Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Aquatic locomotion wikipedia , lookup
History of zoology (through 1859) wikipedia , lookup
Anatomical terms of location wikipedia , lookup
Anatomical terminology wikipedia , lookup
Regeneration in humans wikipedia , lookup
Drosophila embryogenesis wikipedia , lookup
Precambrian body plans wikipedia , lookup
Today’s Plan: 4/20/10 Bellwork: Test Q&A (15 mins) Animals and Behavior test (the rest of class) If you finish early, work on labs or animal summary chart Today’s Plan: 11/13/09 Continue with animals (15 mins) AP Lab 11 (45 mins) Finish Animals notes (the rest of class) Animal Development and Phylogeny Animals: Are multicellular Are consumers Are eukaryotic Are motile at some point in their development Reproduce sexually (some are parthenogenic) Develop from embryos Have a variety of evolutionary advances Symmetry and Body Plans 2 main body plans: invertebrate and vertebrate Of the 2, invertebrate has the most variation Some are asymmetric Those which have symmetry, exhibit 1 of2 types : Radial-may have top and bottom (oral and aboral sides), but can pass a plane through the body in any direction and make 2 equal, identical parts Bilateral-have dorsal and ventral as well as posterior and anterior ends. May exhibit cephalization. Can pass a plane through the body in only one place to make 2 equal, identical parts Figure 32-5 Asymmetry Sponge No plane of symmetry Radial symmetry Jellyfish Multiple planes of symmetry Bilateral symmetry Lizard Single plane of symmetry Posterior Anterior Why Symmetry? In general, the most primitive organisms are asymmetric, slightly more advanced are radially symmetric, and the most advanced are bilaterally symmetric What’s the significance of symmetry? Indicator of health Serves the organism’s function Sometimes redundancy of parts Sometimes directed nervous response The Animal Family Tree The most primitive animals are conglomerations of cells with little specialization and no true tissues Slightly more advanced animals have cells organized into distinct tissues, but no organ systems or body cavity Diploblastic organisms have only 2 tissue layers (cnidarians and ctenophorans) Triploblastic organisms have 3 tissue layers (bilaterally symmetric organisms) The next group has organ systems, but still no body cavity (acoelomates) Still more advanced organisms develop a body cavity which is unlined (pseudocoelomates) The most advanced organisms develop a body cavity lined in mesoderm (coelomates) In protostomes, coelom forms in mesoderm at the sides of the archenteron (primordial digestive tube) In deuterostomes, coelom forms in the archenteron wall Figure 32-6 Acoelomates have no enclosed body cavity. No coelom Skin (from ectoderm) Muscles, organs (from mesoderm) Gut (from endoderm) Pseudocoelomates have an enclosed body cavity partially lined with mesoderm. Pseudocoelom Skin (from ectoderm) Muscles, organs (from mesoderm) Gut (from endoderm) Coelomates have an enclosed body cavity completely lined with mesoderm. Coelom Skin (from ectoderm) Muscles, organs (from mesoderm) Gut (from endoderm) Family Tree Continued The coelomates are further divided into two groups: Protostomes-”proto”=first, “stome”=mouth, form from spiral cleavage Deuterostomes-”deutero”=second, “stome”=mouth, form from radial cleavage Groups are based on the fate of the Blastopore during gastrulation Figure 32-10 Animalia Bilateria Deuterostoma Protostoma Ecdysozoa Lophotrochozoa Segmentation Acoelom Pseudocoelom Pseudocoelom Radial symmetry Segmen(in adults) tation Growth by molting Protostome development Phylogenetic tree based on similarities and differences in the DNA sequences of several genes from various animal phyla. The bars along the branches indicate when certain morphological traits originated Deuterostome development Coelom Triploblasty (origin of mesoderm) Bilateral symmetry and cephalization Radial symmetry Diploblasty (ectoderm and endoderm) Epithelial tissue Multicellularity Segmentation Figure 32-1-Table 32-1a Figure 32-1-Table 32-1b Figure 22-11 DURING GASTRULATION, EMBRYONIC TISSUES FORM DISTINCT LAYERS. Ectoderm Mesoderm Endoderm Cross section Start of