INVERTEBRATES
CHAPTER 16
KINGDOM ANIMALIA
Eukaryotic
Heterotrophic
Multicellular
No cell walls
ANIMAL ATTRIBUTES
1. Nutrition
2. Respiration
3. Circulation
4. Support
5. Reproduction
6. Movement
NUTRITION
Heterotrophic- obtain their food from other organisms.
Ingestion
Digestion
Egestion
NUTRITION
As cells digest proteins, they
produce nitrogenous wastes that are expelled through excretion.
These processes are necessary to get needed nutrients and get rid of harmful waste products.
RESPIRATION
Animals exchange gases with their environments.
They have organs that help them get the oxygen they need for
cellular respiration from the environment.
Some get oxygen from air, and some from water.
Animals exhale carbon dioxide as a waste product.
CIRCULATION
All animals transport materials through their bodies to provide nutrients to all their cells.
Some animals have blood or a similar fluid that circulates
nutrients in vessels (closed circulatory system) or bathes internal organs (open cc).
Some organisms, like sponges,
circulate water through their bodies to transport needed substances.
SUPPORT
Because their cells have no cell walls, animals must have another means of support.
This support can be inside or outside the body.
REPRODUCTION
All animals reproduce animals after their own kind.
Most animals reproduce by sexual reproduction.
Many animals also reproduce asexually.
Some reproduce both
sexually and asexually.
MOVEMENT
Animals have some kind of
locomotion- the ability to move through their environments.
Many animals move using
appendages, limbs that protrude from their bodies.
Some animals such as sponges
are capable of moving as larvae
but become sessile as adults.
BODY PLAN
All animals have a body plan.
Animals with no symmetry are said to be asymmetrical.
Animals with bilateral
symmetry can be divided by a plane through their center to form mirror images.
Animals with radial symmetry can be divided by a plane
through their center in several places to form mirror images.
CLASSIFYING ANIMALS
Animals with backbones are called vertebrates.
All vertebrates are classified in one phylum, phylum Chordata.
Animals that do not have backbones are called invertebrates, which make up about 97% of all animals.
ENDOTHERMIC ANIMALS
Body heat comes from metabolism.
Often possess insulating body coverings such as blubber, feathers, fur and hair.
Body temperature is usually not the same as the
surrounding environment.
ECTOTHERMIC ANIMALS
Most animals are ectothermic.
They often have body
temperatures closer to that of the environment.
Use behaviors to regulate body temperature (Ex: sunning
themselves).
ECTOTHERMIC ANIMALS
Some animals escape extreme temperatures by entering a state of torpor.
Their body temperature drops and life processes slow down.
GERM LAYERS
Most animals have germ layers, typically three.
The inner layer, the endoderm, forms the digestive tract.
The mesoderm, the middle layer, forms the muscle and circulatory systems along with others.
The ectoderm forms the outer layer including the outer covering and related systems.
*not shown: flatworms have 2 germ layers, roundworms have 3 germ layers.
The concentration of sensory and nerve cells at one end of an animal is called cephalization.
REPRODUCTION IN ANIMALS
Most animals reproduce sexually.
External fertilization- eggs fertilized outside the
female’s body.
Internal fertilization- eggs fertilized inside the
female’s body.
EMBRYO DEVELOPMENT
Oviparous- “egg birth”: embryos develop outside their mother’s
body within the protective shelter of an egg.
The embryos often use the yolk of the egg for nutrients needed during growth.
Birds, most fish, reptiles, amphibians, and insects.
EMBRYO DEVELOPMENT
Ovoviviparous: embryos develop inside their
mother’s body, with no placental connection to her.
Some fish, reptiles, amphibians, and insects.
EMBRYO DEVELOPMENT
Viviparous- “live birth”: Developing embryos draw their nutrients from their mother’s body.
Most mammals and some fish, amphibians, reptiles, and a few insects.
ANIMAL BEHAVIOR
Seasonal cycles
Circadian rhythms
Learned behaviors
Instincts
seasonal
Circadian (day/night)
learned behavior
instinct
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CLASSIFYING SPONGES
Kingdom Animalia, Phylum Porifera
Invertebrates
no germ layers
Asymmetric
Sessile (nonmotile)
~10,000 species
WHAT MAKES SPONGES ANIMALS?
Eukaryotic cells
Multicellular
Heterotrophic
Though sessile, sponges move their environment through them.
Motile larvae sponge larva
SPONGE STRUCTURE
Tubes with only one open end.
Walls of body supported by spicules and/or spongin
Spongin- tough, flexible
Spicules- hard, pointy
SPONGE NUTRITION
Water flows in through pores, bringing food and nutrients with it.
Waste products are ejected into the current through its osculum.
SPONGE DIGESTION
Flagellated cells called collar cells line the inside of the
sponge.
Collar cells engulf food
particles through phagocytosis and partially digest it.
Digestion inside cells instead of a digestive system is called intracellular digestion.
