Phylum Annelida
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Transcript Phylum Annelida
Segmented Worms
Diversity
Live in all parts of the world (except Arctic and
antarctic regions)
Can be marine, freshwater, or terrestrial
Approximately 9,000 species
Range in size from 1mm- 11 Feet
Common Earthworm is 9-10 inches
Known as segmented worms
Ex: leech, earthworm
Characteristics of All Annelids
Body System: Tube within a tube
Inner tube is the straight line digestive tract
Extends from mouth (first segment) to anus (last
segment)
Outer tube consists of two layers of muscle, moist
skin, a cuticle, and secretion of slimy mucous
Fluid filled cavity between the two tubes
Contains a well developed circulatory system
Nervous system
Thread like kidneys
Reproductive organs
Characteristics of All Annelids
Bilateral Symmetry
Metamerism (segmentation)
Increases the efficiency of body movement
Allows for greater complexity of the body
systems
Muscular Structure
Both longitudinal and circular muscles
Surrounded by moist cuticle (outer covering)
which aids in breathing
Characteristics of All Annelids
Setae
Used for locomotion
Leeches do not have these
Coelom is well developed
Circulatory system is closed
Digestive System is complete
Respiratory System
Gas exchange occurs through skin, gills, or
parapodia
Characteristics of All Annelids
Excretory system
A pair of nephridia
Nervous System
Double ventral nerve cord and pair of ganglia
Sensory System
Taste buds, photoreceptor cells and eyed with
lenses (in most)
Reproductive System
Hermaphroditic or separate sexes
May have asexual reproduction
Classification
Kingdom Animalia
Phylum Annelida
Class Oligochaeta
Examples: Earthworms
Class Polychaeta – means many bristles
Examples: lugworms, clam worms, bristleworms
Approximately 8,000 species
Class Hirudinea
Examples: leeches
Often used in medicine to relieve swollen limbs, dry
skin, etc.
Worm composting
Recycling the organic waste of a household into compost
allows us to return badly needed organic matter to the
soil
Worm composting is a method for recycling food waste
into a rich, dark, earth-smelling soil conditioner.
Worm compost is made in a container filled with
moistened bedding and redworms
Add your food waste for a period of time, and the worms
and micro-organisms will eventually convert the entire
contents into rich compost.
Composting DIY
Class Oligochaeta
Earthworms:
•Burrow in soil
•Come out at night to explore
•Can drown if soil gets too wet
•Diet: scavengers (eat dead,
decaying matter)
•Have the ability to learn!
Class Polychaeta
Polychaetes:
•Ex: Christmas tree worm,
Fireworm, Scaleworm
•Largest group of annelids
•Mostly marine
•Brightly colored or can
be dull in color
Class Hirudinea
Leeches:
•Live mostly in freshwater
•More abundant in
tropical areas
•Most are carnivorous
(feed on meat, blood)
•Have two brains!
Characteristics of Earthworm (most
“famous” of Annelids)
Soil is natural habitat
Burrows head first into soil (makes its burrow by using
the pointed head end to push soil aside)
Eats soil for food (obtains nutrients/water from the
soil)
Can feed on grass, leaf/scraps of organic matter
Also digest humus (dead, decaying matter)
Head end is light-sensitive
Nocturnal—feed/eat/active during nighttime
Characteristics of Earthworm (most
“famous” of Annelids)
Long, slender body (cylindrical)
150-200 ring-like segments
Locomotion/movement—performed by layers of
muscle in the body wall (circular bands of muscle)
Ventral (belly) side has setae (bristle-like hairs) used
for movement
Mature worms have a clitellum (produces the egg capsule
at breeding time)—larger segment (lighter in color)
Respiration—through its moist skin (cannot become
dry—worm would suffocate)
Characteristics of Earthworm (most
“famous” of Annelids)
Organs:
Pharynx—sucks in food (think of a vacuum)
Esophagus—food enters here once enters mouth
Crop—temporary storage (from esophagus)
Gizzard—grinds food into small pieces
Intestines—digestion and absorption occur here
Aortic arches—-part of closed circulatory system,
contains 5 of these, maintains a steady pressure of
blood to vessels
Ganglia—nervous system organ, brain
Characteristics of Earthworm (most
“famous” of Annelids)
Nerve cord—runs from ganglia to each segment,
provides nerves to body structures
Blood vessel—part of closed circulatory system, moves
oxygen throughout body
Clitellum—reproductive organ, secretes mucus, stores
eggs/sperm during reproduction
Setae—movement and reproductive purposes
Segments—mouth-anus sensory/excretory organs are
attached to muscle wall of each segment
Anus--excretion
Nephridium—excretory organ, excrete ammonia
Earthworm Dissection
YouTube Earthworm Dissection
Characteristics of Earthworm (most
“famous” of Annelids)
Other/Biosphere/Uses
Help to aerate the soil
Prepare soil with nutrients from excretory waste
products
Leeches can be used for medicinal purposes (for
blood clotting issues)
Earthworms: eat, fishing, aerate soil, etc
Earthworm Pictures!
Earthworm Pictures!