gut Blastocoel Blastopore Whole embryo Blastopore 1. Different regions of the 2. Gastrulation begins with the 3. The blastocoel shrinks 4. The three embryonic frog blastula contain cytoplasmic determinants (signals or transcription factors) that determine their fate during gastrulation. formation of an opening—the blastopore—that extends into the embryo. Cells from the surface move into the interior through the blastopore. as the surface cells continue to move inward, forming the three embryonic tissue layers. tissue layers are formed, ready for organogenesis. The blastopore (future anus in frogs) surrounds a plug of yolk cells. Figure 22-12 Figure 32-8 PROTOSTOMES Cleavage (zygote undergoes rapid divisions, eventually forming a mass of cells) DEUTEROSTOMES 2-cell stage 4-cell stage 8-cell stage Gastrulation (mass of cells formed by cleavage is rearranged to form gut and embryonic tissue layers) Longitudinal section Spiral cleavage Radial cleavage Mouth Pore becomes mouth Anus Coelom formation (body cavity lined with mesoderm develops) Pore becomes anus Gut Gut Coelom Mesoderm Block of solid mesoderm splits to form coelom Cross section Mesoderm Mesoderm pockets pinch off of gut to form coelom Figure 22-8-1 Radial cleavage: Cells divide at right angles to each other. Spiral cleavage: Cells divide at oblique angles to each other. A word about Germ layers “Germ” layers refers to the 3 layers of tissues in most animals. The layers are present at gastrulation during embryonic development Ectoderm is the outermost layer of cells. It gives rise to the nervous system, skin, hair and nails Mesoderm is the middle layer of cells and is the most versitile. It becomes the skeleton, muscles, inner layer of skin, visceral lining, fatty tissues, and circulatory system Endoderm is the innermost layer of cells. It gives rise to the gut and organs associated with digestion and excretion Why a coelom? The most advanced group of organisms have a coelom. What’s its significance? In order for a body cavity to be considered a coelom, it must be lined in mesoderm. Mesoderm sections off parts of the body This leads to segmentation, a great evolutionary advance. Why? Figure 32-7 Hydrostatic skeleton of a nematode Body wall (in tension— creates pressure in fluid) Fluid-filled pseudocoelom (under pressure—creates tension in body wall) Gut Muscles (cause shape change) Coordinated muscle contractions result in locomotion. Muscles relaxed Muscles contracted Muscles contracted When the muscles on one side contract, the fluid-filled chamber changes shape and the animal bends. Muscles relaxed About Animal Classification As before, new molecular data continues to change our views on how animals are grouped into phyla. The bilaterally symmetric animals are particularly messy to classify Our understanding of Hox genes has changed our views on animal embryology There are some points of agreement with respect to classification: All animals share a common ancestor Sponges are the base of the animals family tree Eumetazoa is a clade of animals with true tissues (cnidaria and ctenophora, formerly coelenterata) Most animal phyla belong to the Bilateria clade Chordates and some other phyla belong to the clade Deuterostomia Major Invertebrate Phyla Sponges were formerly called “Porifera” and are organisms that have the following characteristics: Suspension feeding (capturing food from the water as it travels through the body Pores on the outer surface pull in water and send it out through the spongocoel and it’s main opening, the osculum All are hermaphroditic Have a few specialized cells but no tissues: Choanocytes-collar cells that are flagellated for feeding Amoebocytes-mobile cells that have pseudopods and carry nutrients around the body These are now split into 2 phyla: Calcarea Silicea Figure 32-26 Pseudoceratina crassa Eumetazoans This is a clade, consisting of 2 major phyla of diploblastic organisms: Cnidaria (Includes: jellyfish, hydra, sea anemones, etc) Radially symmetrical Tissue layers (2 distinct-epidermis, gastrodermis)-mesoglea in between (jelly) 2 forms-medusa (mouth down, free-swimming), and polyp (mouth up, sessile) Stinging nematocysts for defense