Do First

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Do First

• Grab the introductions to animals worksheet and
  the invertebrate packet

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Introduction to Animals

• Chapter 26

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What characteristics do all animals share?

• They are multicellular
• Their cells are eukaryotic and lack walls
• They are heterotrophic by ingestion
• They mainly reproduce sexually
• They are able to move

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How are Animals Classified?

• BY THE LACK OR PRESENCE OF TRUE TISSUES
• True tissues are groups of similar cells that
  perform a common function
• Ex Muscle Tissue

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How are Animals Classified?

• BY BODY SYMMETRY
• Asymmetry is the lack of body symmetry
• Radial symmetry is when body parts are arranged
  in a circle around a central axis
• Bilateral symmetry is when the body can be
  divided equally along one plane

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How are Animals Classified?

• BY THE PRESENSE AND TYPE OF INTERNAL BODY CAVITY
• 1.) Acoelomate
• No body cavity
• 2.) Pseudocoelomate
• No true body cavity
• 3.) Coelomate
• True body cavity
• Fluid-filled space b/t body wall and gut

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How are Animals Classified?

• WHETHER OR NOT THE BODY IS ASSEMBLED IN SEGMENTS

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How are Animals Classified?

• BY THE PRESENSE OR ABSENCE OF JOINTED APPENDAGES
• Joints permit powerful movement and aid in
  locomotion.
• Allow animals to perform complex movements

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How are Animals Classified?

• WHETHER THEY DEVELOP IN A DEUTEROSTOME OR
  PROTOSTOME PATTERN
• In protostomes, the mouth is formed first, then
  the anus
• In deuterostomes, the anus is formed first, then
  the mouth

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Notes

• 1. Take out your note packet
• 2. Think to yourself What is one way that
  animals are classified?

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Phylum Porifera
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Members

• Sponges the simplest animals

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Body Structure

• Asymmetrical
• No tissues or organs
• Openings called pores (or ostia) cover body wall
• Cells are suspended in jelly like layer called
  mesoglea
• Skeleton made of spicules

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Feeding

• Sponges are filter feeders they filter plankton
  from sea water
• Water enters through ostia and waste exits
  through oscula

Ostia
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Movement

• Adult sponges are sessile they are attached to
  the ocean floor and cannot move
• Larvae can swim

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Reproduction

• Asexual Budding and/or fragmentation
• Sexual
• Sperm is released and fertilizes egg that is
  retained in sponge
• Free swimming larva swims to another location
  where it remains and develops into a new adult

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Unique Characteristics

• Spicules
• Asymmetry
• Collar Cells

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Phylum Cnidaria
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Members

• Hydras Corals Jellyfish Sea anemones

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Body Structure

• Radial Symmetry
• Body composed of outside (ectoderm) inside
  (endoderm) layers
• No body cavity
• Jelly fish have hydrostatic skeleton (water
  filled cavity) that is under pressure

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Feeding

• They are predators they capture prey w/
  stinging tentacles using cnidocytes
• Gastrovascular cavity allows for 2 way feeding

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Movement

• Cnidarians have two body forms
• Medusa Free floating mushroom shaped
• Polyp Attached to rock pipe shaped

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Reproduction

• Asexual by budding
• Sexual
• Release gametes into water
• After fertilization, the larva is free-swimming
• The larva then develops into an adult

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Unique Characteristics

• Cnidocytes (stinging cells)

Nematocyst
Cnidocyte
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Phylum Platyhelminthes
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Members

• Flatworms
• Tapeworms, flukes,
  planarians

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Body Structure

• Bilateral Symmetry
• Anterior/posterior
• Dorsal/ventral
• Sense organs grouped at the anterior end
• Better to sense where you are going than where
  you have been (foreshadows brain)
• Three tissue layers (ecto, meso, endoderm) no
  coelom
• Ocelli function as eyes

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Feeding

• One opening allows for 2 way digestion
• The opening is called the pharynx and is found on
  the ventral side in the middle

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Movement

• Muscles found in mesoderm aid in movement
• Bilateral symmetry, nerves at one end (ganglion),
  and ocelli allow for movement in forward
  direction

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Reproduction

• Asexual Regeneration
• Sexual
• Many are hermaphroditic
• This characteristic is common in parasites
  why?

