs, lobsters, and shrimp; first 1-3 thoracic appendages are modified to form feeding structures called maxillipeds; the 1st 5 pairs of abdominal appendages are called pleopods, and can be used to swim or for creating water currents to ventilate the gills

Order Decapoda

crabs, shrimp, lobsters, and crayfish; 5 pairs (10 total) of legs, hence their name; first pair of thoracic appendages are normally heavily constructed to form chelipeds ("claws"), which are used for predation and defense; hermit crabs lack a shell covering their abdomen, and instead normally tuck their abdomen inside of a gastropod (snail) shell; most crabs have their abdomen tucked underneath their thorax (except hermit crabs)

Order Orthoptera

crickets, roaches, grasshoppers, mantids; 2 pairs of wings (1 pair leathery, 1 pair membranous); biting and chewing mouthparts; incomplete metamorphosis

Class Oligochaeta

earthworms and their relatives; practice deposit feeding (eat soil, then extract nutrients from it as it passes through the digestive tube); undigested material, mixed with mucus from the digestive tract is egested as castings through the anus; this aerates the soil, and the castings improve the texture of the soil

Kingdom Fungi

eukaryotes, and most are multicellular; heterotrophs that acquire nutrients by absorption (food is digested outside of body by enzymes, then absorbed across the body wall); do extracellular digestion because their cells possess a cell wall made of chitin; most fungi are decomposers (break down dead material - called saprobes or saprophytes sometimes), but some are parasitic (Athlete's foot, ring worm) or mutualistic (mycorrhizae are a relationship between a fungus and the root of a plant, whereas a lichen is a relationship between a fungus and an algae/ cyanobacterium); except for unicellular yeast, the bodies of fungi are normally constructed of thread- like units called hyphae (sing. hypha); the hyphae form an interwoven mat or network called a mycelium, the feeding network of a fungus (hyphae and mycelia are usually subterranean); one fungal mycelium was found to spread through 6.5 km2 of land, and was probably thousands of years old, qualifying it among the Earth's oldest and largest organisms; most fungi are multicellular, divided into cells by cross-walls called septa (sing. septum); the septa have holes large enough to move ribosomes, mitochondria, and even nuclei from cell to cell; some fungi are aseptate, resulting in the coenocytic condition (one cell, thousands of nuclei - results by repeated nuclear division without cytoplasmic division); the filamentous structure of the mycelium provides extensive surface area for absorption; parasitic fungi usually have some hyphae modified into haustoria, nutrient-absorbing hyphal tips that penetrate the tissues of the host; fungi reproduce by releasing spores that are produced either sexually or asexually; in the sexual cycle of many fungi, syngamy (the sexual union of cells from 2 individuals) occurs in 2 stages that are separated in time - these stages are plasmogoamy (fusion of the cytoplasm) and karyogamy (fusion of nuclei) - after plasmogamy, the nuclei from each parent pair up but do not fuse, forming a dikaryon - the fungus may exist in this dikaryotic state for months or years; most fungi spend the majority of their lives in the haploid state

Division Pterophyta

ferns; ferns, along with lycophytes (club mosses) and horsetails, are all seedless vascular plants; these plants were the first to develop vascular tissues, consisting of xylem for carrying water and minerals, and phloem for carrying sugars (usually sucrose) and other organic nutrients; xylem is composed of tracheids (in all vascular plants) and vessel elements (only in vascular plants with seeds - more advanced); water transport occurs via the TACT hypothesis (Transpiration, Adhesion, Cohesion, Tension), with transpiration (evaporation of water from the leaves, through the stomata) acting as the driving force for water movement; phloem is composed of 2 types of cells, sieve tube members (which conduct sugar) and companion cells (which support the sieve tube members); movement of sugar is called translocation, and occurs via the pressure flow hypothesis; xylem cells are dead at functional maturity, whereas phloem is living; vascular plants also evolved lignin, which is embedded in the cell walls and aids in support in larger vascular plants (turgor pressure helps support smaller plants); the sporophyte is the dominant stage in seedless vascular plants; most seedless vascular plants are homosporous (produce a spore that develops a bisexual gametophyte); all seedless plants still employ a flagellated sperm for fertilization, and a small, fragile gametophyte, meaning they must live in moist environments; ferns possess an extensive underground stem called a rhizome, which sends its leaves above ground; fern leaves, commonly called fronds, are compound, meaning each leaf is divided into several leaflets; the leaves emerge from the stem as highly coiled fiddleheads, which slowly unfurl; the sporangia of many ferns are arranged in clusters called sori

Phylum Platyhelminthes

flatworms; includes free-living flatworms, as well as parasitic flukes and tapeworms; all are acoelomate (lack a coelom, or internal body cavity); are the most primitive members of the bilateria (bilateral symmetry, triploblastic); lack a complete digestive tract, and instead have a gastrovascular cavity with only one opening (tapeworms lack a digestive tract altogether); lack organs specialized for gas exchange, and lack a circulatory system (they are thin enough to rely on diffusion across the body wall for exchange of substances); possess ciliated flame cells for excretion; flatworms can be divided into 4 classes

