Invertebrates Chapter 29 and 30 Sponges Cnidarians Flatworms

Invertebrates Chapter 29 and 30 Sponges, Cnidarians, Flatworms, Roundworms, mollusks, annelids

Animal Kingdom Characteristics - multicellular - eukaryotic - heterotrophs - movement - tissues

Body Plans - Bilateral Symmetry- equal halves in one direction

Radial Symmetry • - 360 degrees; equal halves

- Asymmetry- cannot cut in equal halves

Body Development - Ectoderm- outside body layer- skin and hair - Endoderm- inside body layer- digestive tract

- Mesodermmiddle layer- muscles, blood and organs

- Types of Body Cavities: 1. Coelom- true body cavity - surrounded by mesoderm

-2. Pseudocoelom- false cavity - between mesoderm and endoderm

3. Acoelomate No body cavity.

Let’s Review. What type of symmetry is this?

What type of symmetry?

Symmetry?

- Vertebrates- animals with backbones - fish, amphibians, reptiles, birds, and mammals

- Invertebrates- animals without backbones - sponges, cnidarians, mollusks, worms, echinoderms, arthropods

Sponges: Phylum Porifera Asymmetrical – no symmetry No tissues or organs (cells work together to perform a specific function 2 body layers: endo-, ecto Sessile – do not move Variety of shapes and colors Acoelemate – no body cavity

Variety of Sponges

Digestion of sponges Sponges are consumers Feed on bacteria, algae, protozoans (filter feeders)

Sponge digestion continued:

Reproduction Either sexual or asexual Asexual- fragmentation- each piece of sponge will grow into a complete new sponge Sexual- hermaphrodite- produce both eggs and sperm- release into water at different times-sperm from one enters pores of other to fertilize eggs- External fertilization

Reproduction continued Produces a zygote- free swimming larvae for a short time- attaches to surface- new sponge

Cnidarians- the stingers Coral

Characteristics of Cnidarians Two Types: n n Polyp – sessile, tube-like with tentacles ex. Coarl, sea anemone Medusa – free swimming, umbrella shaped n Jellyfish Has tissues – ecto-, endo. Nematocysts – stinging cells on tentacles Radial symmetry acoelamate

B

How Cnidarians Get O 2? Diffusion Have nervous tissue.

Reproduction Asexual- budding- small extensions of body grow and then breaks away from parent Sexual-some species are hermaphrodites n Others, female releases egg and male releases sperm into water- External fertilization

hydra

Portugese Man of War (colony)

Jelly fish

Sea anemone

Sea Anemones

Coral reef

Coral reefs Structure See diagram – oldest part is deeper. Newest is toward the top. Live symbiotically with unicellular yellow brown algaezooxanthellae

Benefit of Symbiotic Relationship: Coral gets: food (coral can also capture food with tentacles) Algae gets: Protection and access to sunlight

Coral Bleaching When coral ejects it’s algae- coral turns white Coral doesn’t get enough food- dies

Coral bleaching due to: Diseases Increased Ultra violet radiation Sedimentation Pollution Increased water temperatures Direct destruction by humans- anchors, touching while diving

Bleached coral

Flatworms Acoelomate Bilateral symmetry

Platyhelminthes – flatworms

Characteristics of flatworms: Can be parasitic, or free living 1 body opening Hermaphrodites or asexual reproduction by regeneration: breaking in 2, and each becomes a new organism Get O 2 through skin- diffusion

Tapeworm Body Two parts: n n Scolex – head Proglottids – body sections Attach to inside of intestines Parasite Ex. Beef tapeworm: become infected by eating raw beef.

Getting Beef tapeworm:

Blood fluke - causes Schitomiasis

Planeria Eyespots- light Pharynx- extends like a straw, releases enzymes- breaks down food , sucks it up Sensory pits on side of head, detect food, chemicals, and movement Ability to regenerate

planeria

29 -4 Roundworms Pseudocoelum Tube within a tube body 2 body openings Move in a side to side manner parasites

Ex. Ascaris - hookworm Carried through human waste to soil If ingested eggs enter large intestine – becomes larvae Larvae bore through blood vessels Back to the intestine to mate

Ascaris in pig intestine

Trichinella – pork roundworm Causes Trichinosis Eating improperly cooked pork

Lymphatic Filariasis

Mollusks and Annelids Chapter 30

Mollusks Characteristics n n Invertebrates Larval stage Marine, freshwater, terristrial coelomates

Mollusks have 3 parts to body: Visceral mass – contains organs Mantle – tissue around visceral mass (secretes a shell) Foot - locomotion

Other Mollusk characteristics: Exoskeleton n Sometimes called a valve Outer skeleton

• Radula (not in bivalves) Tongue-like structure

Organ systems of mollusks: Excretory – get rid of waste: Open Circulatory System –heart pumps fluid through a series of vessels out into body cavity

Organ Systems of Mollusks Reproduction – most have separate sexes, external fertilization Respiration – use gills

30 -2 Groups of Mollusks Bivalves – “two valves” Valves held together by strong muscles No radula Filter feeders Examples: clams, oysters, scallops

Bivalve Photos

Gastropods Examples are snails and slugs Single shell or none Use radula to scrape food off of rocks etc Land snails – hermaphrodites, aquatic snails – separate sexes Herbivores Gills or lungs?

Cephalopods – “head footed” Examples: squid, octopus Large head with tentacles Eyes Marine predators (consumers) Ink sac – for protection Internal shell – pen Brain present – complex Skin can change color gills

Phylum Annelida Segmented worms Examples: earthworms, leeches, sandworms Segmented body Coelum Bilateral symmetry Abundant in all habitats

Organ Systems in Segmented Worms Closed circulatory system Excretory system – nephridia Breath through skin Bristles – setae Reproduction – hermaphrodites

Digestion of Earthworm Pathway of food: n n n Pharynx – soil enters Esophagus Crop-storage Gizzard- muscular for grinding soil Intestines – absorption anus

Groups of Annelids Marine segmented worms

Leeches