Kingdom Animalia Invertebrates

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Kingdom Animalia (Invertebrates)
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Characteristics of Animals

• Multicellular
• Eukaryotic
• Heterotrophic consumers
• Most are motile, but some are sessile
• Most consist of cells that are organized into
  tissues and organs
• Most reproduce sexually

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Habitats of Animals

• Terrestriallive on land
• Aquaticlive in water
• Freshwaterlive in water that is not salty (ex.
  ponds, lakes, streams, rivers)
• Marinelive in salt water (ex. oceans)

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Classification of Animals

• Invertebratesanimals without a backbone (95 of
  animals)
• Vertebratesanimals with a backbone (5 of
  animals)

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Types of Body Symmetry

• Asymmetryhave no symmetry (ex. sponges)
• Radial Symmetryhas parts arranged around a
  central axis any plane passing through the
  central axis divides the animal into halves that
  are mirror-images of one another (ex. jellyfish,
  starfish)
• Bilateral Symmetrythe right and left half of the
  animal are mirror-images of each other animals
  with this type of symmetry generally have
  cephalization, a concentration of nervous tissue
  in the head region (ex. worms, insects, humans)

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Anatomical Terminology

• Dorsalthe back surface of an animal
• Ventralthe underside of an animal
• Anteriorthe front end of an animal
• Posteriorthe rear end of an animal
• Lateralthe sides of an animal
• Medialalong the midline of an animal

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Primary Animal Phyla

• Poriferasponges
• Cnidariajellyfish, coral, Portuguese Man-of-War,
  hydra
• Platyhelminthesflatworms (tapeworms, flukes,
  planarians)
• Nematodaroundworms (pinworms, hookworms)
• Annelidasegmented worms (earthworms, leeches)

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Primary Animal Phyla (continued)

• Molluscasnails, slugs, octopus, squids, clams,
  oysters
• Arthropodainsects, spiders, scorpions, crayfish,
  crabs
• Echinodermatastarfish
• Chordatafish, frogs, snakes, turtles, lizards,
  birds, dogs, cats, horses, humans

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Phylum Porifera

• pore bearers, the sponges
• Have no definite shape or symmetry
• Have no tissue organization
• Most are marine, but some are freshwater
• Adult sponges are sessile larvae are
  free-swimming

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Phylum Porifera (continued)

• The body of a sponge is shaped like a sac the
  inside is a hollow cavity
• Sponges have a large opening at the top of the
  cavity called an osculum (no mouth)
• The body of a sponge has numerous tiny pores,
  through which water moves into the animal the
  sponge gets its food and oxygen from this water

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Phylum Porifera (continued)

• Sponges are filter feeders as water moves into
  the sponge through the pores, it is filtered of
  small particles of food
• Collar cells are cells that line the inner body
  cavity they have flagella which beat to draw
  water through the sponge and out the osculum,
  filtering the water in the process
• Spicules are needle-like structures that support
  the soft material of a sponge

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Phylum Porifera (continued)

• Sponges can reproduce either asexually or
  sexually
• During asexual reproduction, a small growth, or
  bud, can break off the main part of the sponge,
  attach to a substrate, and eventually grow into a
  separate new sponge
• During sexual reproduction, specialized cells can
  develop into either sperm or eggs the sperm swim
  out of the osculum and into another sponge there
  they fertilize eggs the larvae swim out of the
  osculum to become new sponges

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Phylum Porifera (continued)

• Sponges are hermaphroditic, which means that they
  produce both sperm and eggs
• Most have the ability to regenerate when cells
  of a sponge are separated from one another (as
  when they are injured), they can reorganize and
  form a new sponge

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Phylum Cnidaria

• Animals with stinging cells
• Jellyfish, Hydra, Obelia, coral, sea anemone,
  Portuguese Man-of-War
• Most are marine
• Have radial symmetry
• Have some tissue organization

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Phylum Cnidaria (continued)

• There are two main body forms found in
  cnidarians
• Polypcylindrical, usually sessile animals which
  have their mouths directed upwards and tentacles
  surrounding it
• Medusagenerally free-floating, umbrella-shaped
  animals which have their mouths directed
  downwards and tentacles hanging down around it

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Phylum Cnidaria (continued)

• Some cnidarians exist only as polyps some exist
  only as medusae others alternate between the two
  forms
• Some cnidarians exist singly some exist as
  colonies of animals
• Cnidarians can reproduce asexually (by budding)
  or sexually (by production of gametes)

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Phylum Cnidaria (continued)