Order Diptera

flies and mosquitoes; one pair of wings and one pair of halteres (balancing organs); sucking, piercing or lapping mouthparts; complete metamorphosis

Division Anthophyta

flowering plants (angiosperms); this group is split into 2 classes, the Monocotyledones (monocots) and Dicotyledones (dicots); angiosperms are currently the dominant plants (250,000 species, compared to 720 gymnosperms; "antho" means flower, a reference to the fact that these plants are the only ones to evolve both a flower and a fruit; a flower is a compressed shoot with 4 whorls of modified leaves: sepals (small leaves at the base of the flower, which enclose the flower before it opens), petals (colorful and fragrant - used to attract pollinators), stamens ("male" parts - each consists of a stalk called a filament and a terminal sac called an anther, where pollen is produced), and carpels ("female" parts - some call them pistils - at the tip of the carpel is a sticky stigma that receives pollen; a long neck called the style leads to the ovary at the base of the carpel - protected within the ovary are the ovules, which develop into seeds after fertilization - the ovary develops into the fruit); a fruit is the mature ovary - it contains seeds, which arose from fertilized ovules; fruits are a dispersal mechanism for the seeds - relies on animals eating the fruit and carrying the seeds elsewhere; pollination is usually achieved using an animal vector (carrier), although wind pollination does occur in some species (ex - grasses, which have reduced or absent petals, an adaptation for wind pollination); a pollen grain is the immature male gametophyte, and it consists of only 2 cells, the tube and generative cells; upon pollination, the tube cell grows in length into a pollen tube, pushing the generative cell towards the ovules; as the generative cell nears the ovules, its nucleus divides to form 2 sperm nuclei; one of these nuclei fertilizes the egg, whereas the other fertilizes a cell containing 2 polar nuclei (part of the female gametophyte)- this double fertilization is a trademark of angiosperms; double fertilization produces a zygote, which develops into the young sporophyte embryo, and a triploid cell that divides to form endosperm, the nourishment for the young embryo - the protective covering of the ovule shrivels and hardens to form the seed coat, and what was once an ovule is now a seed (embryo + endosperm + seed coat); the sporophyte embryo within the seed has a rudimentary root (called a radicle) and either one or 2 cotyledons (seed leaves) - monocots have one, dicots have 2; the part of the stem below the cotyledons is called the hypocotyl and the portion above the cotyledons is called the epicotyl

Class Monogenea

flukes; most are external parasites of fishes; usually have suckers for attaching to their host, and a tough covering (cuticle) to protect them; reproductive organs nearly fill their interior

Class Trematoda

flukes; parasitize a wide variety of hosts - most have complex life cycles with an alternation of sexual and asexual stages; many require an intermediate host in which larvae develop before infecting the final host (usually a vertebrate); an example is the blood fluke (Schistosoma), which uses a snail as its intermediate host - this fluke undergoes sexual reproduction in a human, and the fertilized eggs pass out in the feces - the eggs develop into larvae in freshwater, and then enter into a snail - they undergo asexual reproduction within the snail, producing larvae that leave the snail and penetrate the skin and blood vessels of a human - about 200 million people are infected with this parasite

Domain Archaea

formerly called archaebacteria, a part of the Kingdom Monera under the traditional 5-kingdom system of classification; prokaryotes (lack nucleus and membrane-bound organelles); no peptidoglycan in the cell walls; several kinds of RNA polymerase; methionine is initiator amino acid for protein synthesis; introns are present in some genes (as in Eukarya); growth not inhibited by antibiotics (as in Eukarya); more closely related to the Domain Eukarya than to other prokaryotes (Domain Bacteria); most inhabit the most extreme environments on Earth; three main types exist (relationships are still too obscure to determine level of classification)

Domain Bacteria

formerly called eubacteria ("true bacteria"), a part of the Kingdom Monera in the traditional 5-kingdom system of classification; prokaryotes (lack nucleus and membrane-bound organelles); peptidoglycan in cell wall; 1 kind of RNA polymerase only; formyl-methionine is initiator amino acid for protein synthesis; introns are absent; growth inhibited by antibiotics; basic shapes include the spherical coccus (pl. cocci), rod-shaped bacillus (pl. bacilli), and helical spiral (includes spirilla and corkscrew-shaped spirochetes); gram-positive and gram-negative varieties (gram-positive have thick cell walls of peptidoglycan that retain violet dye, whereas gram-negative have thin cell walls that do not retain violet dye when washed with alcohol); most range in size from 1 - 5 m; many surrounded by a jelly-like capsule; many use pili (sing. pilus) to adhere to the substrate or to transfer DNA during conjugation; can take DNA in from the environment under stress (transformation); genes can also be transferred between individuals using a virus as a carrier (transduction); have a single, circular DNA molecule (chromosome), but may also have small, extrachromosomal loops of DNA called plasmids (confer antibiotic resistance); most compete with fungi in the role of decomposer, but many are pathogenic; divide (reproduce) via binary fission, which is preceded by DNA replication from a single origin of replication; about a dozen groups exist

