-
Characteristics
of Flatworms (Platyhelminthes)
- •Marine, freshwater, moist
- terrestrial
- •Some free-living, many parasitic
- •Bilaterally symmetrical, acoelomate
- •Incomplete gut
- •Sensory organs
- •No organ systems
- •Asexual and sexual reproduction
- •They are flat
- •
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Platyhelminthes
Reproduction
- •Monoecious (hermaphroditic)
- •Sexual
- –“Penis Fencing”
- (yup, it’s really called that)
- •Asexual
- –Fission,
- budding, regeneration
- –
-
Phylum
Platyhelminthes:
Parasites
- •Parasite of vertebrates
- •Adapted for parasitism
- –Organs
- for attachment
- –Glands
- produce secretion for attachment
- •Often have:
- –Protective
- body covering
- –Complex
- life cycle involving 2 or more hosts
- •Examples include
- –Schistosoma
- (blood fluke), which has a snail intermediary
- –Tapewormsin
- beef or pork
- •
- –
- •
-
-
Characteristics of Annelids
- •Ubiquitous (moist)
- •Includes
- –Oligocheates(earthworms),polychaetes(marine
- worms), leeches
- •Brain with ventral nerve cord
- •Complex sensory organs
- •Coelom functions as hydrostatic
- skeleton
- •Can be both Monoecious (hermaphroditic) or dioecious (separate sexes)
-
Annelid
Anatomy
- •Segmented body
- •Complete digestive system (mouth
- and anus)
- •Closed circulatory system
- •Respiration through diffusion or
- gills
- •Excretion through nephridia (kidneys)
- •
-
-
Characteristics
of Molluscs
- •Mantle and muscular foot
- •Ubiquitous
- •Complex digestive system
- •Radula
- •Nervous system with sensory organs
- •Sexual reproduction
- •Hemocoel - open circulatory system
- with
- heart, blood vessels, blood
- •Trochophore larvae
- •Sensory organs including complex
- eyes
- •Mono- and dioecious
-
The
Mantle
- Molusc
- •
Gas exchange - –Respiratory
- organs/surfaces
- •Excreta location
- –Products
- of digestion released here
- –Eggs/sperm
- released here
- •Aquatic organisms
- –Water
- pumped through by cilia
- –Sensory
- organs
- •Cephalopods (squid, octopuses)
- –Mantle
- is muscular
- –Used
- in locomotion
- •Secretes shell (and makes pearls!)
-
Gastropods:
Snails and Slugs
- Molusc
- •“stomach foot”
- •Largest, most diverse class of molluscs
- •Sessile or sedentary
- •Can be shell-bearing
- •Operculum for closing shell
- •
-
What’s
that shell for?
- Molusc
- •Protection
- –Predation
- –Water
- loss
- –Environmental
- fluctuations
- •
- •Features of the shell:
- –Usuallydextral or
- right-handed
- –Grows
- with the animal
- –Sometimes
- has pores for water/gas exchange
- –
- •Why do the shells coil?
-
Gastropod
Diet
- Molusc
- •All use the radula
- •Scrape algae off rocks
- •Break seaweed
- –abalone
- •Drill holes through bivalves
- –moon
- snail
- •Cilia in gills collect particles
- –Limpets,
- slipper snails
- •
-
Bivalves
- Molusc
- •“Two-shelled”
- •Sedentary
- •Suspension feeders
- •No radula
- •Little cephalization
- •Mostly marine, some freshwater
- •Sensory organs
- •Siphons and/or muscular foot
-
Bivalve
Reproduction
Molusc
- •Separate sexes
- •External fertilization (mostly)
- •3 larval stages
-
Ecological
Importance of Bivalves
- •Invasives
- –Zebra
- mussel
- •Filter water
- •Disease
- –Paralytic,
- Amnesic, Neurotoxic Shellfish Poisoning (~30 deaths/
yr) - –Vibrio
- (~100 deaths/
yr) - •Economic/Food
- –Aquaculture
- in CT alone several $million/
yr - –Geoducks
-
Cepholopods
- Molusc
- •
“head foot” - •Squid, octopus, nautilus,
- cuttlefish
- •All marine
- •Size varies greatly
- •Predaceous
- –Fish,
- other
molluscs,- crustaceans, worms
- •Highly mobile
- •Some venomous
- •Jaws with radula
- •Arms or tentacles with or without
- suckers
- •Large brain (intelligent!)
- •Complex eyes
- •
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Cephalopod
Reproduction
- Molusc
- •Dioecious
- •Male produces spermatophore
- •Often elaborate mating
- “performances”
-
Cephalopod
Behavior
- •Complex brains and eyes
- •Tool-using octopus
- •Mating rituals
- •Ink production for defense
-
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Characteristics
of Arthropods
- •Jointed, often specialized
- appendages
- •Ubiquitous
- •Coelomates
- •Exoskeleton of chitin
- •Freeliving and parasitic
- •Complex organ systems
- •Complex behavior
- •Open circulatory system
- •Metamorphosis
-
Arthropod
“Success”
- •Body permits movement and agility
- •Complex sensory abilities,
- including compound eyes
- •Complex behaviors
- •Adaptation to a wide range of
- habitats
- •Every feeding adaptation including
- parasites
- •
-
Arthropod General
Anatomy
- •Body divided into functional
- regions
- –Head
- –Abdomen
- –
Thorax - •Appendages
- –Paired
- and specialized
-
Arachnids
- Arthropods
- •
Simple eyes - •Sensory hairs
- •8 pairs legs
- •Carnivorous
- •Includes:
- –Spiders
- –Scorpions
- –Ticks
- and Mites
-
Myriapods
“many-footed”
- Arthropods
- •
Centipedes - –Predators of earthworms, insects
- –1 pair legs/segment
- •Millipedes
- –Herbivores
- –2 pairs legs/segment
- •
-
Insects
- •Largest group of arthropods
- •3 pairs of legs
- •Many fly: 2 pairs wings (usually)
- •Specialized mouthparts
- •Specialized appendages
- •Includes
- –Butterflies and moths
- –Bees, ants, wasps
- –Beetles
-
Crustaceans
- Arthropods
- •“shell bearing”
- •Lobsters, crabs, barnacles
- •Primarily aquatic
- •Free-living or parasitic
- •Have gills
- •Sensory antennae
- •Economic importance
- •
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