• Cnidarians have stinging cells which are used in
  capturing prey when stimulated, the cells
  poison/paralyze the prey so it can be eaten
• The mouth of the animal leads into a cavity where
  digestion occurs
• Wastes are expelled out the mouth

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Phylum Platyhelminthes

• Flatworms (ex. planarians, flukes, and tapeworms)
• Have flattened bodies, bilateral symmetry, and
  cephalization
• Have distinct tissue layers
• Simplest animals with organs

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Planarians

• Free-living flatworms
• Freshwater (found in ponds, lakes, and streams)
• Scavengers
• Hermaphroditic
• Breathe through skin
• Regenerate well

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Planarians (continued)

• Mouthonly body opening located halfway down the
  body on the ventral surface can project its
  pharynx (throat) out the mouth to suck up food
• Intestinesdigest food
• Eyespotssensory structures used for detecting
  light planarians prefer darkness

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Flukes

• Parasitic flatworms (internal parasites) blood
  flukes and liver flukes can infect humans
• Oral suckers enable the worm to attach to the
  intestines of the host
• Hermaphroditic body primarily consists of
  reproductive organs

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Life Cycle of a Fluke

• Eggs are released from an infected individual
  with wastes in some areas of the world, human
  wastes are used as fertilizer for crops
• Eggs hatch into larvae in swampy, marshy land
  areas (mainly in Asia and the tropics)
• Sometimes snails serve as intermediate hosts
• Larvae may enter humans through the skin (of the
  feet usually)
• Larvae then pass through the bloodstream to the
  intestines, where they attach, feed, and
  reproduce

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Tapeworms

• Parasitic flatworms (internal parasites) beef
  tapeworms, fish tapeworms, and pork tapeworms can
  infect humans
• The tapeworms head has hooks and suckers which
  enable the worm to attach to the hosts intestine
• The body consists of a long chain of segments

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Tapeworms (continued)

• Hermaphroditic each segment contains
  reproductive organs
• Segments that are farthest from the head contain
  mature eggs these are shed daily and released
  from the body of an infected individual with the
  feces

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Life Cycle of a Tapeworm

• If a human eats poorly cooked beef, pork, or fish
  that contains larvae, infection can occur
• The cow, pig, or fish (intermediate hosts) can be
  infected by eating food which contains the
  tapeworm eggs
• Once inside the animal, the eggs become embryos,
  and then larvae the larvae encyst in muscle,
  which is the part eaten by humans
• When a human eats the infected meat, digestive
  juices break down the cysts and release the larvae

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Life Cycle of a Tapeworm (continued)

• The larvae attach to the intestines, where they
  feed, grow, and reproduce, when mature
• Tapeworms may grow up to 50 feet long and may
  live within a host for up to 10 years
• Symptoms of infection include weight loss,
  increased appetite, and occasionally pain and
  discomfort

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Phylum Nematoda

• Roundworms (ex. hookworms, pinworms, heartworms)
• Found almost everywherein soil, freshwater, and
  saltwater many are parasites
• Have a tube-like body and bilateral symmetry
• Distinct tissue layers and definite organs
• Usually separate sexes males are generally
  smaller in size than females

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Phylum Nematoda (continued)

• Complete digestive tract with a mouth at one end
  and an anus at the other
• Body is covered by a tough cuticle, which is a
  thickening of the epidermis that protects the
  worm (from drying out) the cuticle is shed, or
  molted, as the worm grows
• Beneath the epidermis is a layer of muscles that
  allows the worm to move by thrashing back and
  forth

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Hookworms

• Internal parasites live in the human intestine,
  where they feed, mature, and lay eggs
• The eggs pass out of the body with the feces
• If human wastes are used as fertilizer, the
  larvae develop in the soil
• They may enter a human through the skin (usually
  by boring through the skin of the feet as an
  individual walks on soil contaminated with
  larvae)
• The larvae migrate through the body to the
  intestine

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Pinworms

• The most common parasitic worms found in children
• May enter a human host if the individual ingests
  eggs by eating with dirty hands
• Adult worms are about ½ inch long
• They live in the large intestine

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Pinworms (continued)

• Female worms migrate to the hosts anus (usually
  at night) to deposit eggs
• This causes itching, irritation, and scratching,
  which spreads the eggs
• The eggs can even be spread in the air to other
  people
• Some pinworm infections are mild some cause much
  intestinal discomfort