SPONGE- ASEXUAL REPRODUCTION
Sponges reproduce both sexually and
asexually. gemmule
SPONGE- SEXUAL REPRODUCTION
Sponges are hermaphroditic, having both male and female reproductive organs.
CLASSIFYING CNIDARIANS
Kingdom Animalia, phylum Cnidaria
Two germ layers
Radial symmetry
CNIDARIAN STRUCTURE
Nerve net
Hydrostatic skeleton
Corals excrete calcium carbonate exoskeletons
Polyp form and Medusa form
medusa
polyp
POLYPS
Basal disc- attaches to hard surfaces
Tentacles- pull food into its mouth
Gastrovascular cavity- digestion and food circulation
Cnidocytes- stinging cells
Nematocyst- barb covered with venom
Study this figure for the test! →
MEDUSAS
Umbrella-shaped free-swimming form.
Glides through the water by pumping its body.
Many cnidarians spend part of their lives in both polyp and medusa forms.
Some exist only in polyp form (corals and sea anemones).
Others have only a medusa stage (some jellyfish).
CNIDARIAN REPRODUCTION
Can reproduce asexually by dividing themselves in half or through budding.
Reproduce most often through sexual reproduction.
Unlike hermaphroditic sponges, an individual cnidarian is
typically either male or female.
ROLE OF SPONGES AND CNIDARIANS
Larvae make up plankton, the
foundation of the marine food chain.
Most sponges are filter feeders, eating detritus.
Cnidarians are usually carnivorous.
Some sponges and cnidarians are parasitic.
ROLE OF SPONGES AND CNIDARIANS
Sponges and corals form mutualistic symbiotic
relationships with algae; algae are vital for coral reefs.
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CLASSIFYING WORMS
Three different kinds of worms:
Flatworms
Roundworms
Segmented worms
WORM CHARACTERISTICS
Soft, long bodies
Three germ layers
Bilateral symmetry
Few to no appendages
Free-living worms tend to be more complex than parasitic ones.
bilateral symmetry three germ layers
FLATWORMS
Phylum Platyhelminthes.
Include tapeworms, flukes,
planarians, and marine flatworms.
Most flatworms are parasites.
Some, like the planarian, are free- living inhabitants of lakes, streams, and moist terrestrial habitats.
tapeworm
planarian
marine flatworm
ROUNDWORMS
Also known as nematodes.
Mostly tiny, round worms less than an inch long.
Found everywhere- water, soil, even your body.
Ascaris is a parasitic
roundworm that can reach a foot long.
Ascaris
root knot nematode
SEGMENTED WORMS
Also known as annelids.
An earthworm is the most familiar example of a segmented worm.
Have a bumpy body, called a segmented body plan.
The Giant Gippsland earthworm can grow to be a yard long.
earthworm
Giant Gippsland earthworm
SEGMENTED WORMS- LEECHES
Australian Land Leeches
Kinabalu Giant Red Leech
Medicinal Leech
SEGMENTED WORMS
Other segmented worms include clam worms and feather worms.
Clam Worm
Feather Worms
DIGESTIVE SYSTEM
Forms from the endoderm.
Extracellular digestion.
Some parasitic worms absorb nutrition directly from the host’s intestines.
Free-living worms eat detritus, fungi, protozoans, and algae.
NERVOUS SYSTEM
The ectoderm forms the outer
layer of the worm, which typically has the sensory organs.
Sensory organs feed information from the environment to the
nervous system.
The nervous system is made up of bundles of nerve cells called ganglia.
WORM SKIN
In flatworms, the tegument is part of the living cells of the outer layer of the worm.
Most segmented worms and roundworms have a nonliving layer of cells called the cuticle.
tegument
cuticle
CIRCULATORY SYSTEM- SEGMENTED WORMS
Forms from the mesoderm.
Only segmented worms have a closed circulatory system.
CIRCULATORY SYSTEM- FLATWORMS AND ROUNDWORMS
No circulatory system
No body cavity (coelom)
Roundworms transport nutrients with the fluid in their “body
cavity” called a pseudocoelom.
Flatworms use diffusion to
spread nutrients through their body.
roundworms
flatworms
Important for the test! →
RESPIRATORY AND EXCRETORY SYSTEMS
Most worms breathe through their skin.
Some flatworms and
segmented worms remove
nitrogenous wastes with flame cells.
Roundworms remove
nitrogenous wastes with
structures called excretory cells.
Flame cell
Excretory cell
REPRODUCTION IN WORMS
Reproduce sexually, although some also reproduce asexually.
Flatworms and segmented worms are generally
hermaphroditic and cross-
fertilize with other individuals.
REPRODUCTION IN WORMS
Worms that live in a watery environment have eggs that
hatch to release a plankton-like larva called a trochophore.
Parasitic worms typically release their eggs in the feces of their
hosts.
tapeworm
trochophore
PARASITIC WORMS
All three types of worms can be parasitic.