Class Turbellaria

free-living (nonparasitic) flatworms; most are marine; members of the genus Dugesia inhabit freshwater and are known as planarians; they rely on their gastrovascular cavity to distribute nutrients throughout their body; planarians move using cilia on their ventral epidermis, gliding along on mucus they secrete; some ___________ use their muscles to swim through water with an undulating motion; the planarian head has a pair of eyespots that detect light; planarians are famous for their ability to regenerate (can cut head down the middle, and they will develop 2 heads)

Spirochetes

helical chemoheterotrophs; rotation of internal, flagella-like filaments produce corkscrew- like movements; includes free-living species and pathogens (such as Treponema pallidum, the cause of syphilis, and Borrelia burgdorferi, the cause of Lyme disease)

Division Anthocerophyta

hornworts (previously classified in the Division Bryophyta, along with mosses and liverworts); named because their sporophytes are elongated and look like horns growing out of their mat-like gametophyte; nonvascular plants

Division Sphenophyta

horsetails; like ferns and lycophytes, horsetails are seedless vascular plants; grew as tall as 15 m during Carboniferous, but only about 15 species of a single genus (Equisetum) remain; the sporangia are found at the tip, in cone-like structures; epidermis is embedded with silica, and the stems were used to scour pots and pans (were called scouring rushes); all 3 divisions of seedless vascular plants formed vast forests during the Carboniferous period (290 to 360 mya) - Europe and N. America were covered with swamps, and dead plants did not completely decay in the stagnant waters, causing the accumulation of huge amounts of organic rubble called peat - swamps were later covered by the sea, and sediments piled on top of the peat - heat and pressure converted the peat to coal, a "fossil fuel"

Division Deuteromycota

imperfect fungi; includes molds that have no sexual stages; reproduce asexually only, by producing spores; some are predatory, on roundworms and protists

Class Bivalvia

includes clams, oysters, mussels, and scallops; shell is divided into 2 halves (valves); clams can extend their muscular foot to dig, whereas oysters and mussels are sessile; scallops move by clapping their shells together, allowing them to swim; mantle cavity contains gills that are used for filter (suspension) feeding, as well as for gas exchange; they trap food particles in mucus that coats the gills, then use cilia to pass the particles to the mouth; use incurrent siphon to draw water in, and excurrent siphon to expel it; no distinct head, and the radula has been lost

Subphylum Chelicerata

includes eurypterids, spiders, scorpions, ticks, and mites; named for the fang- or pincer-like feeding appendages called chelicerae; lack antennae, unlike uniramians and crustaceans; most have simple eyes (single lens, whereas most arthropods have compound eyes); body composed of an anterior cephalothorax and posterior abdomen

Phylum Arthropoda

includes insects, crustaceans, spiders, centipedes, and millipedes; most successful animal phylum (nearly 1 million species have been described, and they inhabit nearly all habitats of the biosphere); arthropoda means "jointed feet", a reference to the fact that they possess jointed appendages; thy have a segmented body plan; groups of segments and appendages have become specialized for a great variety of functions; body is completely covered by an exoskeleton constructed from layers of protein and chitin (must molt, or shed old exoskeleton and secrete a new larger one, in order to grow); well-developed sensory organs (including eyes, of the compound variety); cephalization is extensive; have an open circulatory system, in which a fluid called hemolymph is propelled by a heart through short arteries and then into spaces called sinuses surrounding the tissues and organs; are all protostome coelomates, like mollusks and annelids; the body sinuses are collectively called the hemocoel; four subphyla exist

Class Scyphozoa

includes jellyfishes (jellies), sea wasps, and sea nettles; the medusa is the dominant stage in their life cycle; a few open ocean forms lack the polyp stage altogether; all are marine

Class Anthozoa

includes sea anemones and most corals; medusa stage is absent - only exist as polyps; all are marine, sessile organisms; corals often live in colonies; corals secrete a hard exoskeleton composed of CaCO3 - each polyp generation builds on the skeletal remains of earlier generations to construct "rocks" with shapes characteristic of the species - it is these skeletons that we call "coral"

Phylum Mollusca

includes snails and slugs, oysters and clams, and octopuses and squids; protostome coelomates; most are marine, but some inhabit fresh water or land; soft- bodied animals (molluscus means "soft"), but are normally protected by a hard shell of CaCO3; all have a body composed of 3 main parts: a muscular foot (used for locomotion normally), a visceral mass (containing most of the internal organs), and a mantle (a fold of tissue that drapes over the visceral mass and secretes the shell, if one is present); often possess a mantle cavity, which is produced by the mantle extending beyond the visceral mass (houses gills, anus, and excretory pores); many use a straplike rasping organ called a radula to scrape food; many marine forms possess a ciliated larval stage called a trochophore; excretion is via nephridia; 4 major classes exist

