Introduction to the Animal Kingdom

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Introduction to the Animal Kingdom

• Emphasis on Invertebrates those animals without
  an internal skeleton

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Study Sheets

• The grid for the animal phyla
• http//cstl-csm.semo.edu/waterman/bs218/protected/
  animal_kingdom_form.htm
• A sheet organizing key concepts with questions
• http//cstl-csm.semo.edu/waterman/bs218/protected/
  animalstudysheet.htm

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Instructions for using this powerpointBring to
class on Tues. 12/2

• Use your text, chapter 25, along with the handout
  grid of major trends in animal kingdom
• Fill in your grid
• Note the definitions of terms on your study
  sheet, terms such as symmetry, body cavity, as
  they come up.

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• Kingdoms of Organisms

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Key features of all AnimaliaPut this info on
your Six Kingdoms chart

• All are truly multicellular (large) organisms
• There are no cell walls, just a plasma (cell)
  membrane
• Digestion occurs within the organism (internal)
• Ecologically they are heterotrophic and work as
  consumers and decomposers
• Diseases caused by animals include worms, lice,
  and injury due to bites.
• Arthropods (insects and ticks) carry many viral
  and bacterial diseases but most do not themselves
  cause disease.

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Animal Phyla Invertebrates
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Major Trends in Animal Phyla

• In the next slide you will see Figure 25.3 in
  your text. This is the organizer for this
  powerpoint, it will be shown repeatedly.
• It shows a family tree for the animals, with
  major phyla across the top, with those oldest in
  the fossil record to the left.
• Above each branch point in the tree, a new
  adaptation is listed. All the animals along and
  above that branch have that adaptation. E.g.,
  all animals above the branch for sponges have
  tissues. Sponges do not.

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Fig. 25.3 Major Evolutionary Trends in Animals
Most recent
Oldest phylum
All above this point have tissues, all below do
not. Porifera are below.
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Practice reading the tree shown in previous slide.

• 1) Which animals do NOT have a body cavity?
• 2) Which is the first animal phylum to have
  segmentation?
• 3) Which animal phylum is the most recent to show
  bilateral symmetry?
• 4) What major trends do rotifers have?
• Answers on the next slide

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Answers

• 1) Porifera, Cnidaria, Platyhelminthes (flat
  worms)
• 2) Annelida
• 3) Chordata (our phylum)
• 4) Body cavity, bilateral symmetry, tissues,
  multicellularity

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Sponges Porifera
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Fig. 21.2
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Porifera

• Simplest of animals
• Multicellular
• No symmetry
• No tissues (a tissue is a sheet of similar cells
  doing a single function).
• Digestion is internal in specialized cells

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Symmetry

• An organism has symmetry if it can be split in
  the middle and the two halves are mirror images
  of each other. Look at your hands. One is the
  mirror image of the other.
• We humans are bilaterally symmetric. That means
  we can be split in half in only one direction,
  like the squirrel. Notice that the blue and red
  planes do not give two equal halves. Only the
  green plane does

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Radial Symmetry

• Some animal phyla show radial symmetry.
• That means they are built on a circular plan,
  kind of like a pizza. There are many ways to cut
  a pizza and get two equal halves.

Here is a Cnidarian called a sea anemone. It can
be cut up like a pizza and make 2 equal halves.
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Porifera

• Sponges are asymmetric. That means they have no
  symmetry. They cannot be split into two equal
  halves by any single plane.

A dead sponge, such as we use in the bath or to
put on cosmetics. What you see here are the
mineral deposits and connective materials laid
down by the once-living sponge.
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Porifera Internal digestion takes place in
choanocytes lining the inside of the sponge
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Cnidaria The Jellyfish and Corals
Hydra, above
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Fig. 21.2
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Cnidarians Found in Fresh and Salt Water
(includes animals that make coral reefs)

• Portuguese man-of-war
• is an example
• Radially symmetric
• Several layers of tissues
• Stinging cells
• Digestive cavity lined with digestive tissue
• Incomplete digestive system (only a mouth, no
  anus)
• Has a nerve net, but no central brain
• No Body cavity

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What the heck is a Body Cavity?

