Chapter 17

Remember…. D K P C O F G S

Kingdom Animalia General characteristics: – Heterotrophic – Locomotion – Multicellular – Life cycle where adult is diploid – Undergoes sexual reproduction and produce an embryo

Characteristics of Animals Type of body plan Digestive tracts Level of organization Type of body cavity Type of symmetry Skeletal system Reproduction Respiration

Type of Body Plan Sac-Plan – Incomplete digestive system – Gastrovascular cavity Tube-Within-a-Tube Plan – Complete digestive system – Inner tube is digestive system, outer tube is body wall – Two openings

Digestive Tracts Incomplete One opening same opening used to take in food and get rid of wastes GVC Complete Two openings food is ingested at one end wastes from digestion passed out of the tract at the other end

Level of Organization Cellular Only composed of cells Sponges Tissue Composed of cells and tissues Jellyfish Organ Composed of cells, tissues, and organs Us!

Type of Body Cavity Acoelomate – Lacks a body cavity – Tissues packed closely together Pseudocoelomate – Body cavity incompletely lined with mesoderm – fluid-filled cavity that contains their organs – Organs are free within the cavity and will move around easily when you manipulate them Coelomate – Cavity that contains organs – Lined with mesoderm

Type of Symmetry Asymmetrical – No particular symmetry Radial Symmetry – Circular organization – can be bisected in any plane to produce mirror images – Sessile Bilateral Symmetry – Definite right and left halves – only a cut down the midline will produce mirror images

Animal skeletons Can be: Hydrostatic Exoskeleton Endoskeleton

Animal skeletons Invertebrates – Lack an endoskeleton of bone or cartilage – All but one animal phylum are invertebrates Vertebrates – Have an endoskeleton of bone or cartilage

Reproduction Sexual reproduction egg of one individual is fertilized by the sperm of another Hermaphroditic animals possess both male and female sex organs Asexual reproduction single parent gives rise to an offspring that will be genetically identical to the parent Asexual reproduction of a body part!! Fertilization /Copulation Internal fertilization External fertilization Development of a fetus Internal External

Respiration Depends on environment Land Trachea Lungs Diffusion through body wall Water Gills Diffusion through body wall

Sponges

Phylum Porifera Saclike body with many pores Mainly aquatic animals Filter feeders Asexual and Sexual Reproduction – Hermaphroditic – Usually not self-fertilizing Spicules – For internal support (endoskeleton) – Asymmetrical – Incomplete digestive tract

Cnidarians

Cnidarians: True Tissues Phylum Cnidaria Tubular or bell-shaped with radial symmetry All aquatic, mostly marine

Cnidarians Cnidocytes – Stinging cells unique to cnidarians Two body types – Polyps and medusan Gastrovascular cavity – Sac-like body plan

Cnidarians Hydra – Freshwater – sac-like body plan with a single opening – Digestion begins in gastrovascular cavity, completed in cells – Can reproduce sexually and asexually (budding)

Flatworms

Phylum Platyhelminthes Bilateral symmetry Incomplete digestive tract Acoelomate

Flatworms Planarians – Found in lakes, ponds, and streams – Reproduce both asexually and sexually Regeneration (asexual) Hermaphroditic (sexual) – Reciprocal transfer – simultaneous transfer of the sperm to the genital orifice of the partner

Flatworms Parasitic Flatworms – Tapeworms Endoparasites Range in length from several millimeters to 20 meters Tough integument to protect from host’s enzymes Scolex

Roundworms

Roundworms: Phylum Nematoda – Tube within a tube body plan Mouth and anus – Hydrostatic skeleton – Nonsegmented – Some roundworms are free-living, others are parasitic

Roundworms: Pseudocoelomates Ascaris – Move with whip-like motion – Females are much longer than males and highly prolific – Eggs enter host in uncooked vegetables, soil, or feces

Coelomates The rest of the species that we will study are Coelomates – Bilateral symmetry – Organ level of organization – Tube-within-a-tube body plan

Molluscs

Second largest animal phylum Unique characteristics of molluscs – Three distinct parts Visceral mass Foot Mantle – Radula Grasping organ for feeding

Molluscs Gastropods – Nudibranchs, conchs, and snails Foot is flattened ventrally Aquatic gastropods have gills Terrestrial gastropods – Mantle has lung-like function

Molluscs Cephalopods – Squid, octopus, chambered nautilus Foot has evolved into tentacles Built for speed!! Extremely well-developed eyes – Complex behaviors Ink glands – Secrete “ink” as defense mechanism

Molluscs Bivalves – Clams, oysters, scallops Two-part shells (valves) Filter-feeders – Water enters through incurrent siphon

Annelids

Annelids: Segmented Worms Phylum Annelida – Segmentation – Hydrostatic skeleton – Tube-within-a-tube body plan

Annelids: Segmented Worms Oligochetes (Earthworms) – Locomotion Contraction of longitudinal and circular muscles Few setae per segment – Gas exchange is across the body wall

Annelids: Segmented Worms Oligochetes (Earthworms) – Reproduction Hermaphroditic Worms lie parallel in opposite directions – Clitellum produces mucus to keep sperm moist  After separation, produces a slime tube  Moves eggs and sperm together for fertilization  Slime tube then produces a cocoon

Annelids: Segmented Worms Leeches – Most live in freshwater – Most are ectoparasites - have suckers for feeding – Have same general body plan as other annelids Lack setae Each body ring has transverse grooves

Arthropods

Arthropods: Jointed Appendages Phylum Arthropoda – Over 1 million species have been described 30 million may exist (mostly insects) – Appendages are for: Walking, swimming, reproduction, eating, sensory reception – Exoskeleton of chitin (must molt to grow) – Well-developed nervous system Brain and ventral nerve cord Sense organs

