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| Metazoans | The animal kingdom. There are 30 extant phyla and 15 extinct. Characterized by collagen, heterotrophy, early embryo forming a blastula, sex cells formed in special organs, sperm w whiplike tails |
| Most ancestral metazoans? | Sponges are the most ancestral. They LACK: Cell layers, tissues, nervous system w/ neurons |
| Chordata | Deuterostomes (key metazoan split). Includes cephalochordata (amphixous), Urochordata (tunicates), and Vertebrates |
| 4 features of chordates | 1. Notochord (rod-like trait, extends the length of animal on dorsal surface, provides rigidity) 2. Dorsal hollow nerve cord (parallel/adjacent to notochord, on one end is brain) 3. Segmented muscular post-anal tail (sometimes lost in development) 4. Endostyle (groove in pharyngal region, secretes mucous for feeding in adult ufo/cephalochordates and non-adult verts before it becomes thyroid gland) |
| Blastula | Early embryo of metazoans forms a hollow ball of cells called a blastula, which multiplies into various organs. Forms endo/meso/ectoderm. |
| Flatworms | In flatworms we first see: organs, three cell layers, bilateral symmetry, and movement as an adult |
| Deuterostomes vs. Protostomes | Major metazoan split: In the protostome gastrula, the blastopore becomes the mouth. In Deuterostome development, the blastopore becomes the anus, and invagination becomes mouth. |
| Protostomes include: | Arthropods, annelids, mollusca (which develop complex social behavior and large size, i.e. octopi) |
| Deuterostomes include: | Chordata (uro/cepahlochordates & vertebrates); Hemichordata, Echinodermata (starfish) |
| More about tunicates (Urochordata) | Larvae have notochord/nerve cord, mobility, and tail. Adults have endostyle, are immobile, secrete a hard casing, and filter-feed. |
| More about Cephalochordates (amphioxus aka lancelets) | Active larvae, sedentary adults. Myomeres for swimming, notochord, pharyngeal slits without gill tissues for O2 |
| Cephalochordates have similarities to verts but not urochordates: | Pharyngeal slits, dorsal aorta, ventral "heart," excretory cells (like kidney) |
| Vertebrates have | Vetrebrae; cranium; hox. duplication; neural crest (4th germ layer, quadroblastic); tripartate brain (hind, mid and forebrain); larger body size and activity; specialized systems |
| Vertebrate specialized systems (overview) | Systems accomplish what diffusion and cilia do in non-vertebrates; organ systems for faster physiological processes; muscle/skeleton = mobility; sensory systems; protective integument |
| Tissue layers: Ectoderm | Outermost layer, gives rise to the epidermis, linings of most anterior and most posterior parts of digestive tract; nervous system including most sense organs |
| Tissue layers: Endoderm | Innermost layer. Forms the rest of digestive track lining, lining of glands associated w gut; most respiratory surfaces of gills and lungs |
| Tissue layers: Mesoderm | Middle layer. Forms all else, including muscles, skeleton, connective tissue, circulatory/urogenital systems |
| Mesoderm splits to form what? | The coelom, which contains internal organs. The pleuroperitoneal cavity = around viscera; pericardial cavity = around heart |
| Tissue layers: Neural crest | Forms many structures in anterior head, most of PNS (periferal nervous system) and brain |
| Pharyngeal pouches | At least fleeting appearance in all verts. Fish: between-pouch grooves perforate to become gill slits. Land-verts: grooves disappear in adults |
| Dorsal Hollow Nerve Chord | Formed by infolding, pinching off of long ectoderm ridge dorsal to notochord. Neural crest cells arise next to developing nerve cord, then later disperse |
| 3 Segments of Embryonic Mesoderm: Somites | Dorsal and above gut wall (segmental). Dermis of skin, striated muscle for locomotion, vertebral column/part of back skull, striated muscle on underside of body after migration |
| 3 Segments of Embryonic Mesoderm: Lateral Plate | Ventral, surrounding gut, containing coelom (unsegmental). Connective tissue, vasc. system, mesentreries, lining of coelomic cavities, repro system, smooth (of gut) and cardiac muscle |