• A body cavity is a space inside the body within
  which the major organs are located.
• We humans have a large body cavity in our torso.
  If you open us up, you find a space. Inside that
  space are our lungs, heart, stomach, liver,
  intestines, etc.
• Most animals have a body cavity, sometimes it is
  called a coelom.
• The Cnidaria do not have such a cavity. They
  dont even have organs!

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Flat Worms (Platyhelminthes) Fresh and Salt
Water animals
Fluke (left) Planarian (below) Did you see this
guy in lab?
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Fig. 21.2
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Flat Worms e.g. Planaria

• First to have organs and organ systems
• Nervous, reproductive, urinary
• First to be cephalized
• Incomplete digestive track be sure to locate
  the mouth!!!!
• First with bilateral
• symmetry
• No body cavity

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Cephalized??????

• To be cephalized means to have a head end (and a
  tail end).
• Flatworms are the first animals to have a head
  end.
• Think about what is in your head big brain,
  lots of sensory input
• In the flatworm the head end has a brain, some
  light sensitive spots (no images, just light and
  dark) and those things that stick out and look
  like ears are really for sensing chemicals (like
  our tongues and noses).
• Cool.

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Round Worms
Heart worms (left and in a heart, center) Free
living nematodes (soil and water) shown below
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Fig. 21.2
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Round Worms

• Bilateral symmetry
• Complete digestive track
• (first to have a tube starting with a mouth and
  ending with an anus)
• Has body cavity which contains the digestive
  system (gut) and reproductive systems.
• Some of these are pathogenic to other animals or
  to plants.

Above is a cross section through a worm to show
body cavity
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Molluscs Squid, Octopus, Snails and Clams (and
slugs, ugh)
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Fig. 21.2
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Molluscs

• Bilateral symmetry
• Complete digestive track
• Body cavity contains three chambered heart in
  snails. Coelom is a fancy name for body cavity.
• Some have gills
• Edible examples include Oysters, clams,
  escargots, scallops, octopus, calamari, squid

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Figure from your book to show internal structures
of a mollusc
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Annelids segmented worms

• Earthworm (right) and bloodworm (left)

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Fig. 21.2
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Annelids

• Segmentation is first seen in this phylum.
• Segmentation means that the body is divided into
  parts, in the earthworm, the parts are very
  similar to each other.
• You are a segmented organism. Look at your
  fingers each one has three segments.
• Advantage of segmentation repetition and the
  greater chance that segments will mutate into
  something useful (e.g., a finger or a forearm, or
  a backbone).

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Internal structure showing organs and
segmentation. Note 5 hearts
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Arthropods Jointed Legs
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Fig. 21.2
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Arthropods

• Exoskeleton The skeleton is outside the body.
  These animals must molt.
• Jointed appendages
• (an example of segmentation)

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Echinoderms Spiny Skin
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Fig. 21.2
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Echinoderms

• Internal skeletons when young
• Bilateral symmetry INSIDE each arm. Focus on
  this.
• Deuterostomes
• Closest to Chordates

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Deuterostomes???

• Okay, so animals develop from zygotes into a
  hollow ball called a blastula.
• Next, a part of the ball pushes in. This place is
  called the blastopore. It begins to form the
  digestive cavity.
• Imagine pushing your finger into a partially
  blown up balloon. See how you get two layers.

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Deuterostomes, continued

• Eventually, in most animals, the pushed-in place
  goes all the way through to form a complete
  digestive track.
• If this pushed in place (blastopore) becomes the
  mouth, the animal is a protostome. (proto
  first, stome mouth)
• If the blastopore becomes the anus, it is a
  deuterstome and the mouth develops at the second
  opening. (deutero second, stome mouth).
  Echinoderms are deuterostomes.
• Guess which ones chordates including humans
  are?????

Dont worry about all the terminology in this
figure.
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Summary

• At this point you should have a filled in grid
  for the invertebrate phyla of animals and study
  sheet answers. Bring those to class Tuesday for
  extra credit.
• Remember that once a major adaptation occurs
  (such as bilateral symmetry) it is carried
  forward into the more recently evolved animals.
• Next time well talk about the vertebrate
  animals, members of the phylum Chordata.