Class Gastropoda

includes snails and slugs; most are marine, but some fresh water and terrestrial forms exist; undergo torsion during development (visceral mass rotates up to 180 degrees, placing the anus and mantle cavity above the head in adults); most have a single, spiraled shell into which they can retreat; abalones and limpets have more flattened shells (abalones have pores for water intake); many have distinct heads with eyes at the tips of their tentacles; move via rippling motion of the foot; most use the radula to graze on plant material, although a few are predatory (use radula as a boring device or tearing apart tissue); terrestrial snails lack gills, and instead use the lining of their mantle cavity as a lung; slugs have lost their shell during evolution; many sea slugs (nudibranchs) are brightly colored and poisonous, using nematocysts from their prey to defend themselves

Class Cephalopoda

includes squids, octopuses, cuttlefishes, and the nautilus; use beak-like jaws to bite prey, then they inject poison to immobilize the victim; squids and cuttlefishes have a reduced internal shell, octopuses have lost the shell entirely, but the nautilus has a full external shell; cephalopods move by jet propulsion, firing a jet stream of water through the excurrent siphon; the foot has been modified into this muscular siphon and parts of the tentacles and head (name means "head foot"); closed circulatory system is present, as well as well-developed eyes and a large brain; giant squids are the largest invertebrates (biggest was a 17 m long specimen); the ancestors of this group were probably shelled mollusks that took up a predaceous lifestyle, such as the ammonites, shelled cephalopods that were the dominant invertebrate predators of the seas for hundreds of millions of years (disappeared during mass extinctions at end of the Cretaceous period)

Class Hydrozoa

includes the Portuguese man-of-war, hydras, and some corals; most alternate between the polyp and medusa stages, although hydras exist only in the polyp form; most are marine, although hydras are freshwater

Subphylum Uniramia

including centipedes, millipedes, and insects; primarily land-dwelling; one pair of antennae and uniramous (unbranched) appendages

Subphylum Crustacea

including crabs, lobsters, crayfish, and shrimp; most live in either marine or freshwater habitats; possess 2 pairs of antennae; like uniramians, they have jawlike mandibles to bite off bits of food; usually have compound eyes (multifaceted with many separate focusing elements); appendages are biramous (branched - uniramians have unbranched appendages); walking legs are present on the thorax, and unlike chelicerates and uniramians, crustaceans have appendages on the abdomen; most possess gills for gas exchange; can have up to 19 pairs of appendages (lobsters and shrimps), many of which have become highly modified for a variety of functions

Phylum Chordata

including invertebrate chordates, fishes, amphibians, reptiles, mammals, and birds; have the following 4 anatomical features at some point in life: 1) notochord (a flexible, but fairly stiff, fluid-filled rod of cartilage - provides support over the length of the animal - intervertebral disks are remnants of our notochord), 2) dorsal hollow nerve cord (develops into the brain and spinal cord in us), 3) pharyngeal slits (openings in the pharynx that allow water entering the mouth to exit the digestive tract without continuing down the rest of the digestive tract - they function in filter feeding in invertebrate chordates, and the slits and their supporting structures have become modified for gas exchange, jaw support, hearing and other functions during evolution), 4) muscular, postanal tail (used for propulsion in many species); 3 subphyla exist

Class Monocotyledones

including orchids, bamboos, palms, lilies, yuccas, and grasses (such as corn, wheat, and rice); one cotyledon (embryonic seed leaf) present; leaf venation is parallel; vascular bundles are scattered within the stem; fibrous (small and highly branched) roots are present; floral parts occur in multiples of 3

Class Arachnida

including scorpions, spiders, ticks, and mites; cephalothorax has six pairs of appendages, the chelicerae, the pedipalps (function in sensing or feeding), and 4 pairs of walking legs; the abdomen in arachnids lacks appendages; nearly all ticks are blood-sucking parasites on the body surfaces of reptiles, birds, or mammals; parasitic mites live on a variety of invertebrates and vertebrates; spiders use their fanglike chelicerae, equipped with poison glands, to attack prey; as the chelicerae chew the prey, digestive juices are spilled onto the torn tissues, softening the food and allowing the spider to suck up the liquid prey; spiders carry out gas exchange using book lungs (stacked plates which contain a central chamber - extensive surface area for gas exchange); many spiders spinnerets which spin fibers of silk produced by their silk glands into webs, droplines, cloth covering for eggs, or into "gift-wrapping" for food that males offer females during courtship

Phylum Echinodermata

including sea stars, brittle stars, sea urchins, sea lilies, and sea cucumbers; name means "spiny skin"; radial (really pentaradial) symmetry as adults, bilateral as larvae; thin skin covers an endoskeleton of hard calcareous plates (CaCO3); most are prickly from skeletal bumps and spines that have various functions; all possess the unique water vascular system, a network of hydraulic canals branching into extensions called tube feet, which they use for locomotion, feeding, and gas exchange; most have an oral surface (contains mouth), which faces the substrate, and an aboral surface, which faces upward (contains anus); 6 classes exist (all marine)