| 3 Segments of Embryonic Mesoderm: Nephrotomes | Small segmental buds linking somites and lateral plate. Kidneys, kidney drainage ducts, gonads |
| 5 adult tissue types (form organs, which have all types) | Epithelial, connective, vascular (blood), muscular, nervous |
| Collagen | Fibrous protein, main component of most tissues |
| Keratin | Primarily ectodermal, mostly in epidermis of tetrapods |
| Integument | Skin and derivatives (glands, scales, dermal armor) |
| Mineralized tissue (6 types) | Hydroxyapatite (Calcium/Phosphorous). Enamel, dentine and bone (min. only in adults); Cartilage (unmin. in most verts but mineralized in sharks); enameled; cementum |
| Bone | 2 types (dermal and endochondral). Dermal in most verts (product of dermis). Endochondral bones make up most of skeleton (long bone). Bone is vascularized and can re-build itself |
| Cranial skeleton (skull) | Chondocranium (surrounding brain); splanchnocranium (forming gill supports); dermatocranium (forming in skin as an outer cover) |
| Cranial muscle | Extrensic eye muscle (innervated by somatic motor nerves); branchiomeric muscles (feeding and respiration - hugely altered in mammals expc primates for suckling and facial expressions) |
| Axial skeleton (muscles/skeleton that run along vertebral axis) | Notochord (dordal stiffening rod); axial muscles: myomeres (folded and extended over multiple segments to allow motion), exaxial (above central axis) and hypaxial (below central axis) in jawed verts |
| Feeding and digestion | Early verts probably filtered particles from the water. Most verts are particulate feeders, who secrete digestive enzymes. Non-vertebrate Amphioxus digests within gut cells. Primitive verts have no stomach, no intestinal division |
| Respiration and ventilation | Probably across skin for ancestors (gills for water, lungs for air) |
| Cardiovascular system | Transport of nutrients, O2/CO2, waste, hormones. Helps maintain homeostasis |
| Excretory/reproductive system | Formed from nephretomes, which forms nephric ridge. Archinephric duct drains kidney and in jawed verts, testes. Kidney in fish extends length of dorsal body wall |
| 3 portions of vertebrate embryo kidney | Pronephros (functional only in embryos of extant verts); Mesonephros/Metanephros (opisthonephros); adult fish, amphib |
| What is the nephron? | The functional unit of the kidney, which works via ultrafiltration |
| Gonads | Paired, usually on the posterior body wall |
| Vertebrate egg production | Nearly continuous in humans, seasonal in most verts. Once in many fishes and some mammals (called semelparous) |
| Gamete passage? | Primitive and extant jawless verts have no special duct. Jawed verts: males = sperm into archineprhic duct; females = egg releaced into coelom and then transported by oviduct |
| Nervous system unique to verts? | Vertebrates have a dual nervous system w/ somatic and visceral |
| Somatic vs. Visceral | Somatic (voluntary): aware of movements (2 parts: sensory to process info/stimuli; motor for behavioral or physiological output). Visceral (involuntary): automatic (motor): sympathetic and parasympathetic, plus sensory |
| Ancestral roles of brain parts | Forebrain = smell; Midbrain = vision; Hindbrain = balance/vibration detection |
| How many cranial nerves in verts? | 10 in ancestral, 12 in amniotes |
| Sense organs | 5 senses of derived verts, plus electroreception in fish |
| Endocrine system | Specialized glands release signals (hormones) into blood stream |
| What kind of feedback characterizes the vert endocrine system? | Negative feedback, in which the hormone that is produced in the loop will eventually shut it off |
| Hormone types | Can be amino acid (protein) hormones, which bind to the outsides of cells, or steroid derived hormones, which bind to the inside of the cell and impact transcription/protein production |
| How do hormones travel? | They travel passively via circulation, and are metabolized/excreted rapidly |
| Hormones impact on behavior? | Hormones modulate the probability or magnitude of behavior, but rarely trigger a behavior. They an also mediate life-history tradeoffs |
| The two Pituitary glands | Posterior and anterior, totally different in affect and origin. |
