CHAPTER 26 Sponges, Cnidarians, Flatworms, and Roundworms
CHAPTER 26 Sponges, Cnidarians, Flatworms, and Roundworms
Phylum Porifera (Sponges)
Characteristics: Simple body structure with no true tissues;
multicellular, (hermaphrodites—animal has both male and female structures), asymmetrical
Sessile—no movement as adults; are filter feeders (catch food as it floats through them)
Have pores that absorb water Spicules—tiny hard particles of calcium or
silicon compounds that make up skeleton
Phylum Porifera (Sponges)
Reproduction: can be asexual (budding) or sexual by releasing sperm that enters other sponges through pores where it will fertilize the egg. After fertilization, larvae will develop.
Larvae are immature stages of an animal.
Sponge Reproduction
SpermSpermcellscells
LarvaeLarvae
EggEggcellcell
FlagellaFlagella
New spongeNew sponge
Sponges
Review Questions
1. What word means that a sponge does not move?
Sessile
2. How do sponges eat? By filtering the water around them 3. What tiny, hard particles make up the
sponge skeleton? Spicules
Phylum Cnidaria and Cnetophora Characteristics
Radial symmetry with true tissues; cup/bell shaped
Have stinging cells called nematocysts to help capture food
Sting can be fatal to humans
examples: hydra (very tiny jellyfish-like animal), jellyfish, coral, sea anemones
Cavity
Bud
Disc Outer cell layer
Jellylike layer
Inner cell layer
Tentacle
Mouth
Has one body opening made of two layers of cells
Body Form of Cnidarians
Has 2 life forms during their life cycle: Polyp- has a tube-shaped body with a
mouth surrounded by tentacles.Medusa- has an umbrella-shaped body
called a bell.
Polyp
Medusa
Reproduction in Cnidarians
Reproduction: Sexually and asexually through budding
Review Questions
1. What type of symmetry do cnidarians have?
Radial2. What are nematocysts? Stinging cells 3. Give an example of a cnidarian. Coral, jellyfish, sea anemone,
hydra 4. What are the 2 life forms of a cnidarian? Polyp & medusa
Phylum Platyhelminthes “Flatworms”
Characteristics Simplest animal with bilateral symmetry;
have long, thin flat bodies. Usually hermaphroditic.
Many are parasitic (ex: tapeworms, liver flukes)
Phylum Platyhelminthes “Flatworms”
Reproduction Usually hermaphroditic and reproduce
sexually. During mating, they fertilize each other at the same time.
Some can reproduce asexually by regenerating (regrowing) lost parts. (ex: cut planarian: will grow back lost parts!)
Flatworms
Life Cycle of a Flatworm
Adult flukesAdult flukes
Embryos Embryos releasedreleased
LarvaLarva
Snail hostSnail host
LarvaLarva
Human Human hosthost
Phylum Nematoda “Roundworms” and Rotifera
Characteristics Bilateral symmetry, have both mouth and
anus Live in soil, fresh and marine water. Nematodes: roundworms that are often
parasitic Examples: Ascaria (intestinal roundworm about
1 ft long), hookworms, trichinella (from undercooked pork), pinworms, heartworms
Phylum Nematoda “Roundworms” and Rotifera
Reproduction Most have separate sexes. Lay eggs.
Hookworm infections are common in Hookworm infections are common in humans in warm climates where they humans in warm climates where they walk on contaminated soil in bare feet.walk on contaminated soil in bare feet.
FYI: Roundworm parasites of FYI: Roundworm parasites of humanshumans
Hookworms cause Hookworms cause people to feel weak and people to feel weak and tired due to blood loss.tired due to blood loss.
Pinworms are the most common human Pinworms are the most common human roundworm parasites in the United States.roundworm parasites in the United States.
FYI: Roundworm parasites of FYI: Roundworm parasites of humanshumans
Pinworms are highly contagious because eggs Pinworms are highly contagious because eggs can survive for up to two weeks on surfaces.can survive for up to two weeks on surfaces.
FYI: Ascaris Eggs of Ascaris are
found in soil and enter a human’s body through the mouth.
Ascaris worm coming out of a pig.