Order Euphausiacea

krill; pelagic, shrimp-like malacostracans; filter feeders; famous for being the prey of baleen whales; live in huge schools

Candidate Kingdom Archaezoa

lack mitochondria (evolved before the endosymbiotic event which formed mitochondria); one subgroup is the diplomonads, which have flagella, 2 nuclei, no plastids, and a simple cytoskeleton (Giardia lamblia causes giardiasis, with symptoms of severe diarrhea and cramping - transmitted in water with contaminated human feces)

Class Hirudinea

leeches; most inhabit fresh water; blood-sucking parasites on other animals; range from 1 to 30 cm long;use either bladelike jaws to slit the skin of the host, or secrete enzymes to digest a hole through the skin (usually not felt because an anesthetic is also secreted); the leech also secretes a chemical called hirudin, which keeps the blood of the host from coagulating - the leech then sucks as much blood as it can hold (often more than 10 times its weight - can then last for months without another meal); once used by physicians for bloodletting; still used for treating bruised tissues and for stimulating circulation to fingers or toes that have been sewn back after an accident

Extreme halophiles

live in saline places such as the Great Salt Lake and the Dead Sea; some actually require an environment ten times saltier than seawater to grow, whereas others merely tolerate high salinity; colonies are often purple-red in color, due to bacteriorhodopsin (built into plasma membrane and used to absorb light - energy absorbed is used to pump protons, driving ATP synthesis - this is the simplest method of photophosphorylation known)

Division Hepatophyta

liverworts (previously classified in the Division Bryophyta, along with mosses and hornworts); body is divided into lobes, reminding some of the lobed liver of an animal; reproduce asexually from little bundles of cells called gemmae, which are bounced out cups (gemmae cups) on the surface of the gametophyte by raindrops; nonvascular plants

Order Stomatopoda

mantis shrimps; possess a pair of greatly enlarged, anterior thoracic appendages which are used for raptorial feeding (can't be kept in glass tanks because of these)

Class Diplopoda

millipedes; wormlike body with distinct head bearing antennae and chewing mouthparts; segmented body with 2 pairs of walking legs per segment; herbivorous, eating decaying leaves and other plant matter; may have been among the earliest animals on land, living on mosses and primitive vascular plants

Division Bryophyta

mosses; mosses, along with liverworts and hornworts, were all once placed in the Division ________ - but we now recognize enough differences to place liverworts and hornworts in their own divisions, although all 3 groups are still collectively called __________; the gametes within all _________ develop within gametangia; the male gametangium is called an antheridium, and produces flagellated sperm; in the female gametangium, the archegonium, one egg is produced; the egg is fertilized in the archegonium, and the zygote develops into an embryo within the protective jacket of the female organ; all _________ are tied to water, for the following reasons, 1) flagellated sperm must swim to egg, 2) they lack vascular tissue (nonvascular plants) - rely on diffusion, capillary action and cytoplasmic streaming to slowly move water up the plant; bryophytes lack lignin-fortified tissue for support, so they must remain close to the ground and grow as a carpet of mat (support each other) - most only 1 - 2 cm tall; the haploid gametophyte stage is the dominant stage in the life cycle of a bryophyte (sporophyte is dominant in all other plants); the sporophyte is smaller and shorter lived in bryophytes, and depends on the gametophyte forr water and nutrients; the diploid sporophyte produces haploid spores by meiosis in a structure called a sporangium - the spores then disperse, germinate, and grow by mitosis into new gametophytes; mosses have "leaves", "stems", and "roots" (rhizoids) which are not homologous to those of land plants because they lack vascular tissue; mosses support each other by growing as a mat or carpet; each individual grips the substratum with its rhizoids (do not extract water with these, so are not true roots)

Gram-positive bacteria

most are gram-positive, chemoheterotrophs; many, including Clostridium and Bacillus, form endospores that are resistant to harsh conditions; among those not forming endospores are mycoplasmas, the smallest known cells (0.10 - 0.25 m) - the only known bacteria that lack cell walls (so are gram-negative, but closely related to Clostridium), they are common in soil, but some are pathogenic in animals (Mycoplasma pneumoniae causes "walking pneumonia" in humans); gram-positive bacteria also include the actinomycetes, soil bacteria that produce branching colonies resembling fungi (many, such as Streptomyces, are important sources of antibiotics)

Class Copepoda

most are marine, and many are parasitic, particularly on fish; most abundant zooplankton (and therefore, probably the most abundant

Order Isopoda

most are marine, but many ("rolie polies" or sow bugs) are terrestrial; body is dorsoventrally flattened; carapace is absent; named for the fact that there is little specialization among their appendages (legs look the same)

Kingdom Protista

most diverse kingdom, due to the fact that it is polyphyletic (includes members derived from 2 or more ancestral forms not common to all members, and thus does not reflect phylogeny); thus, the 5-kingdom system is probably now obsolete; protists, based on sequencing data, can probably divided into the following 5 "candidate kingdoms", which have not yet been formally recognized

