Transcript Segmented worms - Aurora City Schools

Kingdom Animalia
Phylum: Annelida
Pg 672-735
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P. Annelida- Annelids
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15000, species of segmented worms
Bilaterally symmetrical
True coelom, divided into parts, one segment
disabled  other functions
• Setae (SEET-ee) external bristles
• Parapodia – fleshy protrusions
Divide into three classes based on parapodia
1. Oligochaeta (AHL-uh-goh-KEET-uh)
2. Polychaeta – (PAHL-i-KEE-tuh)
3. Hirudinea- (HIR-yoo-DIN-ee-uh)
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Class Polychaeta
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2/3 of all annelids are members
Many bristles, help move
They have antennae and mouthparts
Marine habitats
Strong jaws (predators) eat small animals
Feed on sediment as they burrow
Or use tentacles to search ocean floor
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Class Hirudinea
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Smallest class of annelids
500 species of leeches
Fresh water, moist vegetation on land
No setae or parapodis
Has sucker that attaches to surfaces- movement
Ability to swim
Carnivores, small invertebrates (parasites)
Secret an anesthetic prevents host from feeling
Secret substances that prevents blood clotting
Ingest 10xs its own weight
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Class Oligochaeta
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“few bristles” and few setae on segment
Live in soil or fresh water
Have no parapodia
Earthworm
Adaptations that enable this animal to a
burrowing life?
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Class Oligochaeta cont.
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Structure and movement
- divided into more than 100 segments
- circular and longitudinal muscles
- movement possible by segments, slinky
2. Feeding and digestion
- ingest soil as they burrow, sucked into mouth by the
muscular pharynx passes down the esophagus to
the crop to the thick muscular part called the
gizzard anus
Role is to decompose dead leaves and other organic
materials release nutrients into the soil
Loosen the soil for plants
Allow air to penetrate into the soil
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Class Oligochaeta cont.
3. circulation- closed system
blood goes toward the posterior end by a
ventral blood vessel and then to the
anterior end by the dorsal blood vessels
Five muscle tubes, aortic arches- link the
dorsal and ventral blood vessels near the
anterior end of the worm
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Class Oligochaeta cont.
4. Respiration and excretion
Gas exchange goes directly through the skin
Only if the skin is moist
Nephridia-excretory tubules that helps
eliminate cellular wastes and excess water
Other wastes are released from the body by
pores on the ventral surface
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Class Oligochaeta cont.
5. Neural Control
Chain of ganglia connected by the ventral nerve cord
Cerebral ganglia- process info from sensory
6. Reproduction- hermaphrodites, but can not fertilize its
own egg
Mating occurs when two worms press ventral surfaces
together with anterior ends pointing in opposite
directions, they are held together by the setae and film
from clitellum (thick middle)
Sperm is secreted in the mucus and is stored in the
seminal receptacle to be later used to fertilize the egg
Baby takes 2-3 weeks before hatching
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P. Mollusca- “soft”
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Clams, snails, slugs, and octopuses
Soft bodies and hard shells
112,000 species
Sedentary filer feeders and fast moving
predators
• Complete nervous system
• Coelomates- true coelom (hollow fluidfilled cavity surrounded by mesoderm)
• Trochophore- larval stage, free-swimming
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Body plan
Divided into 2 regions:
1. head-foot2. visceral mass- contains the heart and organs of digestion,
excretion, and reproduction
TERMS:
Mantle- layer of epidermis that covers the visceral mass, secrets
calcium carbonate (shells)
Gills- gas exchange
Mantle cavity- space between the mantle and visceral mass
Do not have segmentated bodies
Bilaterally symmetrical
Ganglia- cluster of nerve cells
Radula- feeding adaptation, flexible tongue like strip of tissue covered
with tough, abrasive teeth that point backwards
(cut leaves, scrape algae, drill other snails)
Use structural differences to divide mollusks into seven classes
1. Gastropoda 2. Bivalvia 3. Cephalopoda
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Class Gastropoda
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“stomach” and “foot”
Largest and most diverse (40,000 species)
Snails, abalones, conchs- single shell
Slugs and nudibranchs- have no shell
Torsion- larval development
Open circulatory system
(gills heart tissues)
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Class Bivalvia
• Aquatic mollusks, clams, oysters, scallops
• Bivalves- have shells that can be divided in half,
connected by a hinge
• Adductor muscles are attached to the inside surface of
each valve, when it relaxes the valves opens
Each valve has 3 layers that are secreted by the mantle
1. thin outer layer- protection from outside environment
2. thick middle layer- strengthen the shell
3. smooth shiny inner layer – protects soft body
Sessile and filter feeders (No Radula)
Lack a distinct head
3 sets of ganglia:
1. mouth 2. digestive system 3. foot
Some have small eyes on mantle edge (sensory structures)
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Clams- Bivalves
• Mud or sand
• Siphons- hollow tubes
• Cilia on gills – sends water to Incurrent
siphon excurrent siphon, water
circulates inside clam (trap food)
• Separate sexes
• Shedding sperm and eggs in water
fertilization is external (trochopore)
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Class Cephalopoda
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Octopuses, squids, cuttlefishes, chambered nautiluses
“head-foot”
Free-swimming, predatory
