Invertebrate Animals
BY: ANTHONY MARCH
Animals Characteristics
1.
Eukaryotic
2.
Multicellular
3.
Have no cell walls
4.
cell membranes made of fatty acids
5.
Reproduce either sexually or asexually
Symmetry
Symmetry - the quality of being made up of exactly similar parts facing each other
Asymmetrical - having parts that fail to correspond to one another in shape, size, or
arrangement; lacking symmetry (Ex: Fiddler crab)
2 types of symmetry –
1.
Bilateral symmetry (Ex: Humans)
2.
Radial symmetry (Ex: Sea urchins)
Invertebrates
An animal lacking a backbone
Sponges
Definition – a primitive sedentary aquatic invertebrate with a soft porous body that is typically
supported by a framework of fibers or calcareous or glassy spicules. Sponges draw in a current of
water to extract nutrients and oxygen
5,000 species of sponges
Filter feeders - are animals that feed by straining suspended matter and food particles from
water, typically by passing the water over a specialized filtering structure. (Ex: sponges)
Sponges live in sea water and freshwater
Sponges are important to their ecosystem because they serve as protection to fish, and they
provide the animals that live inside of them with a rich food supply that they get from the water
circulating through them.
Sponges body Forms
Sponges are supported by different things including calcareous laminae, organic filaments, and
siliceous and calcareous spicules.
Spongin - the horny or fibrous substance found in the skeleton of many sponges.
Sponges are made up of cells, spicules, and spongin.
Sponges body parts:
Spicule - Small pointed structure serving as a skeletal element in various marine and freshwater
invertebrates e.g. sponges and corals
Ostium - One of the small openings in a sponge's body through which water enters
Filter Chamber - Specialized structure that allows fluid feeders to obtain more nutrients; increases
absorption area
Osculum - A large opening on a sponge through which filtered water is expelled
Collar Cell - Any of the flagellated cells in sponges having a collar of cytoplasm around the flagellum
Tubular - Having hollow tubes (as for the passage of fluids)
Cnidarians
Definition - an aquatic invertebrate animal of the phylum Cnidaria
Hydra – They live in unpolluted fresh-water ponds, lakes, and streams in the temperate and
tropical regions. They mainly feed on small aquatic invertebrates such as Daphnia and Cyclops.
They capture their prey by extending their tentacles, injecting their prey with nematocysts,
wrapping the tentacles around their prey and pulling it into their mouth.
Jellyfish – They live in oceans. Since jellyfish are carnivorous, they mainly feed on plankton,
crustaceans, fish eggs, small fish and other jellyfish. They deliver an electric shock to their prey,
wrap their tentacles around it and pull it into their mouth.
Corals – They live in shallow tropical water. They stay alive by receiving nutrients from algae,
capturing particles such as plankton, and taking up dissolved substances from the water. The
tentacles of the coral kill or immobilize the prey and pull it in to be eater.
Anemones – They live at the bottom of the oceans. They feed on smaller organism by
killing/immobilizing them and pulling them into their mouth with their tentacles
Cnidarians Body Forms
Polyp Stage – cylindrical in shape and elongated at the axis of the vase-shaped body. Body could
be roughly compared to a sac. Body parts/anatomy include tentacles, a mouth/anus,
gastrovascular cavity, mesoglea, ectoderm/endoderm.
Medusa Stage – Symmetrical body and looks like an umbrella. Body parts/anatomy include
tentacles, a mouth/anus, gastrovascular cavity, mesoglea, ectoderm/endoderm.
Flatworms
Definition - a worm of a phylum that includes the planarians together with the parasitic flukes
and tapeworms. They are distinguished by having a simple flattened body that lacks blood
vessels, and a digestive tract that, if present, has a single opening
1.
Planarians (Turbellaria) – Mostly feed on small organisms or dead bodies of organisms. Most
live in freshwater under rocks, and on plant materials.
2.
Flukes (Trematoda) – Flukes are parasitic so they live off the host that they are attached to
on the inside of their host or on the outside.
3.
Tapeworms (Cestoda) – Tapeworms are parasitic. Their head attaches to the intestinal walls
of Humans and animals. This way they live and feed off their host.
Tapeworms
Definition - a parasitic flatworm, the adult of which lives in the intestine of humans and other
vertebrates. It has a long ribbon-like body with many segments that can become independent,
and a small head bearing hooks and suckers.
Tapeworms grow and survive by taking nutrients directly from their hosts. They do this because
they are parasitic.
Parasitism – Parasitism is a non-mutual (one benefits while other is harmed) symbiotic
relationship between two organisms where one organism (Parasite) benefits at the expense of
the other (host)
Tapeworms live on the intestinal walls of its host (humans, dogs, cats, etc..) and they feed off
their hosts to stay alive.
Roundworms
Definition - a nematode, esp. a parasitic one found in the intestines of mammals.
1.
have a thick cuticle that covers their bodies and is shed in order to allow for growth
2.
They have muscles located between the cuticle and the pseudocoel that push on both the
cuticle and the pseudocoel and create a kind of hydrostatic skeleton
3.
muscle cells branch toward the nerve cells
4.
mouth usually has 16 protruding sensory organs and sometimes displays piercing
structures called “stylets.”
They survive by alternating between hosts and regions in their hosts' bodies. This is non-mutual
symbiotic relationship that they have where they benefit from their host.
A hookworm is a type of roundworm. Hookworms live in the small intestines of its host and it
feeds of its host.