Class Dicotyledones

most flowering plants; examples include roses, beans, maples, oaks, and sunflowers (among many others); 2 cotyledons present; leaf venation is branching; vascular bundles are arranged in a ring within the stem; usually a large taproot present; floral parts occur in multiples of 4 or 5

Kingdom Animalia

multicellular, heterotrophic eukaryotes; lack cell walls - bodies held together by structural proteins, such as collagen; unique types of intercellular junctions are often present (tight junctions, gap junctions, and desmosomes); only animals have nervous and muscular tissue; animals usually reproduce sexually, with diploid stage dominant - usually a small flagellated sperm fertilizes a larger, nonmotile egg, producing a diploid zygote; the zygote then undergoes cleavage (a succession of mitotic divisions) - the early, solid ball of cells formed via cleavage is called a morula - continued cell division (blastulation) leads to the formation of a blastula, a hollow ball of cells (the hollow cavity is called a blastocoel) - following the blastula stage is gastrulation, during which the 3 primary germ (tissue) layers are produced (differentiation occurs as cells migrate across the dorsal lip of the blastopore, an opening formed during gastrulation - the opening leads to the primitive gut, or archenterons - the blastopore later becomes either the mouth in protostomes or the anus in deuterostomes) - the 3 primary germ layers are the ectoderm (becomes skin and nervous system later), mesoderm (becomes muscle, bones, blood, gonads, and the heart later), and endoderm (becomes the organs of the digestive tract, including liver, lungs, stomach, intestines, etc.) - after gastrulation and the formation of the gastrula, only chordates undergo neurulation, the formation of a central nervous system (dorsal hollow nerve cord, which develops into the spinal cord and brain); many animals have a sexually immature larval stage, which undergoes a metamorphosis into the adult form; the Kingdom Animalia can be broken into 2 major branches, the parazoa (means "beside animals - includes sponges, which lack true tissues, or cells that work together) and the eumetazoa (all other animal phyla - possess true tissues); the eumetazoans can in turn be broken down into 2 major branches, the radiata (possess radial symmetry, and only 2 germ layers, ectoderm and endoderm - includes the phylums Cnidaria and Ctenophora) and the bilateria (possess bilateral symmetry, and all 3 embryonic germ layers, ectoderm, endoderm, and mesoderm - contains all more advanced animal phyla); the radiata are said to be diploblastic (2 germ layers), whereas the bilateria are triploblastic (3 germ layers); the triploblastic bilateria can be divided into 3 groups, the acoelomates (solid bodies, no cavity, or coelom, between the digestive tract and outer body wall - includes the Phylum Platyhelminthes, flatworms - acoelomates also lack a complete digestive tract), the pseudocoelomates (body cavity not completely lined by tissue derived from mesoderm - includes the Phylum Nematoda, roundworms, and the Phylum Rotifera, rotifers), and the coelomates (possess a true coelom, a fluid- filled body cavity completely lined by tissue derived from mesoderm - coelom serves to separate the digestive tract from the outer body wall - all higher phyla of animals are coelomates); finally, the coelomate phyla can be divided into 2 distinct groups, the protostomes (mollusks, annelids, arthropods, and a few other minor phyla) and the deuterostomes (echinoderms, chordates, and a few other minor phyla); protostomes and deuterostomes differ in 4 distinct ways: 1) protostomes have spiral cleavage, whereas deuterostomes have radial cleavage (after each round of cleavage, the cells are lined up on top of each other), 2) protostomes have determinate cleavage, whereas deuterostomes have indeterminate cleavage (in determinate cleavage, the fate of each cell is already determined by the 4-cell stage in the embryo, whereas in indeterminate cleavage, each cell in the early embryo retains the capacity to develop into a complete embryo - can lead to identical twins), 3) protostomes have schizocoelous coelom formation (coelom forms by splitting open solid blocks of mesoderm), whereas deuterostomes have enterocoelous coelom formation (coelom forms by mesoderm budding off from the wall of the archenteron), and 4) in protostomes, the blastopore becomes the mouth of the organism (hence the name "first mouth"), whereas in deuterostomes, the blastopore becomes the anus

Order Mysidacea

mysid (opossum) shrimps; benthic or pelagic shrimps; possess a ventral marsupium (pouch) for brooding the eggs

Green Algae

named for the color of their chloroplasts, some systematists place them within the plant kingdom, whereas others advocate close relationship, but not inclusion with plants (they were considered algae in the Division Chlorphyta in previous classifications); have same pigments as plants (chl a, chl b, and carotenoids), and store food the same way (as starch); most live in freshwater (some marine); some are unicellular (Chlamydomonas), some are multicellular (Ulva - sea lettuce), some are colonial (Volvox), and some are coenocytic (many nuclei, but one cell - Codium, deadman's fingers, is an example)

Chlamydias

obligate intracellular parasites that obtain all their ATP from host cells; lack peptidoglycan; Chlamydia trachomatis is the most common cause of blindness in the world and also causes the most common form of sexually transmitted disease (nongonococcal urethritis) in the U.S.

