Download Invertebrates

Invertebrates
8 major Invertebrate Phyla
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Porifera- sponges
Cnidaria-sea anemones and jellyfish
Nematoda- round worms
Platyhelmenthes- Flatworms
Mollusca- snails, slugs, squids, and octopi
Annelida- segmented worms(repeated body
segments)
• Arthropoda- insects, shrimps, lobsters, and crabs
• Echinodermata- sea stars, urchins, brittle stars
Invertebrate
- Organism without a backbone
3 Main Body Plans
1. Bilateral
2. Radial
3. Asymmetrical
Bilateral
- Two sides of the body mirror each other
Radial
- Symmetry is found all around the center point
Asymmetrical - There is no line of symmetry
Invertebrate Characteristics
Ganglion
- Concentrated mass of nerve cells
- Nerves allow animal to sense environment
- All animals except sponges have nerves
Gut
- A pouch lined with cells, used to break down
food, the cells absorb the food
Coelom
- Space surrounding the gut
- Can have other organs within
Sponges- Porifera
- Simplest invertebrates
- Asymmetrical, no tissues, gut or neurons
- Live in water
- Can regenerate broken or missing parts
Regeneration
- Classified by their shapes
- Ability to grow back a body part
Pores
-Holes on the outside of body
-Water brings in food and oxygen
Osculum
-Hole on top of sponge that allows water to leave
Cnidarians
- Radial symmetry
-complex tissue and a gut
-simple nerve cells
-stinging cells
- Ex: Jellyfish, Anemones
- Two body forms: Medusa or Polyp
Medusa
- Swims through water
Polyp
- Usually attach to a surface
Classes of Cnidarians
Hydrozoans
-common cnidarians
-live in both fresh and salt water
-most spend lives as polyps
Jellyfish
-use tentacles to catch food
-spend most of lives as medusas
Sea anemones -brightly colored
-spend lives as polyps
Coral
-polyps
-brightly colored
-made of calcium carbonate
-live in colonies
-build underwater reefs
- Found in warm, tropical waters
Nematoda
Round Worms (long, slim, & round)
- Bilateral symmetry
- Simple nervous system
- Simple brain is a ring of ganglia
- Many are parasites Trichinella spiralis
- Some infect humans pinworms and
hookworms
- decomposers
Platyhelmenthes Flatworms (simplest worms)
- Bilateral symmetry
- Clearly defined head
- Two large eyespots
- Cannot see through eyespots, but sense light
- parasitic
- Microscopic
Planarian
Flukes
- 3 major classes
-Live in freshwater lakes and streams
-predators
-well developed nervous system
-parasites-feed on a host organism
-no eyespots
-contain suckers and hooks to attach to
other animals
Tapeworm
-parasites
-no gut or eyespots
-attach to the intestines of other animals
Absorb nutrients
-can infect humans
Mollusks and Annelid Worms
Mollusks
-Most live in the ocean
-some live in freshwater and land
-complex ganglia-control breathing, movement, & digestion
-contain a circulatory system- pump blood
-Bodies are made of :
-Muscular foot-used for movement
-Visceral mass- contains gut, gills,
and other organs
-Mantle-covering used for protection
if no shell, covers the visceral mass
-Shell-hard covering used for protection
from predators or land mollusks from drying
3 Classes of Mollusks
Gastropods
-slugs and snails
-eat by using a radula  tongue with curved teeth
Bivalves
- 2 shells
-clams, oysters and other shellfish
-use gills to filter food from water(tiny plants,bacteria)
Cephalopods
-Octopus and squid
-use tentacles to get food and a powerful jaw to
eat it
-contain large brain connected to ganglia
-most advanced nervous system, smartest inverte
Annelid Worms
-segmented worms
-bodies are in segments  identical repeating
body parts
-bilateral symmetry
-circulatory system
-Complex
nervous system with brain
-Live in salt water, freshwater or on land
-3 major groups
Earthworms
-most common
-decomposers
-leave casting(waste product)in soil  produce rich s
Use stiff hairs or bristles to move
Marine Worms -Colorful
-Live in ocean
-Polychaetes covered in bristles “Many bristles”
-Eat mollusks or filter water for food
Leeches
-Parasites that suck blood produces a chemical
that thins blood can be used medically
-Scavengers that eat dead animals
Arthropods and Echinoderms
Four Characteristics Shared by Arthropods
1. Segmented and specialized body
2. Jointed limbs- “athro”(joint) “pod”(foot)
- Body parts bend at joints
3. External Skeleton (Exoskeleton)
4. Well developed nervous system
Segmented
body
Specialized
structures
-head, thorax, and abdomen
Wings, antennae, gills, pincers, claws
Exoskeleton – hard covering of the body
Nervous system
Antennae- feelers that sense touch, taste,
and smell.
Compound eye- several identical light
sensitive units.
Brain/nerve cord
Mandible
- Mouthparts that can pierce objects and chew
Crustaceans
- Have gills, antennae, and mandibles
- Have two compound eyes
Ex: Shrimp, Crab, Lobster
Arachnids
- 2 body parts: Cephalothorax and Abdomen
- 4 pairs of legs, no antennae
- Simple eyes
-spiders,
scorpions, mites, ticks
Insects
- Largest group of arthropods
- Six legs
- 3 main body parts-head, thorax, abdomen
- 2 antennae
Metamorphosis - Change from young to adult
- Organism goes through a complete change
Complete
Metamorphosis - 4 stages: egg, larva, pupa, adult
- No major changes in organism
Incomplete
Metamorphosis - Grows from smaller youth to larger adult
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3 stages: egg ,nymph, adult
Echinoderms
- Means “spiny skinned”
- Radial symmetry
- Simple nervous system
- contains a mouth (nerve ring)
Ex: Sea stars(starfish), Sand Dollars
Endoskeleton - Internal skeleton made of bones or cartilage
Water Vascular - System of canals filled with fluid
- Circulates water throughout the body
System
- Used to move, eat, sense environment, breathe
Types of Echinoderms
Brittle Stars
Basket Stars
-long slim arms
-smaller than sea star
Sea Urchins
Sand Dollars
-round with no arms
-shell-like structure
-use spines and tube feet to move
Sea Lilies
Feather Stars
Sea Cucumbers
-have multiple feathery arms
-no arms and worm-shaped
-soft, leathery body