Arthropods: Jointed Appendages Crustaceans – Barnacles, shrimps, lobsters, and crabs (marine) – Crayfish (freshwater) – Known for their hard shells – Cephalothorax – Usual anatomy is a pair of compound eyes and five pairs of appendages Front two pairs have sensory functions Other three pairs are used in feeding

Arthropods: Jointed Appendages Insects – Three body regions Head – Sensory antennae, eyes – Mouthparts are adapted to each insect’s way of life Thorax – Three pairs of legs and the wings Abdomen – Contains most internal organs

Comparison of Crayfish and Grasshopper Crayfish – Gills – Excrete liquid nitrogenous wastes (ammonia) – No reception of sound – Utilize uropods when swimming Grasshoppers – Spiracles and trachae – Grasshoppers excrete solid wastes (uric acid) – Tympanum for reception of sound – Have legs for hopping and wings for flying

Arachnids: 6 pairs of appendages Scorpions – Oldest terrestrial arthropods – Abdomen ends with a venomous stinger Ticks and Mites – Parasites Transmit diseases such as Rocky Mountain spotted fever or Lyme disease Spiders – Spiders have a narrow waist that separates cephalothorax from abdomen Chelicerae have fangs that deliver poison to prey Silk glands for web-spinning

Millipedes and Centipedes Millipedes: Eat decaying plant matter two pairs of short legs per body segment Centipedes: terrestrial carnivores with poison claws Have one pair of short legs per body segment

Echinoderms

Characteristics of Echinoderms – Marine animals – Endoskeleton made of calcium-rich plates – Spines stick out of their skin – Adults exhibit radial symmetry

Echinoderms Sea Stars – Found along shorelines on rocky surfaces – Five-rayed body with mouth on underside and anus on upper side – Structures project through skin Spines for protection Skin gills – Extensions of skin for gas exchange

Chordates

Must exhibit these characteristics: – Notochord – Dorsal tubular nerve cord – Pharyngeal pouches – Postanal tail

The Chordates……… Invertebrate chordates – Tunicates and lancelets Vertebrate chordates – Fishes – Amphibians – Reptiles – Birds – Mammals

Nonvertebrate Chordates Tunicates (sea squirts) – Squirt water when their siphons are disturbed Live in ocean and are filter-feeders Larva is bilaterally symmetrical and has four chordate characteristics Adults are sessile, thick-walled, sac-like organisms – The only chordate characteristics in the adults are pharynx and gill slits

Vertebrates Characteristics – Have four chordate characteristics at some point in life – Distinguishing features Strong, jointed endoskeleton Vertebral column composed of vertebrae Efficient respiration and excretion

Fishes Fishes: First Jaws, Then Lungs Adapted to life in water – Sperm and eggs released into water – Fertilization external – Zygote develops into swimming larval form Fish vs Fishes??? 2 chambered heart Ectothermic What are fish? – Jellyfish? – Starfish? – Crayfish? – Shellfish?

Fishes Three main groups/Classes of fishes – Jawless fishes – Cartilaginous fishes – Bony fishes

Amphibians Jointed appendages Class Amphibia – “two lives” – Tetrapods – Eyelids keep eyes moist – Have ears – Larynx for vocalization – Small lungs present in adults Gas exchange also occurs across moist skin – Three-chambered heart Ectothermic Large mouths and consume prey whole

Amphibians Have either internal or external fertilization Metamorphic life cycle – Aquatic larva (gills) - water – Terrestrial adult (lungs) - land

Class Amphibia Order: Gymnophiona Caecilians Order: Caudata Salamanders and Newts Order: Anura Frogs and toads

Reptiles Amniotic egg Class Reptilia – Body is covered with scales – Ectothermic – Three chambered heart**** – Eyelids

Reptiles Amniotes Tetrapods that have a terrestrially adapted egg Amniotic egg usually buried in substrate Contains membranes that protect the embryo In reptiles, internal fertilization

Class Reptilia – 4 Orders Order: Testudines – Turtles and tortoises Order: Crocodilia – Crocodilians Order: Rhynchocephalia – Tuataras

Class Reptilia – 4 Orders Order: Squamata – SO: Lacertilia Lizards 4 limbs and tail – SO: Serpentes Snakes Limbless – SO: Amphisbaenia Amphisbaenians Short tails Scales in rings Limbless Subterranean

Birds Class: Aves Amniote egg with a hard shell Internal fertilization, external incubation – Forelimbs are modified as wings – Bones are laced with air cavities – A beak has replaced jaws – Large sternum for attachment of flight muscles – Air sacs to increase the efficiency of breathing – Endothermic – Four-chambered heart – Cloaca

Mammals Class: Mammalia body hair and milk- producing mammary glands Adapted for active life on land Limbs that allow rapid movement Four-chambered heart Endothermic High level of care for the young Internal development (most)

Mammals Monotremes – Have a cloaca – Egg-laying mammals – Spiny anteater and duck-billed platypus Both found in Australia – Both males and females have modified sweat glands and secrete milk onto body surface

Mammals Marsupials – Begin development within female’s body born very immature development is completed within a pouch Attach to nipples of mammary glands within the pouch – Virginia opposum is the only marsupial species north of Mexico – Mainly found in Australia

Mammals Placental Mammals – Extraembryonic membranes are modified for internal development

How primates differ from most mammals : Most are adapted for living in trees Limbs are mobile, hands and feet have digits Opposable thumbs (sometimes big toes) Eyes in the front of the head Large, complex brain Generally give birth to one offspring at a time – Extended period of juvenile dependency