Ch. 26 Sponges and Cnidarians

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Ch. 26 Sponges and Cnidarians Powered By Docstoc
					    Animal Kingdom Notes
The Last Unit, The Second to last Lecture
        Animal Kingdom Outline

   Introduction to the Animal Kingdom
     What is an Animal?
     What Animals do to survive
     Trends in Animal Evolution
        Animal Kingdom Outline

   Invertebrates
     Sponges and Cnidarians
     Worms and Mollusks
     Arthropods and Echinoderms

   Chordates
     Fishes and Amphibians
     Reptiles and Birds
     Mammals
          What is an Animal?
   Multicellular, eukaryotic heterotrophs that lack cell
    walls. Bodies of most contain tissue:
       Epithelial – cover body surfaces, i.e. lung surface
       Muscle – able to contract for movement, i.e. Biceps
       Connective – support body and connects its parts, i.e.
        bone and blood
       Nervous – carry information throughout the body, i.e.
        nerve cells
   Grouped as: invertebrates (over 95% of animals)
    do not have a backbone, or vertebrates (5%) do
    have a backbone.
       What animals do to survive

1.   Feeding – herbivores, carnivores,
     omnivores, detritivores, filter feeders,
2.   Respiration – taking in oxygen and
     exchanging it for CO2, by diffusion or
     complex systems.
3.   Circulation – moving oxygen, nutrients,
     and waste throughout body, by diffusion or
     complex systems.
        What animals do to survive
4.   Excretion – the elimination of metabolic wastes
     like ammonia, range from cells that pump out
     water to complex systems.
5.   Response – reacting to stimuli in the
     environment, ranges from simple
     ganglia/receptor cells to complex systems
6.   Movement – some animals are sessile but most
     do move, most use muscle cells and skeleton to
7.   Reproduction – sexually by the exchange of
     gametes, or asexually by budding, fragmentation,
     regeneration, etc.
          Early Development
 All sexually reproducing animals begin life as
  a zygote (fertilized egg)
 Then, the zygote goes through several
  divisions to become a blastula (a hollow ball
  of cells).
 The blastula continues to divide and fold
  inward forming a blastopore (an elongated
  structure with a tube inside).
       The tube becomes the digestive tract and forms
        one of two ways:
       Early Development

1.   Protostome – an animal whose mouth is
     formed from the blastopore (most
2.   Deuterostome – an animal whose anus is
     formed from the blastopore (echinoderms
     and all vertebrates)
        Early Development

   The cells of developing embryos differentiate
    into three germ layers, which give rise to
    developing body parts:
     Endoderm – inner layer, lining of the digestive
      tract and respiratory system.
     Mesoderm – middle layer, muscles, circulatory,
      reproductive, excretory systems
     Ectoderm – outer later, sense organs, nerves,
      and outer skin layer.
         Body Symmetry

    Except for sponges, every animal exhibits
    1.   Radial – body parts that repeat around the
         center of the body
    2.   Bilateral – body divides into two equal right
         and left sides, have an anterior, posterior,
         dorsal, and ventral side, allows for
         segmentation and external body parts that
         repeat on either side.
Body Symmetry
                          Bilateral Symmetry
Radial Symmetry
                                 Posterior end
                                                 Dorsal side

                  Anterior end

                                                  Ventral side

                                                  Plane of

    Planes of

   Animals with bilateral symmetry usually have
    sense organs and nerve cells gathered at
    the anterior end of the body, allows for
    quicker response times, usually referred to
    as the head.
      What is a Sponge?

 The most ancient, simplest, and unusual
  animals living on the Earth for at least 540
  million years.
 Phylum Porifera – “pore bearer”, bodies
  filled with tiny pores, sessile, eukaryotic,
  multicellular, heterotrophs, no cell walls.
          Form and Function in
 No mouth or gut, no tissues or organ
  systems, few specialized cells that carry out
  like processes.
 Body Plan
       Asymmetrical
   Feeding
       Filter feeders
   Respiration, Circulation, and Excretion
       Diffusion and Osmosis
        Anatomy of the Sponge

                 Water flow
Central cavity                Choanocyte
  Pores                       Spicule
                              Pore cell

                              Epidermal cell

          Form and Function in
   Response
       No Nervous system, some produce toxin to
        avoid predation.
   Reproduction
     Sexually by forming egg or sperm by meiosis.
     Asexually by Budding, part of the adult sponge
      breaks off and grows into a new sponge
           What is a Cnidarian?
   Phylum Cnidaria includes hydras, jellyfishes, sea
    anemones, and coral that live in waters all over the
   Soft-bodied, carnivorous animals that have stinging
    tentacles surrounding their mouths.
   Their name comes from their cnidocytes, stinging
    cells, located on the tentacles, used for defense or
    capturing prey.
       Inside the cnidocyte is a nematocyst, poison-filled
        stinging dart. Can paralyze or kill prey or predators.
      Body Plan

 Radial symmetry with a central mouth
  surrounded by tentacles.
 Most have an alternating life consisting of a
  polyp and medusa.