Phylum: ANNELIDA ANNELIDA “Segmented worms”“Segmented worms”
Beard worm Christmas tree worm
- Also have: (turn to pink sheet)
Setae—external bristles for movement
Coelom—true fluid-filled body cavity
Ex: Earthworms, leeches
Earthworms loosen soil and make it better for growing plants
Reproduction Sexual: hermaphrodites
(have sperm and eggs), cannot fertilize themselves.
Description: (PG.16 Purple Sheet)
Bilateral symmetry, segmented body, closed circulation (have vessels) and true digestive system, oxygen diffuses through skin
Phylum: ANNELIDA ANNELIDA “Segmented worms”“Segmented worms”
CHARACTERISTICS:Body Temp - Ectothermic
Symmetry - Bilateral Digestive System –
CompleteSkeletal System – None
Circulatory System – Closed
Reproductive System – Sexual
Heart Chambers – Heart Body
Earthworm
Leeches
Mollusks• Class Gastropoda (snails & slugs)…2nd largest class after Class Insecta
• Class Bivalvia “Bivalves” (scallops, oysters, clams, mussels)
• Class Cephalopoda (squid & octupi)…Only mollusks with brains!
Phylum: MOLLUSCA*from Latin word, “molluscus” -
soft
Description:*2ND Largest Phylum of
Animals 3 Main Body Parts:
1. Muscular foot 2. Head 3. Visceral mass (its insides) FYI: terrestrial and marine
Reproduction Sexual: most have
separate sexes, produce gametes
Giant clam
Sea Slug
Phylum: MOLLUSCAMOLLUSCA
CHARACTERISTICS:
Ectothermic Symmetry - BilateralDigestive System –
CompleteSkeletal System – None
Circulatory System – *OPEN*
Reproductive System – Sexual
Nervous System - SimpleHeart Chambers - 2 or
3 in some
Squid
Nautilus octopus
o Subphylum Crustacea (lobsters, crabs, crayfish…GILLS)o Class Insecta (all insects have 6 legs) o Class Arachnida (spiders & scorpions…all have 8 legs)o Class Diplopoda (millipedes)o Class Chilopoda (centipedes)
Arthropods
Phylum: ARTHROPODA ARTHROPODA “Arthropods”“Arthropods”
Crabs
Bull Ant
Description:• Have segmented appendages (joints) that allow for flexibility
•Molting—since exoskeletons do not grow, arthropods have to shed exoskeleton and form new one
Phylum: ARTHROPODA ARTHROPODA “Arthropods”“Arthropods”
Crabs
Bull Ant
Description:• Mandibles—mouthparts for holding, chewing, sucking, biting
•Have segments fused into three main body sections: head, thorax, abdomen; a fusion of the head & thorax = cephalothorax
- Oxygen obtained through: gills, tracheal tubes, or lungs
Metamorphosis—series of 4 changes in shape and body structure during development.
Incomplete metamorphosis—only has 3 stages; once such an insect hatches, it looks almost like the adult version and is called a nymph
• Many have camouflage to blend in with surroundings
Locust molting
Lobster
“Evil” Butterflies
CHARACTERISTICS:
Body Temp - Ectothermic
Symmetry - BilateralDigestive System –
CompleteSkeletal System –
ExoskeletonCirculatory System –
OpenReproductive System –
Very diverseNervous System -
SimpleHeart Chambers –
Muscular Tube
A termite mound made by the cathedral termite
The Arachnids: Ticks & Mites
Tick American House Mites
Egyptian Sea Star Sand Dollars
Description: Move with tube feet—
appendages with suction cups on tips
FYI: Have mouth, stomach, intestines, but no head/brain
All echinoderms have exoskeletons made of calcium carbonate.
Reproduction Sexually with
gametes, asexually with regeneration
Feather
Star
Spiny Cushion Sea Star
Phylum: Echinodermata Echinodermata “Echinoderms”“Echinoderms”
CHARACTERISTICS:
Body Temp - Ectothermic
Symmetry - Radial Digestive System –
CompleteSkeletal System –
ExoskeletonCirculatory System –
OpenReproductive System –
Sexual & asexualHeart Chambers – No true
heart