Invertebrates

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Invertebrates
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Phylum Porifera

• Ex Sponges-
• sessile as adults, motile as larvae (no true
  tissues)
• Body Plan asymmetrical, contains large central
  cavity through which water continually flows
• movement of water acts as its respiratory,
  circulatory and excretory system
• spicules form simple skeleton in hard sponges,
  spongin forms skeleton in soft sponges

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Phylum Porifera

• Feeding filter feeders with intracellular
  digestion, (each cell does its own digestion)
• choanocytes (collar cells) line the walls of the
  sponge and have flagella which trap food and act
  as digestive system
• the digested food is passed on to the
  archaeocytes which then transports it throughout
  the sponge acts as simple circulatory system

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Phylum Porifera

• Response no nervous system or defense system
  (taste bad)
• Reproduction both asexual and sexual
• Asexual
• a. budding - part breaks off of parent sponge,
  settles to ocean bottom and grows into new sponge
• b. gemmules group of archaeocytes surrounded by
  spicules these can survive unfavorable
  environmental conditions
• Sexual sponges are hermaphrodites and contain
  both sperm and eggs in single sponge
• sperm released through osculum is carried into
  other sponges where it joins and fertilizes an
  egg produces larvae which is free swimming,
  lands on ocean floor and then grows into adult
  sponge

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Phylum Porifera

• Ecology form habitats for many other marine
  animals also forms symbiotic relationships with
  photosynthetic organisms (algae makes some appear
  green)

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Phylum Cnidaria

• ex hydras, corals, sea anemones, jellyfish
• soft-bodies, carnivorous animals with stinging
  tentacles surrounding mouths
• nematocysts are poison-filled structures that
  contain a tightly coiled dart and are triggered
  when an animal brushes against it
• poisonous enough to paralyze or kill prey
  (including humans)

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Phylum Cnidaria

• Body Plan radial symmetry
• Life cycle includes two different looking stages
• a. polyp cylindrical body with mouth pointing
  upward sessile as adults
• b. medusa motile, bell-shaped with mouth on
  bottom
• body has 2 tissue layers

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Phylum Cnidaria

• Feeding - incomplete digestive system with one
  opening serving as both its mouth and anus
• gastrovascular cavity allows for extracellular
  digestion which occurs outside the cells
  themselves
• GVC is lined by gastroderm tissue
• Respiration/Circulation/Excretory System
• occurs by diffusion through body walls

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Phylum Cnidaria

• Response nerve net, a loosely organized network
  of nerve cells, allows cnidarians to detect
  stimuli and trigger the nematocysts
• Movement some have hydrostatic skeleton, which
  contain a layer of muscles that along with water,
  allow cnidarians to move
• medusas move by jet propulsion
• Reproduction both sexual and asexual
• Sexual external fertilization in the water
  Asexual budding

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Phylum Platyhelminthes

• Ex Flatworms planarians, tapeworms, flukes
• simplest animals have 3 embryonic germ layers
  (ectoderm, mesoderm, endoderm) -gt acoelomates (no
  body cavity)
• soft, flattened, unsegmented worms
• simplest animals with bilateral symmetry and
  cephalization

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Phylum Platyhelminthes

• Form/Function
• flatworms that are free-living have organ
  systems for feeding, excretion, response and
  reproduction
• parasitic flatworms (tapeworms) contain modified
  internal organs and structures or none at all
  live off host
• flattened shape allows more cells to be at
  surface and allows for more efficient diffusion
  of nutrients and wastes

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Phylum Platyhelminthes

• Feeding - carnivorous, scavengers, parasitic
• have GVC with single opening (incomplete
  digestive system)
• mouth (pharynx), located on ventral side pumps
  food into the GVC, where it is digested and
  diffused to other parts of the body

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Phylum Platyhelminthes

• Respiration/ Circulation and Excretion
• uses diffusion to move oxygen and nutrients to
  internal tissues
• have no gills, no heart, blood vessels or blood
• flame cells used for excretory system

