Animal Diversity

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Animal Diversity
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Types of Symmetry in Animals
2) This sponge is asymmetrical. You could not cut
it any way to make two equal halves

• Asymmetrical organisms can not be divided into
  any number of parts which are exactly the same or
  are mirror images of each other.
• Bilaterally Symmetrical organisms can be divided
  along one central axis, resulting in mirror image
  halves.
• Radially Symmetrical organisms can be divided
  into more than two

3) Bilateral and Radial Symmetry
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Types of skeleton

• Exoskeleton hard outer casing
• Insects and spiders.
• Protection from predators
• Must be shed to grow
• Endoskeleton internal skeleton

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Segmentation

• Multiple body units
• Earthworms most segments are identical.
• Arthropods (more advanced) specialized segments
  head, abdomen, thorax

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Body Covering

• Fur
• Feathers
• Scales
• Shells

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Body Appendages

• Legs
• Tentacles
• Antennae
• Jointed appendages

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Porifera

• Their body cavity, called a spongocoel, is lined
  by cells called choanocytes.
• Choanocytes are special cells used for feeding.

6) Here we see the porocytes on the sides of the
sponge and the large osculum at the top.

• Porifera are sponges.
• They have pores.
• They remain fixed in one place.
• Sponges do not have distinct tissues.
• Porifera are asymmetrical

7) Choanocytes on the inside. Three barbed
spicules in walls of sponge.
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Cnidaria

• hydras, jellyfish, sea anemones, and corals.
• They are two cell layers thick.
• They have a gastrovascular cavity with one
  opening for food intake and waste expulsion.
• Tentacles form a crown around the opening to
  catch food.
• Cnidocytes cover the tentacles and contain stings
  called nematocysts. The nematocysts quickly come
  out to stab when the cnidocytes are touched by
  prey or enemies. Some nematocysts also contain
  poison.

They are radially symmetrical
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• Polyp type cnidarians like sea anemones and
  hydras remain fixed in one place with their mouth
  facing up.
• Hydra
• Medusa type cnidarians like jellyfish move around
  with mouth facing down.
• jellyfish

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Platyhelminthes

• Platyhelminthes are flatworms
• with a gastrovascular cavity with one opening
• Waste and gas is exchanged through diffusion at
  the body surface
• They are mostly parasitic
• Flatworms are bilaterally symmetrical
• Tapeworm, Planaria.

11) This turbellaria lives in the sea. You can
see its eye spots.
12) This is the pharynx of a Planarian.
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Nematoda
13) These strongyles infect horses.
14) Gross!

• Nematoda are roundworms
• Have both a mouth and anus.
• They are bilaterally symmetrical
• Thread-like
• Many are parasitic
• Hookworm

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Annelida

• Annelida are bilaterally symmetrical, segmented
  worms.
• Segments are mostly not specialized
• Gas is exchanged at the body surface and moved
  through the body in blood vessels.
• They have a nervous system and circulatory system
• Earthworms, leaches

15) This fanworm is a polychaeta.
16) Here you can clearly see the segments in this
leech.
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Echinodermata
24) This blue linkia starfish is of class
Asteroidea. It has 5 legs.

• Echinodermata are usually radially symmetric.
• Spiny exoskeleton
• They have a water vascular system which consists
  of passages and tube feet controlled by the
  movement of water. The tube feet help echinoderms
  move, eat, and breathe.
• Starfish, sea urchin, sea cucumber

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Mollusca

• Mollusca are bilaterally symmetrical or
  asymmetrical and unsegmented.
• Soft bodes, mostly protected by a shell.
• They have a muscular foot, a visceral mass around
  the innards, and a mantle which secretes a hard
  shell.
• Clams, snails, squid

18) A gastropod, sea snail. Its muscular foot is
frilly and red.
17) A snails anatomy
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Arthropoda

• Arthropods are bilaterally symmetrical and
  segmented.
• Segmentation of the body allows for jointed
  appendages.
• Arthropods have an exoskeleton made of protein
  and chitin.
• They have a open circulatory system.
• Arachnida eight legs, two body parts, no
  antennae
• Spiders, ticks, scorpoin

21) This spider is an arachnid chelicerate.
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• Crustacea gills for breathing, two pairs of
  antennae, jointed legs with claws
• Crab, lobster
• Insecta six legs, three body parts, one pair of
  antennae

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Chordata

• Chordates have a notochord during the embryonic
  stage. It is a flexible rod in the place of the
  backbone, usually replaced by the backbone and
  skeleton in adult chordates.
• The embryos have a dorsal hollow nerve cord,
  which becomes the central nervous system.
• They have pharyngeal slits, adapted for
  breathing, jaw support and hearing.
• They have a muscular, postanal tail. This
  remains in aquatic chordates for swimming.
• Chordates are usually bilaterally symmetrical.

26) Most chordates have vertebrae like this one.
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Fish

• Mostly have bony skeleton
• Gills
• Scales
• Two-chambered heart
• Salmon, trout

30) This is a ray-finned bony fish.
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Amphibia
31) What a handsome little tree frog! But what if
his bubble were to burst?

• frogs, salamanders, and toads
• live in moist areas and lay their eggs in water
  to survive.
• The keep their skin wet for better gas diffusion.
• Amphibians go through metamorphosis from tadpole
  to adult. Develop lungs
• Three-chambered heart

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Reptilia

• Lungs
• Dry Scales
• Lay eggs with hard covering
• Endothermic
• Mostly three-chambered heart

32) These diamondback terrapins are being
released into the wild.
33) Diamond-back terrapins were a favorite treat
for early Americans. They have recently been
taken off the protected lists.

• turtles with hard shells.
• lizards and snakes.
• alligators and crocodiles.

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Aves

• Aves are birds, with feathers made of keratin and
  wings for flight.
• Birds bones are mostly hollow to be lighter in
  flight. They also lack some organs and teeth.
• Birds are endothermic. They have efficient lungs
  and complicated breathing patterns to ensure a
  good supply of oxygen while flying.
• Four chambered heart
• Wings beat by contraction of chest muscles
  attached to the sternum by a keel.
• Lay eggs with shell

34) Hummingbirds must beat their wings
continuously to fly and are the only birds that
can hover.
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Mammalia

• Mammals are endothermic
• Hair
• feed young with breast milk
• usually give birth to live young.
• Placental mammals provide unborn young with
  nutrients by a placenta.
• Monotremes, like platypuses and echidnas, lay
  eggs. Hatched monotremes drink milk from
  nippleless mothers.
• Marsupials, like kangaroos and koalas, give birth
  babies so early and small they may not even know
  they gave birth. Most marsupials carry their
  young in pouches.

35) Elephants are good mammal parents, taking
care of their children.