Transcript Mollusks and Echinoderm PowerPoint

Review the Animal Kingdom
• 4 Major Characteristics?
• Multicellular
• Eukaryotic
• Heterotrophs
• Cells lack cell walls
7 Essential Functions?
• Feeding
• Response
• Respiration
• Movement
• Circulation
• Reproduction
• Excretion
Hard Shells
The Anatomy of a
Sponge
Water flow
Osculum
Central cavity
Pores
Collar Cell
Spicule
Pore cell
Pore
Epidermal cell
Archaeocyte
What makes these animals the simplest of all
animals?
Asymmetrical animals with no true tissues
The first phyla with true tissues is
the
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phyla.
Cnidarian
Whose name literally means
“Stinging cells”
______________________________
Cnidarians have two body forms
Polyp - stationary,
vase-shaped
Medusa - swimming,
cup-shaped
Examples: hydra, coral,
sea anemone
Examples: jellyfish,
portuguese man of war
Ecology of Cnidarians
• A. Source of new drugs/chemicals sunscreen
855
• B. Provide habitats for marine organisms
• C. Source of food for other organisms (like sea
turtles)
• D. Symbiotic relationships with other
organisms
3 Groups of Worms?
• Flatworms
• Roundworms
• Segmented Worms
• What do all 3 groups have in common?
– Bilateral symmetry, cephalization, sexual
reproduction, true organs,
Flatworm adaptation?
• Simplest animals to have bilateral
symmetry and cephalization.
Roundworm Adaptation?
First animals to have a one way digestive
system with mouth and anus
Segmented Worm Adaptation?
First animals to have true circulatory system
Mollusks & Echinoderms
Oysters
Clams
Giant Clams
Zebra Snail
Chinese Mystery Snail
Octopus
Blue Ringed Octopus
Chambered
Nautilus
Caribbean Reef Squid
Giant Squid
Cuttlefish
Mollusks
• Soft-bodied invertebrates
• Have bilateral symmetry, cephalization,
and true organ systems
• Usually have one or two shells with
organs in a fluid filled cavity
• Most live in water
• Diverse - Many different species
• Well developed nervous system in
most
Mollusk Body Plan – 4 parts to
body:
1. Foot- muscular and modified in each group:
used for crawling, burrowing, or may form
tentacles for capturing prey
2. Mantle (covering) – thin layer that covers most
of the body and secretes the shell
3. Shell – made of calcium carbonate – for
protection
4. Visceral mass – area where internal organs are
located.
The Mollusk Body Plan
Section 27-4
Squid
Snail
Shell
Mantle cavity
Foot
Clam
Early
mollusk
Gills
Digestive tract
The Anatomy of a Clam
Stomach
Coelom
Shell
Heart
Nephridium
Adductor muscle
Mouth
Anus
Excurrent
siphon
Adductor
muscle
Incurrent
siphon
Gills
Mantle cavity
Intestine
Mantle cavity
Foot
Classification of Mollusks
• Classified into three common groups
based on shell presence and type and
foot modification
1. Gastropods
2. Bivalves
3. Cephalopods
1. Gastropods
• Largest group of mollusks
• Usually have a single shell
• Use a radula (a tongue-like organ with
rows of teeth) to get food
• Have foot glands that secrete a layer of
mucus for sliding
• Includes snails, conchs, and garden
slugs
2. Bivalves
• Have a hinged, two-part shell
• To open or close their shell they either
contract or relax their muscles
• Includes clams, oysters, and scallops
• Well adapted for water
– Clams can burrow in sand
– Mussels attach themselves to a solid surface
– Scallops escape predators by rapidly opening and
closing their shell
3. Cephalopods
• Most specialized and complex
mollusks.
• Include squid, octopuses, and
chambered nautiluses.
• Have a well developed head
and many tentacles for
capturing prey.
• Closed circulatory system
– Moves blood through the body in
a series of closed vessels like
humans.
• Use jet propulsion to move at
speeds of 6 m/s.
III. Feeding – herbivores, carnivores, filter
feeders, or parasites; some use radula
(tongue with teeth) to feed; filter feeders
suck in water with a siphon
IV. Respiration/Circulation/Excretion –
advanced organ systems - aquatic mollusks
have gills, terrestrial mollusks use
diffusion; open circulatory system in some,
closed in others
V. Response/Movement- well developed
nervous system in most, use mucus to slide,
foot to crawl, jet propulsion in water.
Octopi are most intelligent invertebrates
VI. Reproduction – sexual, internal and
external fertilization, some hermaphrodites
VII. Why are mollusks important?
A. Sources of food for humans and other animals.
B. Biologists can use some mollusks to monitor
water quality in an area because they concentrate
dangerous chemicals in their tissues
C. Some mollusks never seem to develop cancer –
research being done to apply to human health
care
Echinoderms- “SPINY SKIN”
• Characteristics
– Embryonic development most similar to
vertebrates
– Have a thin, bumpy or spiny epidermis
– Radial symmetrical —allowing them to sense
food, predators and other things in the
environment from all directions. Have no head or
brain, but have a nerve ring that surrounds the
mouth
– Have mouth, stomach, intestines
– Feed on a variety of plants and animals
– Also have cells that respond to light and touch
Water-Vascular System
• A characteristic unique to echinoderms
• Allows them to move, exchange CO2 and O2,
capture food, and release wastes
• It is a network of water-filled canals with
thousands of tube feet connected to it.