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Phylum Platyhelminthes

• Response
• ganglia group of nerve cells in anterior end
  which attaches to ladder-type nervous system
• eyespot in anterior end detects light/dark
• Movement use cilia on epidermal cells and
  muscles
• Reproduction both sexual and asexual
• most are hermaphrodites and use sexual
  reproduction
• asexual involves binary fission and regeneration

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Phylum Nematoda

• Roundworms
• slender, unsegmented worms with tapered ends
• pseudocoelomates (false body cavity) partially
  lined with mesoderm
• bilateral symmetry

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Phylum Nematoda

• Feeding complete digestive system with two
  openings (mouth and anus) - free-living,
  parasitic, scavengers
• Respiration/Circulation/Excretion uses
  diffusion, no internal transport system
• Response several ganglia in simple nervous
  system
• Movement circular muscles, along with
  hydrostatic skeleton, produces jerking motion
• Reproduction sexual with separate sexes

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Phylum Nematoda

• Parasitic Roundworms and Human Disease
• Trichinosis-causing worms (Trichinella) found
  in pork larvae of worms form cysts and bury
  into hosts muscle (pigs) when eaten, they
  begin life cycle in new host
• Filarial worms causes elephantiasis live in
  lymph and blood vessels, blocking their passages
  which causes extreme swelling
• Ascaris get by not washing veggies and other
  foods live in hosts intestines where they
  absorb hosts food and can cause malnutrition
• Hookworms get by walking barefoot worms
  burrow through soles of feet and enter the
  bloodstream there, they travel to intestine
  where they suck hosts blood, causing weakness
  and poor growth

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Phylum Annelida

• ex earthworms, leeches, marine worms
• body divided into segments, separated by septa
  (internal walls)
• setae (bristles) on each segment help them move
  through soil
• coelomates with a true body cavity completely
  lined with mesoderm
• bilateral symmetry with cephalization

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Phylum Annelida

• Feeding- filter feeders, carnivores, detritivores
• complete digestive system (two openings)
• Circulatory system have a closed circulatory
  system (blood is always contained in blood
  vessels)
• have two major vessels
• dorsal blood vessel moves blood towards anterior
  end
• ventral blood vessel moves blood towards
  posterior end
• at anterior end, the dorsal blood vessel forms 5
  arches which act as simple hearts by contracting
  to pump blood throughout body

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Phylum Annelida

• Respiration terrestrial annelids breathe
  through moist skin and produce mucus to keep skin
  moist (explains why earthworms are found in moist
  soil)
• aquatic annelids use gills
• Excretion nephridia removes nitrogenous wastes
• solid wastes removed through anus

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Phylum Annelida

• Response well-developed nervous system contains
  ganglia and several nerve cords
• may have two or more pairs of eyes, sensory
  tentacles and ventral nerve cord
• Movement have circular and longitudinal muscles
  and move by alternating the contractions of these
  

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Phylum Annelida

• Reproduction- earthworms and leeches are
  hermaphrodites
• each earthworm exchanges sperm cells which are
  then used to fertilize egg cells
• the clitellum secretes a mucus ring in which both
  egg and sperm are released
• the ring slips off and forms a cocoon, which
  worms hatching later

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Phylum Mollusca

• ex snails, slugs, clams, squid
• soft-bodied animals, usually with an internal or
  external shell
• Body Plan most have 4 parts
• Foot many forms, spadelike in clams, tentacles
  in squid/octopi
• Mantle thin layer of tissue that covers most of
  mollusks body
• Shell reduced/lost in some (slugs)
• Visceral mass consists of internal organs

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Phylum Mollusca

• Feeding
• herbivores, carnivores, filter feeders,
  detritivores, parasites complete digestive
  system
• in some, radula is used to scrape surface
  (snails)
• carnivorous (octopi) use radula to drill holes in
  prey
• clams/oysters are filter feeders using siphons to
  pull water in/out of body

