Warm Up: Describe some ways that we group invertebrates based on their “body plan” Symmetry, tissue, body cavity, development (protostome vs deuterstome)

Diversity of Invertebrates (Sections 23.3-23.6)

Objective Checklist Describe the major characteristics of invertebrates: Members Structure Feeding Movement Reproduction Evolutionary milestone

Introduction Invertebrates are animals that lack a backbone They account for 95% of known animal species

Porifera Ex: Sponges Asymmetrical, collection of animal-like protists Filter feed Sessile Asexual budding & regeneration OR sexual Multicellular

Azure vase sponge (Callyspongia plicifera) Fig. 33-4 Food particles in mucus Flagellum Choanocyte Choanocyte Osculum Azure vase sponge (Callyspongia plicifera) Spongocoel Phagocytosis of food particles Pore Figure 33.4 Anatomy of a sponge Water flow

Cnidaria Ex: jelly fish, hydra, anemones, coral Soft bodies with stinging cells, radial symmetry

Cnidaria Food is brought into gastrovascular cavity by tentacles; incomplete digestive tract Motile medusa; sessile polyp Asexual through budding or sexual True tissues; nerve net and contractile fibers Polyp Medusa

Platyhelminthes Ex: flatworms (planarians, flukes, tapeworms) Unsegmented worms with flattened bodies; acoelomate Mouth parts vary; incomplete or absent digestive tract Crawl using muscles Asexual regeneration or sexual Bilateral symmetry Flukes - Schistosomiasis /ˌʃistəsɵˈmaɪəsəs/ (also known as bilharzia)[1] is a disease caused by parasitic worms of the Schistosoma type. It may infect the urinary tract or intestines. Symptoms may include: abdominal pains, diarrhea, bloody stool, or blood in the urine. In those who have been infected a long time, liver damage, kidney failure, infertility, or bladder cancer may occur. In children it may cause poor growth and difficulty learning.[2] The disease is spread by contact with water that contains the parasites. These parasites are released from freshwater snails that have been infected. The disease is especially common among children in developing countries as they are more likely to play in infected water. Other high risk groups include farmers, fishermen, and people using infected water for their daily chores. Diagnosis is by finding the eggs of the parasite in a person's urine or stool. It can also be confirmed by finding antibodies against the disease in the blood.[2] Methods to prevent the disease include improving access to clean water and reducing the number of snails. In areas where the disease is common entire groups may be treated all at once and yearly with the medication praziquantel. This is done to decrease the number of people infected and therefore decrease the spread of the disease. Praziquantel is also the treatment recommended by the World Health Organization for those who are known to be infected.[2] Schistosomiasis affects almost 210 million people worldwide,[3] and an estimated 12,000[4] to 200,000 people die from it a year.[5] The disease is most commonly found in Africa, Asia and South America.[2] Around 700 million people, in more than 70 countries, live in areas where the disease is common.[6][5] Schistosomiasis is the parasitic disease that has the second greatest economic impact, the first being malaria.[7]

Nematoda Ex: Roundworms (hookworms, whipworms, pinworms, etc) Worm with tough exoskeleton; central nervous system Sharp mouth parts; complete digestive tract Whip-like using muscles Sexual reproduction Psuedocoelom

Mollusca Ex: Gastropods (snails), Bivalves (clams) and Cephalopods (squid) Soft-bodied; some have shells Rasping mouth parts, or filter feed

Mollusca Muscular foot or squeezing propulsion Sexual reproduction Coelom (bathes organs in blood) in some Aside: Cephalopods have closed circulatory and well developed brain

Annelida Ex: Earthworms, leeches, and marine worms Segmented, coelomate, closed circulatory system, brain Most eat organic waste; complete digestive tract

Video: Earthworm Locomotion Annelida Crawl using muscles Asexual fragmentation followed by regeneration or sexual reproduction Body segmentation Video: Earthworm Locomotion

Arthropoda Ex: arachnids, crustaceans, centipedes, insects 2/3 known species of animals are arthropods!!! Ex: arachnids, crustaceans, centipedes, insects Exoskeleton made of chitin; segmented body, brain and sense organs

Arthropoda Eat organic matter; mouth parts vary Jointed appendages; fly, swim, crawl, jump Sexual; eggs or live young Jointed appendages

Arthropods Aside on respiration Spiracles, trachea, gills, and/or book lungs. Open circulatory system

Arthropoda Aside on Metamorphosis Incomplete metamorphosis - The young resemble adults but are smaller Complete metamorphosis - Larval stage looks entirely different form the adult stage

Echinodermata Ex: Seas stars, sea urchins, sea cucumbers Radial symmetry(bilateral as larvae though) Complete digestive tract; filter feed, graze on algae, or prey on other animals Sessile or slow moving Asexual regeneration and sexual Deuterostome

Echinodermata Aside on Sea Star Structure Endoskeleton made of calcium - based plates Water-vascular system to store water and to fill the tube feet for movement Each arm has nerves, digestive and reproductive organs

The End!