Cyanobacteria

photoautotrophs with plant-like photosynthesis (use 2 photosystems to split water, yielding O2 as a byproduct); most live in freshwater, but some live in ocean, and some live as symbionts with fungi on land (lichens); some can fix nitrogen

Kingdom Plantae

plants are multicellular eukaryotes that are photosynthetic autotrophs; cell wall made of cellulose;store surplus carbohydrate in the form of starch (either amylose or amylopectin); chl b is present as an accessory pigment (all photosynthetic eukaryotes also have chl a, the pigment directly involved in the conversion of light to chemical energy); most are terrestrial organisms (some have secondarily returned to water); gases are exchanged through stomata in most plants; most have a waxy cuticle to prevent water loss; produce secondary products such as poisons, lignin (hardening compound in the cell walls of "woody" plants), and sporopollenin (tough compound found in walls of spores and pollen); gametes produced within gametangia, organs with protective jackets of sterile cells that protect the gametes and developing embryo from drying out during development (not present in algae); undergo alternation of generations between a diploid sporophyte stage and haploid gametophyte stage; most have vascular tissue, but a few nonvascular plants (bryophytes) exist; the vascular plants can be split into seedless plants and seed plants; within the seed plants, 2 major groups exist: gymnosperms ("naked seed" - no fruit around seeds) and angiosperms (fruit covers seeds)

Phylum Nemertea

proboscis or ribbon worms; probably related to the protostome coelomates, although their phylogenetic position is still being debated; structurally acoelomate, but has a small, fluid-filled sac thought to be homologous to the coelom of protostomes; the sac and its fluid hydraulically operate an extensible proboscis, which is used to capture prey; range in length from 1 mm to more than 30 m; most are marine; similar to flatworms in terms of excretory, sensory, and nervous systems, but possess 2 features not found in flatworms: a complete digestive tract and a closed circulatory system (blood is contained within vessels); they have no heart, so blood is propelled by muscles squeezing the vessels

Phylum Nematoda

roundworms (nematodes); like rotifers, they are pseudocoelomate members of the bilateria; range from 1 mm to 1 m in length; found in most aquatic habitats, wet soil, and in the body fluids of plants and animals; they are covered by a tough cuticle; like rotifers, they are small enough that they do not need a circulatory system (diffusion works for gas exchange); possess longitudinal muscles (run length of body), which allow them to move with a thrashing motion; they inhabit moist soil and the bottoms of lakes in huge numbers, playing an important role in decomposition; many are parasites, including various pinworms and hookworms; one example is Trichinella spiralis, the cause of trichinosis - humans acquire this nematode by eating undercooked infected pork (which contains juvenile worms encysted in the muscle tissue) - within the human intestine, the juveniles develop into sexually mature adults, the females of which burrow into the intestinal muscles, producing more juveniles - these juveniles bore through the body or travel in lymph vessels to encyst other organs, including muscles

Class Holothuroidea

sea cucumbers; lack spines and the endoskeleton is very much reduced (composed of a few scattered ossicles); sea cucumbers are elongated in the oral- aboral axis, giving them the shape for which they are named (take an urchin and stretch it then lay it on its side, and you have a sea cucumber); 5 rows of tube feet are present; some of the tube feet around the mouth are developed as feeding tentacles; most are deposit feeders; many can eviscerate there guts when threatened - they later regenerate their lost digestive

Class Crinoidea

sea lilies and feather stars; sea lilies are sessile, whereas feather stars crawl using their long, flexible arms; all ________ use their arms in suspension (filter) feeding; oral surface is directed upward, unlike other echinoderms; this is probably the most ancient class, and its members have not changed much in 500 million years; can have 50 or more arms

Class Asteroidea

sea stars; usually 5 arms radiating from a central disk; use their abundant tube feet for locomotion, adhering to rocks, or for creating suction when opening the shells of their prey (bivalves usually); evert stomach through mouth and insert into the prey (once the shell has been opened a mm or two) - once inside, the stomach secretes digestive juices which dissolve the prey (within its own shell); capable of regeneration

Class Echinoidea

sea urchins and sand dollars; no arms, but still have 5 rows of tube feet for locomotion; have muscles that can pivot their spines, assisting their slow movement; their mouth (on the oral surface - facing down) is ringed by a complex jawlike structure called Aristotle's lantern, which is used to bite off pieces of algae; sand dollars differ from urchins in that they are flatter and have shorter spines

Phylum Porifera

sponges ("pore bearers"); lone members of the parazoa (no tissues - cells are unspecialized); draw water through pores into a central cavity called the spongocoel - the water the flows out of the sponge through a larger opening called the osculum; most sponges are filter (suspension) feeders, using flagellated choanocytes (collar cells) to create water currents, trap food particles, then phagocytose them; body consists of 2 cell layers separated by a gelatinous layer called the mesohyl - wandering through the mesohyl are ameobocytes, which take up food and water from the choanocytes, digest it, and carry nutrients to other cells; amoebocytes also account for the support of a sponge by producing spicules (made of CaCO3 or silica) or spongin (a type of collagen)