Tentacles- with suction cups
Jaws that look like parrots beak
More advanced nervous system
Closed circulatory system
Male transfers sperm to female mantle cavity with
tentacles
• Develops from an egg to juvenile (no trochopore)
• Chromatophores- dark fluid for distractions
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P. Echinoderms (spiny skin)
• Sea stars, sand dollars, sea urchins, and sea
cucumbers
• Shallow coastal waters 10,000 m deep
• Vary in size
• Bright colors
• Radially symmetrical
• No head or cephalization
• Have a bilateral symmetry larva
• Deuterostomes – (anus first)
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4 major characteristics
1. Radial symmetry called pentaradial- body parts
extend from the center along five spokes
2. Endoskeleton composed of calcium carbonate
plates known as ossicles
3. Water-vascular system- network of water0filled
canals inside their body
4. Small movable extensions of the watervascular system called tube feet – they aid in
movement, respiration, feeding, excretion
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Classes
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C. Crinoidea- kri-NOYD-ee-uh “lily-like”, sea lilies, feather stars
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C. Ophiuroidea- OH-fee-yoor-OYD-ee-uh “snake tail” basket
stars and brittle start, largest class
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C. Echinoidea – EK-uh- NOYD-ee-uh “spin like” sea
urchins and sand dollars, have ridged exoskeleton
called a test
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C. Holothuroidea- HOH-loh-thuh-ROYD-ee-uh “water polyp”
sea cucumbers
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C. Asteroides AS-tuh-ROYD-ee-uh “star like” sea star or starfish**
economically important because they feed on oysters, clams
(human food)
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Asteroides AS-tuh-ROYD-ee-uh
Sea star or star fish
1. External structure–
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composed of several arms (5- 24)
Two rows of tube feet under each arm
Body is flattened
Oral surface- mouth side, under side
Aboral surface – opposite to mouth side
Covered with short spines
Tiny pincers called pedicellariae, keep it free
from of foreign objects
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Asteroides AS-tuh-ROYD-ee-uh
Sea star or star fish
2. Water-Vascular SystemNet work of water-filled canals that are connected
to the tube feet
a. Water enters through pores in the madreporite
(sieve-like plate on aboral surface)
b. Water passes down the stone canal- tube that
connects the madreporite to the ring canal
(encircles the mouth)
c. Radial canal carries water to the tube feet
(valves keep it from flowing back up)
d. Ampulla- sacs on feet contract forcing water
into the feet
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Asteroides AS-tuh-ROYD-ee-uh
Sea star or star fish
3. Feeding and digestion
a. mouth short esophagus cardiac stomach
( can turn inside out through its mouth when it
feeds) pyloric stomach (connects to a pair of
digestive glands in each arm) nutrients are
absorbed into the coelom by walls of digestive
cavity and excess is excreted by anus on aboral
surface
b. they are carnivores, mollusks, worms
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Asteroides AS-tuh-ROYD-ee-uh
Sea star or star fish
4. Other body systems
a. no circulatory, excretory or respiratory
organs
b. gas exchange and waste excretion by
diffusion in walls of tube feet and skin gills
c. no head and no brain
d. have a nerve ring and radial nerves
e. nerve net and touch-sensitive cells
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Asteroides AS-tuh-ROYD-ee-uh
Sea star or star fish
5. Reproduction and development
a. separate sexes
b. each arm has a pair of ovaries or testes
c. 200 million eggs in one year
d. external fertilizatione. fee-swimming larva bipinnaria
f. 2 months metamorphosis
g. regenerate arms, long time
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P. Arthropoda “jointed foot”
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Segmented animals
Appendages
Exoskeleton (protection and support)
High degree of cephalization
Compound eyes- has many light detectors
All have open circulatory system
Molting- sheds its exoskeleton and make a new one
Divided into five subphyla on basis of differences in
development and in the structure of appendages
1. Trilobita 2. Crustacea 3. Chelicerata
4. Myriapoda 5. Hexapoda
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Subphylum Crustacea
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38,000 known species, vary in size
Ocean, lakes, rivers, and land
Some sessile, some have legs, swim
Have two pairs of antennae
Pair of jawlike chewing mouthparths (mandibles)
Skin to gills for respiration
Embryo becomes a free-swimming larva called a
naupius
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Crayfish
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Order Decapods “ten feet”
Have five pairs of legs – locomotin
External structurea. two major sections1. abdomen- 6 segments
2. cephalothorax-head(5)thorax(8)
Tagmata- segments fused together to make one larger
structure
b. antennae- 2 pairs, feelers, taste
c. chelipeds- back legs with pinchers
d. swimmerets- create water currents and function in
reproduction
e. telson/uropods- posterior end is paddle like tail
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Crayfish cont:
2. digestion- esophagus to stomach where
teeth grind food into paste and the
digestive glands secret enzymes for
digestion and absorption extra exits anus
3. respiration- feather like gills, as it walks
legs circulate water across gills
4. circulation- open circulatory system
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Crayfish cont:
5. Excretion- water is removed by excretory organs
called the green glands
dilute fluids are excreted by a pore at the base of
the antennae
6. Neural control/ sensory organs- similar to
annelids
Have pair of ganglia, sense vibration and chemical
in water by sensory hairs, compound eye
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