         Tentacles                          Mesoglea
                                            Gastrovascular cavity
        Mouth/anus                          Mouth/anus
       Gastrovascular                       Tentacles


   Prey is pulled through the only opening
    (mouth), into the gastrovascular cavity where
    digestion begins extracellularly. The partially
    digested food is then absorbed by the
    gastroderm to complete digestion
    intracellularly. Wastes are released back out
    the mouth.
           Form and Function in
   Respiration
       Oxygen, nutrients, and wastes are moved into and out of
        body wall by diffusion
   Response
       A nerve net.
       Statocysts = direction of gravity.
       Ocelli = eyespots
   Movement
       Most medusa’s move through jet propulsion
   Reproduction
       Asexually by budding
       Sexually by releasing egg and sperm into water
          Class of Cnidarians
   All live underwater and mostly in oceans.
   Jellyfishes
       Class Scyphozoa – “Cup animals”, medusa as adults,
        polyps as larvae, no elaborate colonies ever form,
        reproduce sexually.
       Class Cubozoa – “Box Jellies”, deadliest Jelly Fish
   Hydras and Their Relatives
       Class Hydrozoa – polyps, most grow in colonies, i.e.
        portuguese man-of-war.
       Hydras are freshwater organisms that lack a medusa
        stage. They live as solitary polyps and reproduce
        sexually or asexually
          Groups of Cnidarians

   Sea Anemones and Corals
       Class Anthozoa – “flower animals”, only polyp
          Sea Anemones are solitary.
          Coral polyps are colonial and secrete an underlying
           skeleton of CaCO3 or limestone.
               Coral reefs are made up of many coral colonies growing
                near one another.
               Reproduce sexually or asexually by budding.
        Worms and Mollusks

   Worms
     Flatworms
     Roundworms
     Annelids

   Mollusks
     Gastropods
     Bivalves
     Cephalopods

 Scientists classify worms according to their
  body shape.
 Three Body Plans:
     Acoelomates – An organism without a coelom,
      body cavity
     Pseudocoelomates – An organism with a “fake”
      body cavity.
     Coelomates – An organism that contain a true
      body cavity

   Flatworms: Phylum Platyhelminthes
       Soft, flattened worms that have tissues and
        internal organs, acoelomates.
          Flame Cells = First “Kidney”-like structure
          Ganglia = First “Brain”-like structure

       The simplest animals to have three germ layers,
        bilateral symmetry, and cephalization
                        Eyespot                    Ganglia    Freshwater flatworms have
                           Head                               simple ganglia and nerve
                                                    Nerve     cords that run the length of
                 Gastrovascular                     cords     the body. The excretory
                         cavity                               system consists of a network
                                                              of tubules connected to flame
Flatworms use a pharynx to suck
                                                 Excretory    cells that remove excess
food into the gastrovascular
                                                   system     water and cell wastes.
cavity. Digested food diffuses
from the cavity into other cells of
the body. Eyespots in some                                    Ovary
species detect light.                                         Testes

                Mouth                          Pharynx
                                                              Most flatworms are
                                                              hermaphrodites, having male
                                                              reproductive organs (testes)
                                                              and female reproductive
                                                              organs (ovaries) in the same

                                  Flame cell
           Groups of Flatworms
   Turbellarians
       Free-living flatworms, mostly in marine or fresh water.
   Flukes
       Parasitic flatworms that infect internal organs of host
   Tapeworms
       Long, Flat, Parasitic worms that are adapted to live
        inside the intestines of their hosts.
   Roundworms: Phylum Nematoda
       Slender, unsegmented worms with tapering ends.
       Have a digestive tract with two openings, but no true
        body cavity, pseudocoelomate.
       Most are free-living, but some are parasitic.
   Parasitic roundworms include:
       Trichinosis-Causing Worms
       Filarial worms
       Ascarid Worms
       Hookworms
Parasitic roundworms
   Segmented Worms: Phylum Annelida
       Worms with segmented Bodies
       They have a true coelom that is lined with tissue.
       First animals with a CLOSED circulatory system.
            Blood contained in Vessels
       Nephridia = primitive Kidney
       Well-developed nervous system and brain
   Three main Classes
       Oligochaetes
       Leeches
       Polychaetes
         Ecology of Worms

