Invertebrates

Characteristics Invertebrates are animals that do not have backbones. 97 % of the animal kingdom is made up of invertebrates. Insects and some other invertebrates have exoskeletons. Symmetry

Invertebrate Phyla Sponges Cnidarians Platyhelminthes Nematodes Mollusks Annelids Echinoderms Arthropods

Sponges (Porifera) Cells relatively independent Mostly marine No Symmetry (asymmetrical) Adults are sessile no true tissues or organs (most primitive animals) have some regeneration capabilities filter feeders asexual reproduction by buds and sexual reproduction

https://www.youtube.com/watch?v=SHJOu9PjKyU&safe=active&noredirect=1 4/12/2019

Cnidarians (jellyfish, sea anemones, corals, gorgonians, hydroids) Mostly marine Radial Symmetry cells called cnidocytes, which contain stinging structures called nematocysts; used for prey capture and defense many possess dinoflagellates or green algae, resulting in a symbiotic relationship asexual reproduction by budding or sexual reproduction

Cnidarians Jellyfish Hydra Coral Sea anemone Portuguese Man-O-War

Portuguese man-of-war

Portuguese man-of-war attack

https://www.youtube.com/watch?v=bPbQs4Zc85k

Giant jellyfish

Platyhelminthes Flatworms Bilateral symmetry Unsegmented body flattened dorsoventrally possess a two-way gut move by contracting muscles (glides over rocks through water) carnivorous capable of regeneration sexual reproduction (usually hermaphroditic), some reproduce asexually by fission

Intestinal fluke

Liver flukes – white-tail deer

Planarian – freshwater flatworm

Nematodes (roundworms) No segmentation A one-way digestive tract from mouth to anus. Most are free-living; found in soil where they are important decomposers. Some are parasitic, including Hookworms, pinworms filarial worms — parasitic worms that cause: river blindness, elephantiasis, guinea worm

Mollusks Clams, snails, squids bilaterally symmetrical possess mantle which secretes the shell plates or shells large, well defined muscular foot, often with a flattened creeping sole possess a one-way gut sexual reproduction Varied habitats Marine Freshwater Terrestrial

Octopuses

Blue Ringed Octopus The most venous octopus. This small mollusc lives in warm, shallow reefs off the coast of Australia, new Guinea, Indonesia and the Philippines.  It has a life span of about one and a half years.

Nautiluses

Cuttlefishes

https://www.youtube.com/watch?v=EbubjXsA4S4 https://www.youtube.com/watch?v=t-LTWFnGmeg&feature=related 4/12/2019

Annelids Segmented worms Common earthworm Leech bilaterally symmetrical possess a one-way gut each segment contains a pair of appendages called parapodia (used for movement and gas exchange) sexual reproduction

4/12/2019

http://animals. howstuffworks http://animals.howstuffworks.com/28332-discover-magazine-leech-therapy-video.htm 4/12/2019

Arthropods External skeleton Huge variation – mostly insects bilateral symmetry, metameric segmented body, each with a pair of jointed appendages most have regional body specialization usually possess compound eyes exoskeleton made of chitin and must be shed in order to grow possess a one-way gut

Great Hairy Scorpion – largest in US (up to 6”)

Scorpion’s glow under black light

Lobsters

Barnacles

Krill

Crabs

Millipede

Grasshopper

Praying Mantis eating Grasshopper

Queen Bee

Drone Bee

Worker bee with pollen

Echinoderms means “spiny skin” exclusively marine adults have pentamerous radial symmetry – larva are bilaterally symmetrical body organized about an oral-aboral axis water vascular system composed of a complex series of fluid-filled canals (used for locomotion and respiration) sexual reproduction or asexual reproduction by regeneration