BI 101: Invertebrate Animals Announcements

Transcription

1 BI 101: Invertebrate Animals Announcements Quiz #6 Friday Plants: Gymnosperms & Angiosperms Don t forget the prelab just the front page I have another lab to substitute the one in the packet--- food web of the compost pile! Bring compost! The three-domains Classification CHLOROPHYTA AMOEBOZOANS (Forams and Radiolarians) Rhizarians Rhodophyta Alveolates Stramenopile Euglenozoa Bacteria Archaea Eukarya The six-kingdom system Bacteria Archaea Protista Plantae Fungi Animalia The traditional five-kingdom system Monera Protista Plantae Fungi Animalia Animal Cell Evidence indicates that animals evolved from choanoflagellates (protists) ~ 570 mya Single cells Often clonal Heterotroph No specialization or coodination between cells Fungus Cell 1

2 What are some characteristics animals share? List as many as you can think of. Discuss this in your groups What is the difference between vertebrates and invertebrates? Animal Classification Symmetry 1. DNA sequencing 2. Body Symmetry 3. Presence or absence of body cavity 4. Embyonic Development Body Cavity Body Cavity? Most bilateral animals have body cavities Body cavities are fluid-filled cavities between the digestive tube and the outer body wall Functions: skeleton, providing support for the body and a framework against which muscles can act protective buffer between the internal organs and the outside world They can allow organs to move independently of the body wall A No coelom (acoelomate animal) epidermis organs packed between gut and body wall gut cavity Fig. 25-4a, p

3 Body Cavity? Body Cavity? epidermis gut cavity epidermis gut cavity B Pseudocoel (pseudocoelomate animal) unlined body cavity around gut C Coelom (coelomate animal) body cavity with a lining (dark blue) derived from mesoderm Fig. 25-4b, p. 405 Fig. 25-4c, p. 405 Protostomes Embryonic Development Blastopore forms mouth first Deuterostomes Blastopore forms anus first Porifora - sponges Sponge Anatomy (water flow out of the sponge) epithelial cell pore spicules (water flow into the sponge) Sessile (Larva motile) No true tissues or organs Exhibit asymmetry or radial symmetry Filter feeders amoeboid cell pore cell collar cell (water flow) Fig

4 Sponge filtration/feeding Sponges for Breast Cancer Research! The artificial component called eribulin mesylate imitates an element found in sponges. Collar Cell Collar Cell watch?v=t7e1rq7zhlc&feat ure=player_embedded =29W77870BgE&list=PLVN5247pO BYcE1Mn_pWHIL9l0sMIx19TI It can check cell division, which is a reason of cells to self-damage. Cnidaria Sea Anemone Radial symmetry Two tissue layers Filled with water supports body Nerve net Nematocysts -stinging organelles that release toxins Cnidarian Weaponry: The Cnidocyte trigger filament Cnidaria: Symbiosis Coral is a mutualism between photosynthetic dinoflagellates (protist) and a cniderian (animal) Algae in coral called zooxanthelle trigger nuclei (b) Cnidocytes Fig

5 In many coral species polyps form colonies Cnideria video Colonial polyps secrete a hard external skeleton of calcium carbonate The skeleton remains after the polyp dies New polyps build on the skeletal remnants of earlier generations Platyhelminthes - flatworms Bilateral symmetry 3 tissue layers Cephalization (nerve mass) True organs and organ systems Aceolomate (no body cavity) Parasitic forms but some free living Mollusca Characteristics: Evolved ~500 mya bilateral symmetry Coelomates- true body cavity Unsegmented aquatic & terrestrial possess all organ systems 5

6 Mollusca Diversity 2 nd most diverse animal group: 93,000 species Gastropods 80% of mollusk species Snails Slugs Nudibranchs Cephalopods Most neurologically advanced Marine predators Octopus Squid Cuttlefish Bivalves Aquatic Clams Mussels Nudibranchs 3,000 described species Snails without a shell Unique lifestyle and defense mechanisms Elysia the photosynthetic animal (video) Glaucus atlanticus consumes man of war jellyfish and puts the nematocytes on its own back! Nudibranchs The Blue Dragon, Pteraeolidia ianthina, has a symbiosis with dinoflagellates. It also steals the armed tentacles of a sea anemone, a Cniderian, for defense and combat! Annelida - segmented worms Fig Segmented body Bilateral symmetry 3 tissue layers Coelom (fully enclosed body cavity) Organ systems are more fully developed Decomposers and Parasites (a) Coelomate Coelom Digestive tract (from endoderm) Pseudocoelom (b) Pseudocoelomate Digestive tract (from endoderm) Body covering (from ectoderm) Body covering (from ectoderm) Tissue layer lining coelom and suspending internal organs (from mesoderm) Body covering (from ectoderm) Muscle layer (from mesoderm) Tissue- Annelida - segmented worms Class: Polychaetes Each segment with many hairlike chetae 12,000 species Mostly marine Class: Clitellata Earthworms - Oligochaete 10,000 species Terrestrial Decomposers Leeches Hirudinea 700 species Predators or parasites Most freshwater 6

