Animals : protostomes

2 divisions of protostomes

Lophotrochozoans and ecdysozoans

Lophotrochozoans

Grow by gradual additions to the body mass and have a spiral cleavage.

Ecdysozoans

Animals that most and include the arthropods and many other phyla.

Deuterostome divisons

deuterostome include chordates and echinoderms. they consist of fewer phyla and species than protostomes. They are more uniform in many ways, despite great differences.

Lophotrochozoa

Embryos develop using spiral cleavage. most live in water and move using cilia or contractions of the body musculature for movement.

Trochophore

Free living larva

Lophophore

A horseshoe shaped crown of ciliated tentacles surrounds the mouth for filter feeding.

Ecdysozoa

Contains animals that molt. two large groups contains arthropods and nematodes.

Exoskeleton

Hard external skeleton.

Phylum: Platyhelminthes ( flatworms )

Includes marines and freshwater planarians and parasitic flukes and tapeworms. Simple bodies no circulatory or respiratory systems, but complex reproductive system. Only one opening to the digestive tract.

Blood flukes

Attach within host body by sucks, anchors or hooks. Life cycle may have 2 or more hosts. Eg. Schistosoma.

Phylum: Rotifera

Bilaterally symmetrical, unsegmented pseudocoelomates. Conspicuous rings of cilia at anterior end that is used for locomotion and sweeping food into the mouth.

Phylum: Mollusca

High diversity ( second only to arthropods ). some have a shell, some do not. Range in size from microscope to huge. Evolved in the oceans, and most groups have remained there. This includes snails, slugs, clams, octopuses and others.

Mollusca - body plan ( Mantle )

Has a thick epidermal sheet. Bounds mantle cavity and secrete shell ( if there is one )

Mollusca - body plan ( Foot )

Primary means of locomotion for many and divided into arms pr tentacles in cephalopods.

Mollusca - body plan ( Shell )

Protects against predators and adverse environments. This is secreted by outer surface of mantle and typically shell has 2 layers of calcium carbonate.

Mollusca - body plan ( Radula )

Rasping, tongue-like structure used in feeding. This is used to scape up algae. it’s in predatory gastropods, modified to drill through clam shells.

Classes of mollusks

Gastropoda, Bivalvia, Cephalopoda

Gastropoda

Primarily a marine group, but some can be found in freshwater and on land ( they are the only terrestrial mollusks ). Most have a single shell - some lost it. Mantle cavity and anus are moved from the posterior to the front. Eg. Snails and slugs.

Bivalvia

Most marine and some are freshwater. They have no radula or distinct head. They have 2 shells ( valves ) that are hinged together. water enters through inhalant siphon and exits through exhaling siphon. Eg. Clams and oysters.

Cephalopoda

Onlu mollusks with closed circulatory system. Foot has evolved into a series of arms equipped with suction cups. They have been like jaws and have the largest relative brain sizes among invertebrates.

Phylum: Annelida

Segmented worms - body built of repeated units which allows for specialization.

Annelida - body plan

Head has well developed cerebral ganglion - brain. Many of the species have eyes and segments divided internally by septa ( each segment has a pair of excretory organs, a ganglion and locomotory structure ). They have a closed circulatory systems.

Phylum: Nemertea

About 2400 species of cylindrical to flattened very long worms. Most are marines; very few species live in fresh water and humid terrestrial habitats. Eg. ribbon worms.

Phylum: Bryozoa

Also called “ moss animals “. Bryozoans are small and live in colonies. May deposit calcium carbonate ( formed reefs in past ).

Phylum: Brachiopods

Have two calcified shells. Lophophore lies on the body, between the shells. Extends lophophore to feed. Eg. Lamp shells.

Phylum: Nematoda

Bilaterally symmetrical and unsegmented. covered by a flexible, thick cuticle that is melted as they grow. Digestive system is well developed and piercing organs near their mouths. Eg. Vinegar eels and eelworms.

Phylum: Arthropoda

By far the most successful animals. well over 1.2 million species and is divided into four extant subphyla ;

• chelicerata

• crustacea

• hexapoda

• Myriapoda

Anthropoda: Chelicerata

Anteriors appendages ( Chelicera ) are specialized as inners or fangs. Eg. spiders, mites and ticks.

Anthropoda: Crustacea

Mouthparts are mandibles; appendages are biramous ( “ two branched “ ); the head has two pairs of antennae. Eg. Lobsters,crabs and shrimps.

Anthropoda: Hexapoda

Mouthparts are mandibles; the body consists of three regions: A head with one pair of antennae, a thorax and an abdomen appendages are uniramous ( “ single branched “ ). Eg. Insects.

Anthropoda: Myriapoda

Mouthparts are mandibles; the body consists of a head with one pair of antennae, and numerous segments, each bearing paired uniramous appendages. Eg. Centipedes and millipedes.

Anthropoda - segmentation

In some classes specialized into magmata ( functional units ). Eg. Head, thorax and abdomen.

Anthropoda - Exoskeleton

Made of chitin and protein. protects against water loss. Must undergo ecdysis - melting.

Anthropoda - Jointed appendages

May be modified into antennae, mouthparts or wings. this can be extended and retracted.

Anthropoda: Chelicerata - Anterior

— Prosoma bearing all appendages

• Pedipalps and 4 pairs of walking legs.

Anthropoda: Chelicerata - Posterior

— Opisthosoma contains reproductive organs

Anthropoda: Crustacea - Tagmata

Cephalon and thorax fused to form a cephalothorax.

• 2 pairs of antennae, 3 pairs of appendages for chewing and various pairs of legs.

Hexapoda: Coleoptera

• two pairs of wings, the front one hard, protecting the rear one

• biting and chewing mouthparts

• complete metamorphosis

• Beetles

Hexapoda: Lepidoptera

• Two pairs of broad, scaly, flying wings

• Tubelike, sucking mouthparts

• complete metamorphosis

• Butterflies

Hexapoda: Diptera

• Front flying wings transparent and hindwing reduced to knobby balancing organs called halters.

• Sucking piercing or lapping mouthpats

• complete matamophosis

• Flies

Hexapoda: Hymenoptera

• two pairs of transparent flying

• chewing and sucking mouthparts

• complete metamorphosis

• Bees, wasps and ants

Hexapoda: Hemiptera

• wingless or with two pairs of wings

• piercing, sucking mouthparts, with which some draw blood

• simple metamorphosis

• True bugs, bedbugs and leafhopper.

Hexapods: Orthoptera

• wingless or with two pairs of wings

• biting and chewing mouthparts in adults

• Simple metamorphosis

• Grasshoppers and crickets

Hexapoda: Odonata

• Two pairs of transparent flying wings that cannot fold back

• chewing mouthparts

• simple metamorphosis

• Dragonflies

Hexapoda: Isoptera

• Two parts of wings, but some stages wingless

• chewing mouthparts

• simple ( and incomplete metamorphosis ).

• Termites

Hexapoda: Siphonaptera

• wingless

• piercing and sucking mouthparts

• complete metamorphosis

• Fleas

Anthropoda: Myriapoda - centipedes

One pair of appendages per segment.

Anthropoda: Myriapoda - Millipedes

Two pairs of appendages per segment.

• each segment is a tagma of 2 segments.