Ch 26 Identification Practice

Portuguese Man-o-WarColonial Cnidarain

ElephantiasisCaused bya parasitic roundworm

- filaria

Crown Jellyfish - medusa -

Cnidarian

Marine Flatworm Platyhelminthes - showing

bilateral symmetery

RoundwormsRoundworms areare

EVERYWHEREEVERYWHERE!!!!NematodaNematoda

Platyhelminthes (flatworms)- have simple organs and exhibit

simple cephalizationPlanarian (left) showing it’s ocelli (eyespots) and marine flatworm

(right)

Soft Coral PolypsCnidarian - showing radial

symmetry

c. Proglottid - flatworm (Platyhelminthes - Tapeworm

• Platyhelminthes (flatworms) are the first animals on the phylogenetic tree that have simple organs. They have very primitive “brains” in their “heads”-called cephalization

a. Sac Body Plan – only one opening for food to enter and

wastes to exitPlanarian on left

(Platyhelminthes) and Hydra on the right (Cnidaria)• What do these

animals have in common?

Roundworm infectionHeartworm

Guinea Worms - Break out of skin when mature

Parastic Roundworms

Acoelomates (left), Pseudocoelomates(right), and

Coelomates(middle)

Hydra - a polyp cnidarian - may be showing budding the

the bottom right corner

• Found in the tropics• Nearly ¼ of the

population are infected with hookworm

• The eggs hatch and develop outside the body of the host

• Burrow into un-protected skin (often the feet) and enter the blood stream

• Travel from the lungs up to the pharynx and are swallowed

• They dig into the intestinal wall and suck the blood of the host

• cause weakness and poor growth

Hookworm

Sea anemones (polyp Cnidaria)

Regeneration - asexual repro.Exhibited by

Planaria (PlatyhelminthesFlatworm

Sexual

Reproduction of a Jellyfish - is a

medusa Cnidarian (adult) - shows

sperm, egg, planula swimming larva (with bilateral symmetry), the young and then

budding polyp stage, and the adult medusa

Sea Anemones - a polyp, sessile Cnidarian

Clownfish and Sea Anemone – symbiotic relationship –tentacles protect clown fish from predators, clownfish protects tentacles from being

eaten

Trends in Animal Evolution - Body Plans

Sea anemones

Platyhelminthes - planaria top right and left, marine flatworm bottom

right

`Tapeworm (a parasitic Flatworm) Life cycle

PoriferaSea

Sponge

A Polyp Cnidarian - showing itsnerve net

Acoelomate - exhibited by Platyhelminthes (Planaria top

left)

Planaria - Pharynx Protruded (ready to eat)(Platyhelminthes - Flatworm)

• Parasitic Flatworm -

• You can tell because this is not really a mouth - it is just a “hook” to stick to the intestinal wall

• Deceiving because it looks round

loaded

Discharged

What is this?

NemaotcystOf a Cnidarian’sStinging Tentacles

Flatworm showing its

nervous system (you can just see

the two ventral nerve cords)

and the gastrovascular cavity (larger

branching network)

Blood Flukes -

• Parasitic flatworm• Have two different hosts

in their life cycle• Found in tropical areas• Female lives inside the

male in a groove• Often kills human host

Nematocysts - on the stinging tentacles of Cnidaria

• Blood Fluke life cycle - parasitic flatworm - snail is intermediate host - often kill human host

• Trichinella worm CYSTS - Parasitic Roundworm (but very difficult to tell the difference between this and tapeworm (a flatworm) cysts)

• Food or water contaminated with eggs is ingested by an intermediate host (cow, pig, fish)

• Larvae from eggs burrow into muscle tissue of host and create a cyst

Asexual Reproduction - budding - Hydra - a Polyp

Cnidarian

Tapeworms showing proglottids and the scolex

Anatomy of a Roundworm• Simplest animals with a digestive system with two

openings – a mouth and an anus• Have several ganglia-groups of nerves-but lack a brain• Muscles run in strips along the length of the body walls• Breath and excrete their metabolic wastes through their body

walls

Parasitic Roundworm

Top - Pseudocoelomates,shown by roundworms

• Bottom is comparing acoeloms, pseudocoeloms and coeloms

mesoderm

Trends in Animal Evolution - Symmetry

• Sponges! (Porifera carcasses!)

Trends in Animal Evolution – Cephalization - flatworm on

left, Roundworm on right