Fewer parasitic segmented worms than roundworms or flatworms.
Fewer sensory organs.
Not as capable of locomotion.
Ability to avoid the host’s immune system.
PARASITIC WORM LIFE CYCLE
Life cycle involves at least two hosts.
The adult parasite matures and sexually reproduces in the definitive host.
After the parasite’s eggs pass out of the definitive host, the larvae enter an intermediate host and undergo one or more stages of development.
The intermediate host is then eaten by the definitive host, completing the parasite’s life cycle.
MEDICAL USES OF PARASITIC WORMS
People with overactive immune
systems can be deliberately infected with certain types of parasitic worms to decrease the body’s immune
response.
Leeches can be used on skin graft patients to keep the blood from
clotting, allowing the blood vessels of the two pieces of skin to grow
together.
WORMS AS DECOMPOSERS
Some worms, especially earthworms, fill an important need in the
environment as decomposers.
Earthworms eat decaying organic matter and expel their wastes as castings, which enrich the soil.
Earthworm burrows allow oxygen and water to filter down into the ground, enabling plants to send their roots deeper.
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CLASSIFYING MOLLUSKS
Phylum Mollusca in Kingdom Animalia.
Include squids, slugs,
oysters, octopuses, clams, cuttlefish, nautiluses, and snails.
Second largest phylum in
Kingdom Animalia.
BIVALVES
Include clams, oysters, mussels, and scallops.
Have two shells connected by a hinge.
The mantle is a sheath of tissue that wraps around the organs.
A fleshy, muscular foot helps clams move around.
GASTROPODS
Includes slugs and snails.
Includes some terrestrial species.
Have a foot that is found below their visceral mass, the part of a mollusk’s
body that contains its heart and digestive organs.
CEPHALOPODS
Include cuttlefish, octopus, squid, and nautilus.
Have feet that are divided into tentacles, which are used to catch food.
Can be highly intelligent.
Pigment-bearing cells called chromatophores allow them to change color for camouflage and communication.
MOLLUSK CHARACTERISTICS
Three germ layers
Cephalization (most)
Bilateral symmetry (most)
All have digestive, circulatory,
nervous, and respiratory systems.
MOLLUSK STRUCTURE
Nervous system may consist of ganglia or brain similar to vertebrates (cephalopods).
Circulatory system may be open (bivalves and
gastropods) or closed (cephalopods).
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MOLLUSK STRUCTURE
Underwater mollusks breathe using gills.
They circulate water from their environment through two tubes called siphons.
One siphon brings water in and the other allows water to leave.
They allow a mollusk to move quickly to avoid a predator.
MOLLUSK STRUCTURE
Gastropods and most
cephalopods have both a mouth and a radula.
A radula is a specialized rasping feeding structure for scraping up food and pulling it into the mouth.
MOLLUSK REPRODUCTION
Most reproduce sexually.
Simpler mollusks use external fertilization
More complex mollusks such as
cephalopods use internal fertilization.
Some species such as snails are hermaphrodites.
Aquatic larvae an important part of plankton community.
ROLE OF MOLLUSKS
Most are aquatic.
Can be carnivores, herbivores, and scavengers.
They eat algae, detritus, and various prey animals.
Mollusks play a role in a variety of ecosystems, such as the coral reef community.
Humans use for food.
Medical research.
CLASSIFYING ECHINODERMS
Phylum Echinodermata
Sea urchins, sea stars (starfish), brittle stars, sea cucumbers, and sea lilies.
Can be found in all ocean zones, though most live in the deep
ocean zones and intertidal zones.
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ECHINODERM CHARACTERISTICS
Three germ layers
Radial symmetry
Most have an endoskeleton
made of plates called ossicles.
ECHINODERM STRUCTURE
Water-vascular system- a series of canals and tubes used for
circulating nutrients, moving, and capturing food.
Water enters through the sieve- like madreporite.
From there it travels through a series of canals to hundreds of hollow tube feet.
ECHINODERM STRUCTURE
Echinoderms have all of the body systems associated with animals.
Respiration through tube feet or gills.
Closed digestive system with
mouth on lower surface and anus on upper surface.
Nerve net like a cnidarian.
Open circulatory system.
ECHINODERM REGENERATION
Able to regenerate lost limbs.
Can completely
regenerate from one limb if part of the
central disc is present.
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ECHINODERM REPRODUCTION
Reproduce both sexually and asexually.
Usually reproduce sexually when male and female echinoderms mate, though some are hermaphroditic.
Eggs are fertilized through external fertilization, with some species
guarding or brooding their fertilized eggs.
Larvae exhibit bilateral symmetry.
ROLE OF ECHINODERMS
All are marine.
Variety of roles in the environment:
algae grazers, detritovores, scavengers, and predators.
Some find shelter and food in the coral reef community.
Shells are used as a source of calcium carbonate (limestone) to fertilize farm fields.
ECHINODERMS AS FOOD
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