• Tube feet—hollow, thin walled tubes that
ends in a suction cup.
– As pressure in the tube feet changes the animal is
able to move along by pushing out and pulling in
its tube feet
Types of Echinoderms
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Sea Stars
Brittle Stars
Sea Urchins
Sand Dollars
Sea Cucumbers
Value of Echinoderms
• Feed on dead organisms in the marine
environment
• Help recycle material
• Used for food
• Possible sources of medicine
• Sea stars can help control the
population of other organisms
Arthropods
• Characteristics
– Largest group of animals
– Have jointed appendages which include legs,
antennae, claws and pincers
– Have bilateral symmetry, segmented bodies,
exoskeletons, a body cavity, a digestive system
with two openings and a nervous system
– Most have separate sexes and reproduce sexually
Arthropods
• Body Segments
– Bodies of these animals are divided into segments
similar to segmented worms
– Some have many segments, others have
segments that are fused together to form body
regions
• Exoskeleton
– A hard outer covering that supports and protects
the internal body and provides places for muscle
to attach.
– Doesn’t grow as the animals does, it is shed and
replaced during a process called molting
Insects
• Have three body regions
• Head
– Has a pair of antennae, eyes and a mouth
• Thorax
– Three pairs of legs and one or two pairs of
wings if present are attached here
• Abdomen
– Where reproductive structures are found
Insects
• Have an open circulatory system that carries
digestive food to cells and removes wastes
• Insect blood doesn’t carry O2 instead air
enters and exits through openings called
spiracles found on the abdomen and thorax
• Are the only invertebrate animals that can fly
Metamorphosis
• A series of changes that an insect goes through
• Two types
– Complete
• Includes stages of egg, larva, pupa, and adult
• Ex. Butterflies, bees, flies
– Incomplete
• Includes stages of egg, nymph, adult
• The nymph form molts several times before becoming an
adult
• Ex. Grasshoppers, crickets
Insects & Food
• Feed on a number of things have different
mouth parts to obtain food
• Grasshoppers and ants have large mandibles
for chewing
• Butterflies and honey bees have siphons for
lapping up nectar
• Aphids and mosquitoes have mouth parts
that are adapted for piercing into plants or
other organisms
Insects success
• Insects are extremely successful based
these reasons
– Tough flexible, waterproof exoskeleton
– Ability to fly
– Rapid reproduction cycles
– Small sizes
• Insects have other adaptations that
allow them to be successful
Arachnids
• Have two body regions
– Cephalothorax and an abdomen
• Four pairs of legs and no antennae
• Many are adapted to kill prey with
poison glands, stingers, or fangs
• Some are parasites
Arachnids
• Scorpions
– Have sharp, poison filled stinger at the end of
abdomen.
– Have a well-developed appendages which they
can grab their prey.
• Spiders
– Can’t chew their food, release enzymes into prey
to digest it—then suck the predigest liquid into its
mouth.
– Have book lungs where O2 and CO2 are
exchanged.
Arachnids
• Mites & Ticks
– Most are parasites
– Ticks have specialized mouthparts to
remove blood from the host.
– Ticks often carry disease such as Lyme
disease.
Centipedes & Millipedes
• Have long bodies and many segments,
exoskeleton, jointed legs, antennae and
simple eyes.
• Found in damp environments
• Reproduce sexually
• Make nests for eggs and stay with them until
they hatch.
• Centipedes are predators
• Millipedes feed on decaying plant matter.
Crustaceans
• Have one or two pair of antennae and
mandibles, which are used for crushing
food.
• Most live in water, but some live in
moist environments on land—such as
pill bug.
• Have five pair of legs, first pair of legs
are claws for catching and holding food.
Crustaceans
• Swimmerets are appendages on the
abdomen which help in movement and
are used in reproduction; also force
water over the gills used in O2 and CO2
exchange
• If a crustacean loses an appendage it
can regenerate it
Value of Arthropods
• A source of food
• Agriculture would be impossible without
bees and other insects to pollinate
crops
• Useful chemicals are obtain from some
arthropods
• Important part of ecological community
Controlling Insects
• Not all arthropods are of value some
are pests that carry disease or can
damage crops
Controlling Insects
• Common ways to control insects
– Insecticides, but these also kill non-harmful
insects
– Biological controls
• Types of bacteria, fungi, and viruses can be
used to control insects
• Natural predators being released to kill the
harmful insect
• Some how interfere with reproduction of the
particular insect
Origin of Arthropods
• Some fossils are more than 500 million years
old
• Scientist hypothesized that arthropods
probably evolved from an ancestor of
segmented worms because they have body
segments
• The hard exoskeleton and walking legs
allowed arthropods to be among the first
animals to live successfully on land