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Phylum Annelida

• Segmented worms (ex. earthworms, leeches,
  sandworms) have many body segments
• Found in freshwater, marine, or terrestrial
  habitats
• Have bilateral symmetry

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Leeches

• Live in freshwater, but are also external
  parasites
• May attach to the skin of a host with suckers at
  each end of the body
• Suck blood, which is stored in pouches within
  their bodies
• Secrete an anticoagulant which keeps blood from
  clotting leeches are occasionally used in
  medicine

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Earthworms

• Burrow in the soil using paired bristle-like
  structures these structures are found on the
  ventral surface of each body segment
• Earthworms are important ecologically because
  they aerate the soil as they burrow

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Earthworms (continued)

• Complete digestive tract with a mouth at one end
  and an anus at the other
• Body is covered by a cuticle, which is secreted
  by the epidermis and helps to prevent the worm
  from drying out the epidermis also secretes
  mucus to further prevent drying out

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Earthworms (continued)

• Body wall consists of an outer layer of circular
  muscles and an inner layer of longitudinal
  muscles
• Respiration occurs through the skin
• Kidney-like structures that excrete liquid wastes
  located in each body segment

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Earthworms (continued)

• Digestive system is quite advanced consists of
  the following structures (in order from anterior
  to posterior)
• Mouthfood (mixed with soil) enters here
• Pharynxthroat a passageway
• Esophagusa passageway
• Cropstores food
• Gizzardgrinds food
• Intestinedigests food a passageway
• Anuseliminates wastes

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Earthworms (continued)

• Circulatory system is also quite advanced
  consists of the following structures
• 2 main blood vessels, one dorsal and one ventral
• 5 pairs of arched blood vessels that connect the
  other two vessels these vessels pump blood, so
  they make up the heart

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Earthworms (continued)

• Nervous system consists of
• Ventral nerve cord
• Paired masses of tissue called ganglia this is
  the brain

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Earthworms (continued)

• Hermaphroditic
• Reproductive system consists of
• Clitelluma thickened band of the epidermis that
  secretes a mucus substance, which is used to hold
  two worms together during sexual reproduction
• Seminal vesiclesproduce sperm
• Seminal receptaclesreceive and store sperm

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Phylum Mollusca

• Soft-bodied animals
• Includes snails, slugs, clams, scallops, oysters,
  octopuses, squids
• Many are marine, but some are freshwater, and
  some are terrestrial
• The body of most mollusks is covered by a shell

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Structure of Mollusks

• A muscular foot is used for movement in the
  octopus and squid, the foot is divided into
  tentacles, which are also used for food-getting
• The visceral mass contains most of the internal
  organs
• The mantle is a heavy fold of tissue which covers
  the visceral mass it contains glands that
  secrete the shell
• Gills are used for respiration in aquatic mollusks

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Structure of Mollusks (cont.)

• Mollusks have a digestive system consisting of a
  mouth, esophagus, stomach, intestine, and anus
• Many have an open circulatory system, which
  consists of a heart, blood vessels, and blood in
  an open system, though, the blood bathes the body
  tissues directly by pooling in a blood-filled
  cavity

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Structure of Mollusks (cont.)

• Sexes are usually separate, and fertilization
  generally takes place in the surrounding water
  most marine mollusks pass through one or more
  larval stages

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Special Mollusk Features

• Bivalve mollusks are filter feeders they get
  food particles from the water they draw into
  their bodies
• If a piece of foreign matter lodges between the
  bivalves shell and mantle, a pearl can form
• The mantle secretes the shell the interior of
  the shell is made of a substance called mother of
  pearl this substance surrounds the foreign
  particle and forms a pearl

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Special Mollusk Features (cont.)

• Cephalopods (octopus and squid) are active,
  predatory animals that move by jet propulsion
  they take in water, and then force it out to push
  themselves through the water
• The octopus has 8 tentacles the squid has 10
• An octopus has no shell the squids shell is a
  hard, internal structure called a pen

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Special Mollusk Features (cont.)

• Cephalopods are active at night and in the dark
  depths of the ocean they have large,
  well-developed eyes that can actually see images
  (much as human eyes)
• Many cephalopods can change colors to fool
  predators some have ink sacs that release a dark
  liquid that blinds predators

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Phylum Arthropoda

• The most successful group of animals in terms of
  number and types of habitats
• Animals with jointed appendages (walking legs,
  swimming structures, claws, antennae, specialized
  mouthparts)
• Includes insects, spiders, crayfish, crabs

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Characteristics of Arthropods

• Exoskeletona hard, external skeleton that covers
  the entire body provides for muscle attachment,
  gives support/structure to the body, protects
  against drying out and predators periodically
  shed as the animal grows by a process called
  molting

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Characteristics of Arthropods (cont.)