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Unique Characteristics

• None

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Phylum Nematoda
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Members

• Roundworms
• Ex Hookworms pinworms heartworms

Elephantiatis is caused by a type of roundworm
blocking the lymphatic system, causing limbs to
swell
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Body Structure

• Bilateral Symmetry
• Not Segmented
• Three tissue layers
• Pseudocoelom
• Nerve cells and sensory cells located towards head

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Feeding

• The digestive system has separate openings for
  feeding and waste elimination (one-way!) Not very
  differentiated
• This allows them
  to acquire more
  food, which
  increases their
  activity level

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Movement

• Long layers of muscle that pull against the
  bodys outer covering and the pseudocoelom whips
  the worms body from side to side
• Better coordinated than acoelomates

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Reproduction

• Usually reproduce sexually

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Unique Characteristics

• None

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Phylum Mollusca
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Members

• Snails, slugs, octopus, squid,
  oysters, mussels, and others

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Body Structure

• Bilateral Symmetry
• Three tissue layers with TRUE COELOM (reduced in
  size)
• Isolates the internal organs from
  body-wall movements, allowing for increased
  activity level and increased organ complexity
• Have soft bodies (some have shells)
• Not segmented
• Organ systems for excretion, circulation,
  respiration, digestion, reproduction

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Feeding

• Most have a radula which scrapes food off of
  rocks or plant matter
• Food is digested in the stomach and intestine of
  the one way digestive tract
• Wastes are passed out of the anus

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Movement

• Widely varied
• Some glide along surface (ex snails)
• Some shoot water out of a siphon to propel
  themselves or, creep along using suction cups
  (octopus)
• Some are mostly
  sessile, but can
  open and close their
  shells quickly to
  propel themselves
  (mussels)

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Reproduction

• Sexes are usually separate
• Fertilization occurs externally in most aquatic
  mollusks
• Fertilization occurs internally in most
  terrestrial mollusks and octopuses
• Larva is called trocophore

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Unique Characteristics

• Radula used to scrape food off of surfaces

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Phylum Annelida
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Members

• Segmented worms Earthworms, marine worms,
  leeches

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Body Structure

• Bilaterally Symmetrical
• Have segmentation Repeated sections of body
  that contain complex sets of body structures
• Three tissue layers
• Coelom
• Organ systems for excretion, digestion,
  circulation, sensing, etc

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Feeding

• Separate openings for mouth and anus
• Eat organic waste material
• They excrete digested material (called castings)
  that helps maintain nutrient-rich soil

Leeches are sanguivorous - they feed as blood
sucking parasites on preferred hosts.
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Movement

• Annelids use their hydrostatic skeleton to move
  from one place to another
• Their characteristic crawling motion is due to
  different sets of muscles lengthening and
  shortening at different times
• Peristalsis Video

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Reproduction

• Asexual by fragmentation
• Sexual
• Some are hermaphroditic
• Some have separate sexes

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Unique Characteristics

• None

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Phylum Arthropoda
Jointed
Feet
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Members

• Crustaceans, Spiders, Insects

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Body Structure

• Bilaterally Symmetrical
• Three tissue layers
• Coelom
• Segmented
• Covered with an exoskeleton made of chitin
• Jointed waterproof
• Well developed brain and sense organs

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Feeding

• Arthropods have a completely differentiated
  digestive system (each part as a special job)
• They can be carnivores, herbivores, detritus
  feeders, filter feeders, and parasites
• Typically, paired appendages around the mouth are
  used for collecting and handling food and are
  usually specialized according to their diet

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Movement

• Joints permit powerful movement and aid in
  locomotion
• Muscles in arthropods are attached to the
  endoskeleton across joints
• Different groups of arthropods are adapted for
  movement on land, water, in the sky

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Reproduction

• Sexes are usually separate
• Fertilization usually occurs externally
• In many species, such as spiders, the young look
  like miniature adults
• The young of other arthropod species have little
  or no physical resemblance to adults and go
  through metamorphosis

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Unique Characteristics

• Jointed exoskeleton made of chitin

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Phylum Echinodermata
Skinned
Spiny
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Members

• Sea urchins, brittle stars and sea cucumbers

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Body Structure

• Have an endoskeleton made of calcium
• Bilateral symmetry as larvae radial symmetry as
  adults
• Nervous system called nerve ring allows them to
  perform complex movements
• Have a coelom (body cavity) that functions as a
  simple circulatory and respiratory systems

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Feeding

• One-way digestion (mouth on ventral side anus on
  dorsal side)
• Echinoderms can eat by ejecting their stomachs
  out of their mouths onto a food source and
  slurping up the food source once it has been
  digested by stomach enzymes
• Sometimes, their food sources are harder to get
  to they can use their tube feet to suction open
  a prey item before digesting it

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Movement

• Echinoderms have hundreds of tube feet on their
  ventral side that act as little suckers
• The tube feet allow them to crawl along surfaces

http//www.youtube.com/watch?vKIIy0vj6wQEfeature
related
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Reproduction

• Some are hermaphroditic some have separate sexes
• Asexually Fragmentation (if an arm breaks off,
  it can develop into a whole new organism)
• Sexually Females and males release their
  gametes (eggs and sperm) into water, where
  fertilization occurs

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Unique Characteristics

• Nerve Ring
• Tube feet