Animal Diversity 2

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Animal Diversity 2

• Multicellular, eukaryotic, heterotrophic
  organisms
• that feed by INGESTION

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Body symmetry
Radial symmetry
Bilateral symmetry
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Bilateral symmetry
Dorsal
Anterior
Posterior
Ventral
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Tissue organization
2 tissue layers Radially symmetric
3 tissue layers Bilaterally symmetric
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Two tissue layersEndoderm and Ectoderm
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Ectoderm
Endoderm
Gut
Ectoderm
Endoderm
Gut
Ex Hydra
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Three tissue layersEctoderm, Mesoderm, Endoderm
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Ectoderm External Layer Skin cells of
epidermis Neurons of brain
Mesoderm Middle Layer Cardiac muscle, Skeletal
muscle,Kidney cells, Red blood cells, Smooth
muscle in gut
Endoderm Internal Layer Lung (Alveolar)
cells Thyroid cells Pancreatic cells
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Body cavity
Acoelomate
Eucoelomate
Pseudocoelomate
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Nematoda

• Most abundant animal on Earth
• Pseudocoelomate
• Up to a million different species (only like 50k
  described)
• 15,000 species are described as parasitic
• Sheds proteinaceous cuticle
• LOTS of investment in reproductive organs

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Body cavity
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Nematodes as parasites

• Case study Trichinosis

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Phenotypic Plasticity
Spikes in response to predation
Mouth parts changing in response to environmental
conditions.
Up-regulation of chemical deterrents in response
to herbivory.
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Arthropoda

• Animals with exoskeleton, segmented body, and
  jointed appendages
• Exoskeleton is periodically shed
• Four subphyla Cheliceriformes, Myriapoda,
  Crustacea, Hexapoda
• Exoskeleton is mainly chitin
• First organisms to fly unoccupied niche (air)
  allowed for massive radiation

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Cheliceriformes

• No antennae, no jaws
• Pincer-like appendages called chelicera used for
  grasping and fragmenting food

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A word on horseshoe crabs.

• Not crustaceans.
• 2 primary compound eyes, 7 secondary simple eyes
• Hemocyanin carries oxygen instead of hemoglobin
  (they have blue blood due to high levels of
  copper)
• Only arthropod with broadcast spawning
• Totally weird.

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Myriapoda
Millipedes 2 pairs of legs per segment Detritivore
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Centipedes 1 pair of legs per segment Predators
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Crustacea

• Biramous (two-parted) limbs (even barnacles)
• Most are free-living aquatic animals
• Some (e.g. pill bugs) are terrestrial
• Some (e.g. barnacles) are sessile

Ex Crustacean claws branch into 2 segments
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Crustacea

• Daphnia have five pairs of biramous thoracopods
  (thorax appendages)

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HexapodaSix-legged arthropods
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External insect anatomy
3 distinct body units head, thorax, and abdomen
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Insect head Search for compound eyes, ocelli,
antennae, labrum, mouthparts
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Insect mouthparts Mandible, maxilla, labium
Evolution of mouthpart morphology
Chewing mouthparts (e.g. grasshopper)
A Chewing B Lapping (e.g. bee) C Siphoning
(e.g. moth) D Sucking (e.g. mosquito)
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Arthropod respiration Tracheal system
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Final notes

• No labs next week.
• Then only two more labs
• - Animal Diversity 3 (chordates and starfish)
• - and then a final lab practical
• (no lecture for the last lab)
• I will post a study guide this week on
  thinkbiologically.com
• Dont forget to turn in your proposals on Monday
  the 19th!