and predation (inside the cnidocytes) 1st organisms with a nervous system (primitive-nerve net, no central control) No matter which shape the organism takes, it’s internal cavity is the gastrovascular cavity Food enters the mouth and broken down. Nutrients from the food are absorbed by the surrounding cells and wastes are expelled from the mouth (2-way digestive tract) Ctenophora (Comb Jellies) Look like jellyfish, but move via the 8 rows of cilia on their bodies No cnidocytes/nematocysts, instead use colloblast (specialized mucous cells) secretions to catch and hold onto prey Actually have a nervous control structure called the Apical Organ at one end of the body Figure 32-27 Polyps attach to substrates. Aurelia aurita Medusae float near the water surface. Aurelia aurita Figure 32-18 Motile larval anemone Sessile adult anemone Figure 32-3 Cnidarians and ctenophores are diploblastic. Cnidaria include hydra, jellyfish, corals, and sea pens (shown). Ctenophora are the comb jellies. Ectoderm Endoderm This dark blue comb jelly… …has just swallowed this white comb jelly Figure 32-4 Mouth Tentacles Tubular body Basal disk Captured prey will be transferred to mouth Figure 32-24 Reproductive polyp Feeding polyps (2n) MITOSIS Medusa (2n) Colonies can get very large, with hundreds of polyps Egg (n) Sperm (n) Larva swims via cilia, then settles MITOSIS Zygote (2n) Diploid Haploid Figure 32-28 Pleurobrachia pileus Rows of cilia Sticky tentacles Lophotrochozoans Clade of organisms that have either/or both a crown of ciliated tentacles or a cilliated larvae called a trocophore This includes the flatworms (Platyhelminthes), Rotifers, Molluscs, and annelids Figure 33-11 Lophotrochozoa Ecdysozoa Figure 33-4 Lophophores function in suspension feeding in adults. Trochophore larvae swim and feed. Food particles Water current Anus Mouth Mouth Cilia used in locomotion and feeding Gut Anus Acoelomates Also called the flatworms b/c they have no body cavity and a flattened body First organisms with bilateral symmetry and cephalization (anterior and posterior end) Organisms with a two-way digestive tract or none at all No need for lungs or gills because of the flat body plan (O2 exchange via diffusion) Water-living or parasitic Mostly vermiform (“vermi”=worm) Figure 33-13 Turbellarians are free living. Pseudoceros ferrugineus Cestodes are endoparasitic. Taenia species Trematodes are endoparasitic. Dicrocoelium dendriticum Rotifers Small, freshwater organisms with a ciliated crown Have an alimentary canal with 1-way digestion Some species can reproduce via parthenogenesis and are all female, others produce 2 types of eggs and are parthenogenesis, while others have males only for the purpose of reproduction Figure 33-12 Rotaria rotatoria Corona Mollusca Bilaterally symmetric Muscular Foot (ventral) Mantle (dorsal)-secretes shell, forms mantle cavity Rasping organ called the Radula Coelomates Open circulatory system Primitive kidneys Gills or primitive lungs Eyes for seeing Several ganglia with a more complex nervous sys Examples include snails, slugs, chitons, limpets, bivalves (clams, oysters, mussels, scallops), chambered nautilis, squid, octopus Figure 33-7b Mollusc body plan (internal view) Gill Mantle (secretes shell) Visceral mass (internal organs and external gill) Muscular “foot” Figure 33-15 Scallops live on the surface of the substrate and suspension feed. Lima scabra Most clams burrow into soft subtrates and suspension feed. Water out Siphons Foot Food particles Water in Gill Gills are thin structures for gas exchange. They also trap food particles as water passes through them. Cilia move the particles to the mouth Figure 33-16 Snails have a single shell, which they use for protection. Maxacteon flammea Land slugs and sea slugs (nudibranchs) lack shells. Chromodoris geminus Bright colors warn potential predators of presence of toxins Figure 33-17 Tonicella lineata Figure 33-18 Octopus dofleini Figure 33-4 Lophophores function in suspension feeding in adults. Trochophore larvae swim and feed. Food particles Water current Anus Mouth Mouth Cilia used in locomotion and feeding Gut Anus Annelids 1st organisms with segmentation (metamerism) Closed