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