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Phylum Mollusca

• Respiration
• most use gills (aquatic) and diffusion
• terrestrial snails/slugs use mantle cavity
  diffusion
• Circulation
• slow-moving mollusks have an open circulatory
  system in which the blood leaves vessels and
  bathes the organs in blood
• collected in sinuses and goes to the gills where
  gas exchange takes place
• blood is then returned to the heart and process
  begins over
• carnivorous mollusks (squid) have closed
  circulatory sytem which is more efficient in gas
  exchange

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Phylum Mollusca

• Excretion
• nephridia used to remove nitrogenous wastes
• Response
• ranges from simple system in filter feeders to
  very advance in carnivores
• octopus are active and considered most
  intelligent invertebrate because they can learn
  and be trained

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Phylum Mollusca

• Movement
• snails/slug use muscular foot
• octopus/chambered nautilus use jet propulsion
• Reproduction
• sexual, both external and internal fertilization
• most snails are hermaphrodites

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Phylum Arthropoda

• most successful phylum with biggest diversity and
  largest of individuals
• All arthropods contain
• 1. segmented body made of either two or three
  parts
• 2. exoskeleton (made of chitin) protects and
  supports the body, provides attachment site for
  muscles and helps prevent water loss
• 3. jointed appendages structures such as legs
  and antennae

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Phylum Arthropoda

• Feeding - includes herbivores (grasshoppers),
  carnivores (spiders), omnivores, filter feeders,
  detritivores and parasites
• Circulation - open circulatory system with
  well-developed hearts
• Excretion
• a. Malpighian tubes in terrestrial
• b. green glands in aquatic

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Phylum Arthropoda

• Respiration
• terrestrial arthropods use either
• a. tracheal tubes extend through body air
  enters and leaves tracheal tubes through
  spiracles, which are holes along the side of the
  body (insects)
• b. book lungs (arachnids) organs contain
  stacked layers of respiratory tissue which look
  like pages of a book
• c. gills (crustaceans) or book gills (horseshoe
  crabs) used in aquatic

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Phylum Arthropoda

• Response all arthropods have simple brain
• most have well-developed nervous system
• lack overall intelligence but have highly
  developed sense organs
• most have sophisticated sense organs, including
  compound and simple eyes and taste receptors on
  antennae
• Movement
• well-developed groups of muscles that are
  controlled by nervous system
• Reproduction - sexual, with both internal and
  external fertilization

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Phylum Arthropoda

• Growth/Development
• as arthropods grow, they outgrow their
  exoskeleton, which must be molted, making the
  animal vulnerable during the time it takes for
  new exoskeleton to harden

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Phylum Echinodermata

• ex sea stars, sea cucumbers, sand dollars
• spiny skins, endoskeleton, water vascular system
• radial symmetry with a 2-sided body
• a. side w/ mouth ? oral surface
• b. opposite side ? aboral surface

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Phylum Echinodermata

• Feeding
• use different methods some herbivores (some sea
  urchins), detritivores (sea cucumbers),
  carnivores (sea stars)
• sea stars extrude stomachs through its mouth,
  pours out digestive enzymes and digests mollusk
  in its own shell when finished, it pulls its
  stomach back in

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Phylum Echinodermata

• Excretion
• uses diffusion to remove nitrogenous wastes
  through skin gills and tissues of tube feet
• Response
• no highly developed nervous system
• nerve ring surrounds mouth with radial nerves
  that connect ring with body sections
• scattered sensory cells detect light, gravity,
  and chemicals released by prey

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Phylum Echinodermata

• Circulation and Respiration
• Water vascular system acts as respiratory and
  circulatory system and also helps in movement and
  getting food

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Phylum Echinodermata

• Movement most use tube feet, sand dollars and
  sea urchins use moveable spines
• Tube feet act as suction cups to walk with and
  open shells of mollusks (prey)
• Reproduction
• sexual, external fertilization
• starfish can regenerate if portion of central
  disk is present