7 Arthropoda Earth s most diverse phylum Billions of species! Major groups: Crustaceans Myriopods Arachnids Hexapods Arthropoda Characteristics 1. Exoskeleton= External skeleton 2. Specialized body segments 3. Jointed appendages 4. Bilateral symmetry 5. True coelom (body cavity) Arthropoda respiratory system: Trachea Arthropoda respiratory system: Example: Grasshopper Spiracles: pores in exoskeleton Trachea: connect to spiracles, carry oxygen to the body cells Arthropoda respiratory system 7

8 Arthropod Phylogeny 8 legs Arachnids spiders, Mites Ticks scorpions Horseshoe crabs Pseudoscorpians Chelicerata Arthropod Phylogeny Rolly pollies Isopods Lobsters Crayfish Crabs Shrimp Krill Baracles Crustaceans Arthropod Phylogeny Myripoda Class: Symphyta Class: Chilopoda (centipedes) Class: Diplopoda (millipeds) 8

9 Collembola Protura Diplura Collembola Protura Diplura Archaegnatha Slverfish: Thysanaura 6/3/2013 Arthropod Phylogeny Arthropod Phylogeny Insecta Wings! Hexapoda: Reduction in body segments to 3 Reduction in legs to 6 Insecta: mouthparts outside head capsule Hexapoda: Reduction in body segments to 3 Reduction in legs to 6 Figure Segments are fused and specialized in insects Specializations for Feeding abdomen thorax antennae head compound eye mouth parts Grasshoppers (a) mouth has numerous manipulating and shearing parts for eating vegetation. Flies (b) has a labium mouth part that has a sponge like end for absorbing nutrients from moist foods. wing Butterflies & Moths (c) mouth part is a tube like maxilla for sucking up nectar from flowers. Mosquitoes (d) have a stylus for piercing their prey to draw blood like a hypodermic needle. Announcements Insect Development Final exam next Monday 1-3pm Study guide up on website Final quiz this Friday: invertebrate animals! Study sessions? 9

10 Discussion Why might it be advantageous for insects to have complete metamorphosis? Fig Nematoda - Round worms Exoskeleton (molts) body coved in a thick cuticle Psuedocoelom (false body cavity) Bilateral worms 3 tissue layers Unsegmented Parasitic (50%) and free-living (50%) (a) Coelomate Coelom Digestive tract (from endoderm) Pseudocoelom (b) Pseudocoelomate Digestive tract (from endoderm) Body covering (from ectoderm) 25,000 species Tissue layer lining coelom and suspending internal organs (from mesoderm) Body covering (from ectoderm) Muscle layer (from mesoderm) A Freshwater Nematode ovary vagina eggs mouth cuticle posterior end intestine anterior end Fig Discussion questions 1. How do earthworms differ from tapeworms and planarians? 2. How do earthworms differ from nematodes? 10

11 Phylum Echinodermata 6,000 species Includes sand dollars, sea urchins, sea stars, sea cucumbers, and sea lilies Echinodermata characteristics 1. Deuterostomes Echinodermata characteristics 2. Larvae exhibit bilateral symmetry; adults show radial symmetry Echinodermata characteristics 3. Endoskeleton (internal skeleton) that sends projections through the skin Composed of calcareous plates or ossicles Echinodermata characteristics 4. Water vascular system: Food and waste transport Respiration Locomotion 11

12 Discussion question How do sea urchins and sea stars differ from sea anemones and coral? VS Phylum Chordata Contains both vertebrates AND invertebrates! Ancestral Animal Diversity Derived Radial Symmetry Bilateral 0, 2 # of tissue layers 3 All Chordates share four characteristics: 1. Dorsal nerve cord 2. Notochord (Primitive skeleton) 3. Pharyngeal gill slits 4. Post-anal tail 1 Acoelomate, Pseudocoelomate Protostome # gut openings Type of coelom Type of development 2 Eucoelomate Deuterostome Ancestral Animal Diversity Derived Radial 0, 2 1 Acoelomate, Pseudocoelomate Protostome Symmetry # of tissue layers # gut openings Type of coelom Type of development Bilateral 3 2 Eucoelomate Deuterostome 12