Kingdom Animalia III Bugs, Slugs and Sea stars. Phyla Arthropoda, Mollusca & Echinodermata Bugs, Slugs and Sea stars. Phyla Arthropoda, Mollusca & Echinodermata

The arthropods: The joint legged animals.  Of all the Kingdom Animalia, the phylum arthropoda contains by far the greatest number of species.  The insects alone number over 1,000,000 identified species, more than all other animal phyla combined.  The beetles are the most diverse family of organisms on earth.  Of all the Kingdom Animalia, the phylum arthropoda contains by far the greatest number of species.  The insects alone number over 1,000,000 identified species, more than all other animal phyla combined.  The beetles are the most diverse family of organisms on earth.

Arthropod characteristics  All arthropods have a hard outer covering called an exoskeleton, composed of chitin.  Specialized mouth parts  Jointed legs  Compound eyes  Segmented body  Bilateral symmetry  All arthropods have a hard outer covering called an exoskeleton, composed of chitin.  Specialized mouth parts  Jointed legs  Compound eyes  Segmented body  Bilateral symmetry

Metamorphosis in arthopods  All members of the phyla arthopoda go through some sort of metamorphosis between juvenile and adult forms.  A useful adaptation since this allows the juveniles and adults to exploit 2 different resources.  Eg. Caterpillars and butterflies.  Caterpillars eat plant materials and butterflies feed on nectar.  All members of the phyla arthopoda go through some sort of metamorphosis between juvenile and adult forms.  A useful adaptation since this allows the juveniles and adults to exploit 2 different resources.  Eg. Caterpillars and butterflies.  Caterpillars eat plant materials and butterflies feed on nectar.

Arthropod classes There are several important classes within the phylum arthropoda Crustaceans: this class consists of lobsters, crabs and shrimp. Most have 5 pairs of legs and are called “decapods”. Deca=10, pods=feet. Most live in water. Arachnids: this class consists of spiders, scorpions, sulifugae, ticks and mites. Most have 8 legs. Insecta: the largest class. Insects have three body segments, jaws, and six legs. The Beetles are the largest family in this class. No insects live in salt water. There are several important classes within the phylum arthropoda Crustaceans: this class consists of lobsters, crabs and shrimp. Most have 5 pairs of legs and are called “decapods”. Deca=10, pods=feet. Most live in water. Arachnids: this class consists of spiders, scorpions, sulifugae, ticks and mites. Most have 8 legs. Insecta: the largest class. Insects have three body segments, jaws, and six legs. The Beetles are the largest family in this class. No insects live in salt water.

Arthropods

Phylum Mollusca  Molluscs are muscular soft- bodies invertebrates.  Most live in the oceans, but slugs and some snails are terrestrial.  Some possess a hard shell to protect their soft bodies.  Molluscs are muscular soft- bodies invertebrates.  Most live in the oceans, but slugs and some snails are terrestrial.  Some possess a hard shell to protect their soft bodies.

Mollusca classes  We will look at three classes within this phylum.  The gastropods: These are the snails and the slugs.  Snails have shells, slugs do not.  There are terrestrial, freshwater and marine gastropods.  We will look at three classes within this phylum.  The gastropods: These are the snails and the slugs.  Snails have shells, slugs do not.  There are terrestrial, freshwater and marine gastropods.

Gastropod information  Gastropods are the most numerous of all mollusca types. 80% of all molluscs are gastropods.  Some are grazers, some are scavengers and others are active predators.  Gastropods reproduce sexually, with many species being hermaphroditic.  Gastropods are the most numerous of all mollusca types. 80% of all molluscs are gastropods.  Some are grazers, some are scavengers and others are active predators.  Gastropods reproduce sexually, with many species being hermaphroditic.

The bivalves  Bivalves are molluscs whose bodies are protected by a strong, hinged shell.  Clams, mussels and oysters are all members of this class.  They are an important source of food for humans and other animals.  Bivalves are molluscs whose bodies are protected by a strong, hinged shell.  Clams, mussels and oysters are all members of this class.  They are an important source of food for humans and other animals.

Bivalve information  Bivalves are found in both fresh and salt water, but not on land.  Bivalves are filter feeders who siphon water into their gills and filter out nutrients.  Bivalves reproduce sexually as males and females release their gametes (sex cells) into the surrounding water.  Larval bivalves are swimmers which eventually settle down and develop their shells.  Bivalves are found in both fresh and salt water, but not on land.  Bivalves are filter feeders who siphon water into their gills and filter out nutrients.  Bivalves reproduce sexually as males and females release their gametes (sex cells) into the surrounding water.  Larval bivalves are swimmers which eventually settle down and develop their shells.

The Cephalopods  The final class of Mollusca we will consider are the cephalopods.  The cephalopods are the octopi, the squid and the nautiloids.  This class represents the most advanced molluscs as well as the most intelligent of all invertebrates.  The final class of Mollusca we will consider are the cephalopods.  The cephalopods are the octopi, the squid and the nautiloids.  This class represents the most advanced molluscs as well as the most intelligent of all invertebrates.

Cephalopod information.  Most cephalopods possess 8 tentacles which they use to help capture their prey.  All cephalopods are predators.  Nautiloids are the only cephalopods that retain a shell.  Both octopi and squid are masters are camoflage. Octopi use it to blend into their surroundings while squid often use rapid color changes to communicate with other members of their species.  Most cephalopods possess 8 tentacles which they use to help capture their prey.  All cephalopods are predators.  Nautiloids are the only cephalopods that retain a shell.  Both octopi and squid are masters are camoflage. Octopi use it to blend into their surroundings while squid often use rapid color changes to communicate with other members of their species.

More cephalopod information  Cephalopods reproduce sexually with internal fertilization.  The male passes to the female a “sperm packet” which the female uses for internal fertilization.  The female then lays eggs, sometimes numbering in the thousands.  Cephalopods reproduce sexually with internal fertilization.  The male passes to the female a “sperm packet” which the female uses for internal fertilization.  The female then lays eggs, sometimes numbering in the thousands.

Cephalopods

Phylum Echinodermata  These are referred to as the tube footed animals.  Of all the invertebrate phyla, it is the echinoderms that are most closely related to the chordates.  Internally they all have a system of hydrolic tubes which aid in their locomotion.  Sea stars, sea urchins and sea cucumbers are all examples of echinoderms.  These are referred to as the tube footed animals.  Of all the invertebrate phyla, it is the echinoderms that are most closely related to the chordates.  Internally they all have a system of hydrolic tubes which aid in their locomotion.  Sea stars, sea urchins and sea cucumbers are all examples of echinoderms.

Echinoderm information  Echinoderms reproduce sexually with external fertilization which produces a free swimming larva.  Many echinoderms, such as sea stars are able to also reproduce asexually through regeneration.  Echinoderms may be scavengers, filter feeders of plankton, or active predators.  Echinoderms reproduce sexually with external fertilization which produces a free swimming larva.  Many echinoderms, such as sea stars are able to also reproduce asexually through regeneration.  Echinoderms may be scavengers, filter feeders of plankton, or active predators.

Echinoderms