animal diversity and evolution
TRANSCRIPT
Animal Diversity I
Animal characteristics
Distinct set of genes that uniquely control body plans different from fungi and plant body plans
Heterotrophs Develop from a fertilized egg Internal means to digest food Motile in at least one stage of
life cycle
Phylum Porifera Sponges
Spicules: gives structure and is a form of defense to predators
Mostly asymmetrical Sessile (immobile) adults, free-swimming larvae 2 cell layers:
Outer cell layer is the epidermal layer Inner cell layer is lined with choanocytes flagellated
cells used to bring in food and water through ostia Brings food and water inside via ostia (filter feeder) Expels waste and water via osculum
Phylum Porifera Filter feeding in sponges
Phylum Porifera Observe slide of Grantia or Scypha
Phylum Cnidariasea jellies, sea anemones, and corals
Two body forms, many show both forms during their lifecycle: Sessile polyp Motile larva and medusa
Sac-like gut with one opening (no anus)( Dead End digestive tract)
Have radial symmetry Two cell layers (diploblastic):
Ectodermic layer Endoderm layer
Stinging nematocysts along tentaclesto capture prey and for defense
Phylum Cnidaria Nematocysts
Phylum Cnidaria Typical life cycle
Major Classes of Cnidarians
Hydrozoa Hydroids (hydra-like),
some are jelly-like Scyphozoa
True sea jellies Anthozoa
Includes corals and sea anemones
Lack medusa phase, polyps only
Phylum Cnidaria Hydra: observe slide
Observe two tissue layers (diploblastic): ectoderm endoderm
Single opening for feeding and extruding waste
No free-swimming medusa phase
Phylum Cnidaria Obelia: observe medusa and polyp slide
medusa stage polyp stage
LOPHOTROCHOZOA
Organisms having a lophophore (a specialized tentacle structure) or have a trochophore larval form
Protostomes: have mouth and anus, but mouth forms before the anus
Bilateral symmetry Complete digestive tract (except Platyhelminthes) Three distinct cell layers (triploblastic):
Ectoderm, mesoderm, and
endoderm
Lophophore of a brachiopod
Trochophore larva (annelids and mollusks)
Phylum PlatyhelminthesFlatworms, planarians, flukes, and tapeworms
Only have one opening for digestive tract Can be parasitic, carnivorous, or herbivorous Advances include:
More specialized tissues Several, well-developed organ
systemsCephalization: development of a
headLocalization of sense organs
First group to have bilateral symmetry
Phylum Platyhelminthes Diversity within Platyhelminthess
Flatworms Mostly free-living:
predators or scavengers (dead, organic matter)
Many are brightly colored Cilia or muscular
movement Planarians
Free-living: feed on small animals or scavenge
Cilia for movement
Phylum Platyhelminthes Diversity within Platyhelminthes
Flukes Parasitic in liver, lungs, bladder, or blood vessels
of vertebrates Primary host for adult fluke: vertebrate Intermediate host for larvae: usually a snail
Tapeworms Specialized parasites for life in intestine (pre-
digested food) Attach to host by scolex (suckers & hooks)
Phylum Platyhelminthes Observe slide of liver fluke, Opisthorchis
Parasitic flatworm
Phylum Platyhelminthes Tapeworms
Phylum Annelidasegmented worms, marine worms, earthworms, leeches
Advancements Segments: repeating units Hydrostatic skeleton: fluid filled
cavity in which pressure can be changed to allow the animal to move
Setae (bristles) for movement Simple diffusion for gas exchange
(no respiratory system) Well-developed digestive,
circulatory, reproductive, and nervous systems
Phylum Annelida Class Polychaeta: bristle worms
Mostly live in marine environments
Have many setae (bristles) that extend from their parapodia (appendages)
Typically either filter feeders or carnivorous
Phylum Annelida Class Oligochaeta: earthworms
Found in terrestrial & freshwater habitats
Herbivorous or detritivorous
Few setae and no parapodia
Hermaphroditic Observe prepared slide Dissect Lumbricus
Phylum Annelida Lumbricus (earthworm) dissection
Basic anatomy terms Anterior: head end Posterior: tail end Dorsal: back Ventral: belly
Pin anterior end to dissecting pan Cut body open along the anterior-posterior axis Separate body wall from animal and pin to dissecting
pan Use water to flush body cavity
Phylum Annelida Class Hirudinea: leeches
Live in marine, freshwater, and terrestrial habitats
Leeches have no bristles and no parapodia
Can be free-living (carnivorous) or parasitic
Phylum Molluscachitons, snails, slugs, clams, octopus, squid, nautilus
Body plan Muscular foot Visceral mass: contains
organs(digestive, circulatory, reproductive) and is protected by a hard
outer shell Mantle that secretes protective shell Gills to obtain oxygen from water Head with sensory structures
Very advanced in cephalopods
Phylum Mollusca Class Polyplacophora: chitons
Marine omnivores that scrape algae and other organisms with radula
Clings tightly to rocks with foot
Phylum Mollusca radula
Phylum Mollusca Class Gastropoda: snails and slugs
Name means “stomach foot”
Radula for feeding Glide by moving
muscular foot Some slugs have
aposomatic coloration (warning colors)
Are either carnivorous or herbivorous
Phylum Mollusca Class Bivalvia: clams, mussels, scallops, oysters
2-part shell Foot used for
anchoring and burrowing
Do not have a head, radula, or eyes
Use gills for oxygen and filter-feeding
Phylum Mollusca Class Cephalopoda: squid, octopus, nautilus
Name means “head foot”
Lack outer shell (except nautilus)
Uses modified mantle to jet through the water
Use tentacles to capture prey
Very complex sensory systems
Squid tentacle with hooks
ECDYSOZOA
Protostomes These organisms have an exoskeleton Must molt in order to grow Complete digest tract Bilateral symmetry Three distinct cell layers:
Ectoderm Mesoderm Endoderm
Phylum NematodaRoundworms
Can be parasitic or free-living (carnivorous or herbivorous)
One of the most widespread and diverse animal Complete digestive system, has a mouth and an anus False body cavity present
Filled with reproductive organs No protective lining around organs, but some
separation of organs Some parasites of plants and animals Observe prepared slide Dissect Ascaris
Phylum Nematoda Ascaris dissection
Use same techniques used for dissecting Lumbricus Make comparisons between the two dissected
specimens
Phylum ArthropodaChelicerates, myriapods, hexapods, and crustaceans
Arthropods united by having: Segmentation
Basic body plan:
head, thorax, abdomen Exoskeleton
Made of chitin, molt to grow Jointed paired appendages
Used for feeding, movement, senses, and reproduction
Subphylum Crustacea Shrimp, lobsters,
barnacles, and relatives Subphylum Chelicerata
Spiders, mites, and ticks Subphylum Myriapoda
Millipedes and centipedes
Subphylum Hexapoda Insects and relatives
Phylum Arthropoda Subphyla of Arthropoda
Crustacea: crayfish
Chelicerata: tarantula
Myriapoda: centipede
Hexapoda: beetle