• Body segmentation insects have 3 main body
  regions spiders have 2
• Open circulatory system
• Nervous system consists of a nerve cord and
  ganglia (the brain)

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Charcteristics of Arthropods (cont.)

• Well-developed sense organs such as antennae and
  compound eyes
• Respiratory system consists of gills in aquatic
  animals and lung-like structures in terrestrial
  forms

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Arachnids

• Includes spiders, daddy longlegs, scorpions,
  ticks, mites, and chiggers (the larval form of a
  red mite)
• Body consists of 2 main body regions
• 4 pair of walking legs (8 legs total)
• Have fang-like structures used in getting prey
• Have appendages used to hold and chew food most
  arachnids feed on insects and other arthropods

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Arachnids (cont.)

• Respiration is usually by book lungs
• Many spiders have silk glands in their abdomens
  which secrete a protein substance used in making
  webs spinnerets are structures used to spin the
  substance into webs, which are used for trapping
  prey and/or as nests
• All spiders have poison glands used in capturing
  food, but only a few produce poisons that are
  toxic to humans

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Poisonous Spiders in Our Area

• Black Widowproduces a neurotoxin that interferes
  with nervous system transmission
• Brown Recluseproduces a hemotoxin that causes
  tissues to die

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Centipedes

• 100-legged animals (they dont really have that
  many legs)
• Terrestrial found under rocks or wood
• Have a flattened body, a head, an elongated trunk
  with many segments, and one pair of legs per
  segment
• Carnivorous feed on insects and other small
  animals have poison claws just behind the head
• Move rapidly

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Millipedes

• 1000-legged animals (they also dont really
  have that many legs)
• Terrestrial also found under rocks or wood
• Have a cylindrical body, a head, an elongated
  trunk with many segments, and two pair of legs
  per segment
• Herbivorous feed on living and decomposing
  plants
• Move slowly

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Crustaceans

• Includes lobster, crayfish, shrimp, and crab
• Mainly marine, but a few freshwater
• Body consists of 2 main body regions
• 5 pair of walking legs (10 legs total 2 are
  claws)
• Have mandibles, or jaws, for biting and grinding
  food

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Crustaceans (cont.)

• Have 2 pair of sense organs for touch and taste
  antennae and antennules
• Have large eyes
• Have appendages used to hold food
• Respiration is with gills
• Green glands are excretory organs found in the
  head

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Crustaceans (cont.)

• Nervous system consists of ganglia and a nerve
  cord
• Sexes usually separate the male uses specialized
  appendages to transfer sperm to the female the
  eggs hatch into larvae, which go through a series
  of molts and stages before reaching adulthood

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Insects

• The most successful animals on Earth
• Most are terrestrial, but some are aquatic
• Have complex mouthparts
• Body consists of 3 main body regions
• 3 pair of legs (6 legs total)
• Usually have 2 pair of wings
• Have 1 pair of antennae

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Insects (cont.)

• Have both simple eyes and compound eyes
• Respiration is with tracheae, or air tubes
• Sexes separate fertilization is internal

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Insects (cont.)

• Development is called metamorphosis because if
  consists of a series of stages
• Incomplete metamorphosis
• egg ?nymph?adult
• Complete metamorphosis
• egg?larva?pupa?adult

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Insects (cont.)

• Many insects live in colonies/societies, with
  each member carrying out a specific function (ex.
  Bees and ants)
• Insects are not all harmful pests (ex. Bees
  produce honey other animals feed on insects
  some insects decompose dead organisms and wastes)

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Phylum Echinodermata

• Spiny-skinned animals
• Includes starfish, sand dollar, sea urchin,
  brittle star, and sea cucumber
• Have bilateral symmetry as larvae radial
  symmetry as adults
• All are marine

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Phylum Echinodermata (cont.)

• Have an internal skeleton, or endoskeleton
• Move by use of a water vascular system,
  consisting of a network of canals through which
  water circulates branches of these canals lead
  to numerous tube feet, which are used for
  movement and food-getting
• Very little development of the nervous,
  circulatory, excretory, and respiratory systems
  no brain or heart

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Phylum Echinodermata (cont.)

• Digestive system is the most advanced system
• Usually separate sexes sperm and eggs are
  released into the water, where fertilization
  occurs
• Starfish have an excellent ability to regenerate
  lost arms