circulatory system (blood pigments), but gas exchange occurs via osmosis 1-way digestive tract Double nerve cord, 2 ganglia, lateral nerves in each segment (metamere), brain Taste, tactile, light sensation Vermiform Bilaterally symmetric Head (prostomium) and an anus-bearing terminal portion New segments form behind head and are pushed back (like tapeworms) Circular and longitudnal muscles for complex movement patterns-in each metamere Hydrostatic skeleton in each segment Septa cause internal segmentation, but are traversed by the gut and nerves Figure 33-14 Most polychaetes are marine. Alvinella pompejana Chaetae Most oligochaetes are terrestrial. Paranais litoralis Most leeched live in freshwater. Hirudo medicinalis Ecdysozoans Clade consisting of organisms that go through ecdysis (molting) b/c they have exoskeletons Includes the Pseudocoelomates (Nematodes) and Arthropods Figure 33-19 Ecdysozoa Lophotrochozoa Figure 33-5 Nematodes Have round bodies (pseudocoel) Organisms have sphincters to hold in organs Both free-living and parasitic Ex: hook worm, Ascaris, pinworm, trichina worm, dog heartworm Often have complex life styles w/intermediate hosts Often have male and female forms with dimorphism Figure 33-21 Strongyloides species Nematodes Arthropods Arthro=jointed, pod=foot, all have jointed appendages Exoskeleton made of chitin (a protein) and sometimes calcium carbonate Have metamorphosis Bilateral symmetry, open circulation, nervous system like that of annelids Have gills, air tubes, or book gills Have head, thorax, and abdomen (sometimes head and thorax are fused into a cephalothorax Figure 33-7a Arthropod body plan (external view) Tagma Head Thorax Abdomen Jointed limbs Exoskeleton (covers body) Segmented body Figure 33-23 Spider, showing general chelicerate features Dolomedes fimbriatus Posterior region Anterior region Chelicerae Mites are ectoparasitic. Dermatophagoides species Figure 33-24 Deep-sea lobster Enoplometopus occidentalis Red barnacle Barnacles secrete their own shells Carapace Fiddler crab Tetraclita species Uca vocans Compound eyes on stalks Figure 33-23-Table 33-1-1 Figure 33-23-Table 33-1-2 Deuterostomia This is a clade that includes all deuterostome animals The major phyla within this clade are the Echinoderms and Chordates Figure 34-1 Echinoderms Non-metameric adult with radial symmetry Larvae are bilaterally symmetric No head or brain, circular ring and radial nerves Skeleton of embedded ossicles (calcium carbonate) within the dermis Pedicellariae for catching and moving food Water vascular system with tube feet for locomotion One-way digestive tract (sometimes with eversible stomach) Dermal branchae also help with vascularization Usually separate sexes Ex: sea stars, sea lillies, sea urchins Figure 34-2 Figure 34-3 Figure 34-21 Invertebrate Chordates 2 major Phyla: Cephalochordata and Urochordata Widespread Marine Have a notochord at some point in their development Pharyngeal Gill slits Dorsal Nerve cord (tubular) Postanal tail Bilateral Symmetry Segmented muscles in an unsegmented trunk Ventral heart w/ closed circulation Complete digestive system Figure 34-5a Figure 34-5b Figure 34-23 Figure 34-24 Figure 34-7-1 Figure 34-7-2 Vertebrate Chordates Have all of the characteristics of invertebrate chordates, but also have a vertebral column and spinal cord These are also called the craniates-have a head Major Classes include: Myxini-Hagfish Pterromyzontida-Lampreys Chondrichtheyes-Sharks, skates, and rays Osteictheyes (Actinopterygii, Actinistia, Dipnoi)-Bony fish Amphibians-frogs, salamanders Reptiles-lizards, snakes, crocodillians Aves-Birds Mammalia-duh! Figure 34-25 Figure 34-26 Figure 34-27 Figure 34-28 Figure 34-29 Figure 34-35 Figure 34-37 Figure 34-36 Figure 34-38 Figure 34-31 Figure 34-32 Figure 34-33 Trends in Chordate Evolution From plain chordate characteristics to having a cranium From cranium to jaw (made from gills of fish) Tetrapodal body plan (made from fins of fish) Amniotic (membranous) egg-waterproofing Feathers (from scales of reptiles) From oviparity (monotremes) to viviparity (marsupials and eutherians) Figure 34-10 Figure 34-12 Figure 34-14 Figure 34-16 Figure 34-17