    Earthworms and many other annelids
     continually burrow through the soil. This
     does several things:
    1.   Aerates the soil
    2.   Tunnels provide paths for plant roots
    3.   Bacteria can grow in their tunnels
    4.   Help plant matter decompose
    5.   Mix Minerals throughout the soil
    Mollusks: Phylum Mollusca
        Mollusks are soft-bodied animals that usually have an
         internal or external shell
        Examples: snails, slugs, clams, squids, and octopi
        Most have an OPEN Circulatory System
    Body Plan
    1.   Foot
    2.   Mantle
    3.   Shell
    4.   Visceral Mass
           Groups of Mollusks
   Gastropods
       Shell-less or single shelled mollusks that move be using
        a muscular foot located on the ventral side
   Bivalves
       Two shells that are held together by one or two powerful
   Cephalopods
       Soft-bodied mollusks in which the head is attached to a
        single foot. The foot is divided into tentacles or arms.
   Characteristics that all Arthropods share:
       Tough Exoskeleton
            Made of Chitin
       Jointed Appendages
       Segmented Body
   They are classified by the number and structure of
    their body segments and appendages.
       Crustaceans
       Arachnids
       Insects

   Characteristics contributing to their
    evolutionary success:
     Evolution of Flight
     Responses to stimuli
          Compound   Eye
       Life Cycle in which young differ from adults
   Three body parts
     Head, thorax, and abdomen
     Three pairs of legs attached to thorax
   Echinoderms: Phylum Echinodermata
       Characteristics
          Endoskeleton
          Water Vascular System
          Tube Feet
          Five part radial symmetry

   Groups of Echinoderms
     Sea Urchins and Sand Dollars
     Sea Stars
     Sea Cucumbers

    Four Anatomical features characterize
     Phylum Chordata
    1.   Notochord: Flexible rod between the digestive
         tube and the nerve cord
    2.   Dorsal, Hollow nerve cord
         1.   Develops into Brain and Spinal Cord
    3.   Pharyngeal Slits
    4.   Muscular, Postanal Tail
    What happened to our four characteristics?
       Characteristics of Vertebrates

1.   Bilateral Symmetry
2.   Complete Digestion
3.   A Vertebral Column
4.   Closed Circulatory System
5.   Aquatic or terrestrial
           Overview of Chordate
   Urochordata (Tunicates)
   Cephalochordata (Lancelets)
   Agnatha (jawless Vertebrates)
       Lampreys
   Chondrichthyes (Cartilage fishes)
       Sharks
   Osteichythyes (bony fishes)
       Snapper, Tuna, the fish we catch and eat
   Amphibia (Frogs and Salamanders)
   Reptilia (reptiles)
   Aves (Birds)
   Mammalia (Mammals)
          Common Group Names

 Vertebrates: Agnatha through Mammalia
 Tetrapods: 2 pairs of limbs
       Amphibia, Reptilia, Aves, Mammalia
   Amniotes: Have Shelled, water retaining
    eggs or a uterus
       Reptilia, Aves and Mammalia
          Differences in Chordates

   Reproduction
       Oviparous – Eggs hatch outside of organism
          Ex:   Reptiles and Aves, some fish like Salmon.
     Ovoviviparous – Eggs stay inside mothers body
      and are nourished by the egg yolk and not by
      the mother.
     Viviparious – Live birth from mother
          Mammals
          Differences in Chordates

   Body Temperature Regulation
       Ectotherm
         Body   Temperature is controlled from outside of the
         “Cold Blooded”

       Endotherm
         Body Temperature is controlled from the inside
          through the metabolism of food
         “Warm Blooded”
          Heart Structure
   Fish, Amphibians, Reptiles, Aves, and Mammals
    differ in the number of chambers inside the heart.
   Fish = 2-chambered heart – Just a pump
   Amphibians = 3-chambered Heart
       Mixes Deoxygenated blood with Oxygenated Blood
   Reptiles = 3 ½-chambered Heart
       Has a hole in the wall that separates deoxygenated
        blood from oxygenated blood
   Aves/Mammals = 4-chambered heart
       Completely Separates deoxygenated blood from
        oxygenated blood.
Heart Chambers
Heart Chambers
          Differences in Mammals

   Births
       Monotremes
          Mammals     that lay eggs
       Marsupials
          Embryos    Grow outside of the body in a pouch
       Plancentals
          Embryos    grow in a placenta inside the mother.
              Placenta - organ in placental mammals through which
               nutrients, oxygen, carbon dioxide, and wastes are
               exchanged between embryo and mother

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