Class Cestoidea

tapeworms; adults live mostly in vertebrates; the tapeworm head, or scolex, is armed with suckers and hooks that allow it to attach to the intestinal lining of its host; posterior to the scolex is a long ribbon of units called proglottids, which are little more than sacs of sex organs; lack a digestive tract (absorb food that has been predigested by their host - absorption is directly across their body wall); in a typical tapeworm life cycle, mature proglottids release thousands of eggs, which leave the human along with the feces - human feces contaminate the food or water of intermediate hosts, such as pigs and cattle, developing into larvae that encyst in the muscles of these animals - humans acquire the larvae by eating undercooked meat contaminated with the cysts, and the worms then develop into mature adults within the intestine of the human - can reach 20 m in length, robbing the human host of nutrients, causing nutritional deficiencies

Molds, Yeasts, Lichens, and Mycorrhizae

these 4 fungal lifestyles have evolved independently in the zygote fungi, sac fungi, and club fungi; a mold is a rapidly growing, asexually reproducing fungus - they grow as saprobes or parasites - examples of molds include bread mold (a zygomycete) and Penicillium (ascomycete species - some produce the antibiotic penicillin, others are important fermenters of blue cheese such as roquefort, Brie, and Camembert, producing the unusual colors and flavors associated with these cheeses) - other molds produce other antibiotics; yeasts are unicellular fungi that inhabit liquid or moist habitats, including plant sap and animal tissues - humans use yeasts to raise bread (produce CO2 during fermentation) and to ferment alcoholic beverages - the most important of all domesticated fungi is Saccharomyces cerevisiae, available as many strains of baker's and brewer's yeast - the carbon dioxide they produce leavens dough, and they ferment sugars to alcohol during alcoholic beverage production; lichens are mutualistic associations of millions of photosynthetic organisms (green algae or cyanobacteria) held in a mesh of fungal hyphae (commonly an ascomycete, but sometimes a basidiomycete) - the fungus provides a suitable environment of growth, and in exchange receives sugars or fixed nitrogen (from the algae or cyanobacteria, respectively) - lichens are important pioneers during ecological succession - many can tolerate extreme cold, but they do not stand up well to air pollution; mycorrhizae are mutualistic associations between a fungus and a plant root - the plant provides sugars to the fungus, whereas the fungus provides increased surface area for absorption to the plant; truffles are the underground fruiting bodies (ascocarps) of mycelia that are mycorrhizal on the roots of trees - they produce strong odors that are attractive to mammals and insects, which excavate them and disperse their spores - traditionally, humans used pigs to find them, but now dogs are used because they have the nose for the scent but not the fondness for the flavor

Extreme thermophiles

thrive in hot environments (60 - 105 C), such as hot sulfur springs in Yellowstone (Sulfolobus obtains energy by oxidizing sulfur) and in water near deep-sea hydrothermal vents; some think they are the prokaryotes most closely related to eukaryotes

Phylum Rotifera

tiny animals, ranging in size from 0.05 to 2.0 mm; are pseudocoelomate members of the bilateria, and thus possess a complete digestive tract (mouth, anus, and other organs in between); fluid-filled pseudocoelom (not completely lined with mesoderm) acts as their hydrostatic skeleton; rotifer means "wheel-bearer", a reference to their crown of cilia that draws a vortex of water into their mouth; just posterior to the mouth, a region of their digestive tract called the pharynx bears jaws that grind food (mostly microorganisms suspended in the water); most reproduce by parthenogenesis (females produce more females from unfertilized eggs)

Phylum Phoronida

tube-dwelling marine worms ranging from 1 mm to 50 cm in length; some lived buried in the sand within tubes made of chitin, extending their lophophore to feed

Methanogens

use H2 to reduce CO2 to methane (CH4), obtaining energy; strict anaerobes (poisoned by oxygen); live in swamps and marshes where other microbes have used up the oxygen; some inhabit the anaerobic guts of animals, playing an important role in the nutrition of cattle, termites and other herbivores that subsist on cellulose

Subphylum Trilobitomorpha

very common in shallow seas throughout the Paleozoic, but went extinct with the great Permian extinctions that ended that era (250 mya); had pronounced segmentation, but their appendages showed little variation from segment to segment (little specialization)

Phylum Onychophora

walking worms; unjointed appendages, but molecular systematics indicates that this phylum is not a missing link between the annelids and arthropods, but rather they are probably true arthropods

Division Zygomycota

zygomycetes or zygote fungi (suffix "mycete" means "fungus"); mostly terrestrial, living in soil or on decaying plant and animal material; some species form mycorrhizae; hyphae are coenocytic (septa are only found where their reproductive cells are formed); named for their zygosporangia, resistant structures formed during sexual reproduction; a common examples is the black bread mold (Rhizopus), whose hyphae permeate bread - they reproduce asexually by producing black aporangia at the tips of upright hyphae (we only see these spore-bearing structures - the hyphae are too small to see easily)