Mollusk
Definition - an invertebrate of a large phylum that includes snails, slugs, mussels, and octopuses. They
have a soft, unsegmented body and live in aquatic or damp habitats, and most kinds have an external
calcareous shell
Mantle – excrete calcium carbonate to create the shell of the animal.
Gills – to breath
Characteristics - contain a soft body containing a visceral mass, a foot and a mantle, bilateral
symmetry, have a mantle cavity that functions to excrete gases and waste
Anatomy/Body Structure – Some of the organisms have hard shell as protection. Anatomy includes
gills, complete digestive systems, 3-5 cell layers, nerve system, and for some a shell.
Type of Mollusks
1.
Snail – Has a single spiral shell into which the whole body can be withdrawn. They live in
diverse climates such as deserts and mountain areas and even in marshes. What they eat
depends on the type of snail they are and where they are and what’s in their environment
2.
Slug – A tough-skinned terrestrial mollusk that typically lacks a shell and secretes a film of
mucus for protection. They live in damp areas, soil litter, under foliage of plants. Ripe
strawberries are a favorite meal for slugs. In addition to the strawberries, they like many
kinds of plants, including corn, lettuce, beans, and flowers of all kinds.
3.
Squid - An elongated, fast-swimming cephalopod mollusk with ten arms (technically, eight
arms and two long tentacles), typically able to change color. They live in all of the oceans of
the world. A squid's diet consists of shrimp, plankton, crabs, and small plants. Squid also eat
small fish. Larger squid will sometimes feed on smaller squid, as well
Segmented Worms (Annelids)
1.
Earthworm –They live in the soil, trees, under rocks and on banks of streams. They form burrows
in wet soil and may go up to six feet deep into the soil. They eat dirt. Their nutrition comes from
things in the dirt such as decaying roots and leaves.
2.
Marine sand worm – They live in mud or sand in coastal areas. Different types of marine worms
eat different things. The filter feeding worms eat bacteria and phytoplankton while the burrowing
one eat pieces of plants and animals in the sand. The predatory worms eat shrimp, sea urchins,
and fish.
3.
Leeches – They live in freshwater surroundings, but some species can survive in marine and
terrestrial environments. They feed on tubificid worms and on the flesh or fluids of other animals
They are made up of ring-like segments called annuli. These segments are covered in small bristles.
There body is a long slippery structure. Their anatomy includes a complete digestion system, a
mouth/anus, anterior connection of nerves, single ventral nerve cord with ganglia, setae for
locomotion with muscular contractions, non skeleton, seminal vesicles/receptacles.
Arthropods
Definition - an invertebrate animal of the large phylum Arthropoda, such as an insect, spider, or
crustacean.
Appendages - an external body part that protrudes from an organisms body
Exoskeleton - a rigid external covering for the body in some invertebrate animals, esp.
arthropods, providing both support and protection.
Their anatomy includes a complete digestive system with side-to-side jaws, Developed brain,
ventral nerve cord, many specialized sensory organs, jointed legs, exoskeleton.
An example of arthropods would be insects. Insects mainly live in the soil, caves and on the
mountains. Some of them eat other insects. Some of them eat blood (like
mosquitoes). Nectar from plants is also a popular food. And many insects (like cockroaches or
ants) will eat food that falls on the floor like a cookie.
Insects
3 regions of insects include the head, the thorax, and the abdomen
Open circulatory system - The open circulatory system is common to molluscs and arthropods.
Open circulatory systems (evolved in crustaceans, insects, mollusks and other invertebrates)
pump blood into a hemocoel with the blood diffusing back to the circulatory system between
cells. Blood is pumped by a heart into the body cavities, where tissues are surrounded by the
blood.
Fly – They are commonly found in homes, restaurants and other facilities where food is
processed since they live off bacteria ad germs.
Ant – They live on the ground or on the soil surface. They live in colonies; where you spot a small
mound of dirt on the ground. Ants like sweets and they more often than not swarm around
sweets or sugar but rarely crowd around salty food.
Ladybug - They reside where insect pest populations are high. Such as in crop fields, gardens,
and in the canopies of trees. They eat aphids which are insects that suck the sap out of plants.
An insects anatomy includes - a complete digestive system with side-to-side jaws, Developed
brain, ventral nerve cord, many specialized sensory organs, jointed legs, exoskeleton, and wings
Metamorphosis
Complete Metamorphosis
insect development in which egg, larval,
pupal, and adult stages occur
Incomplete Metamorphosis
- A life style of certain insects
characterized by the absence of a pupal
stage between the immature and adult
stages.
Crustaceans
Defined - an arthropod of the large, mainly aquatic group Crustacea, such as a crab, lobster,
shrimp, or barnacle.
1.
Lobster – They live in all of the oceans. The lobsters live and eat at the bottom of the oceans
floor. They eat small fish, worms, invertebrates, protozoa, sea plants, and even other
crustaceans
2.
Crabs – They live in the ocean or on river banks, lakes, rocks, and in deep holes in the sand.
Crabs are small sea creatures with eight legs and two claws that they use to crack open the
shells of marine snails and eat them.
3.
Spiders – They live in almost every habitat on earth,but in oceans and Antarctica.mostly
common in gardens. The majority of spiders feed on insects but the larger species will also
eat other small animals such as millipedes and wood lice (slaters), small lizards and frogs,
and even small birds in the case of tarantulas and the largest of the golden orb weavers.
4.
Harvestman – The live in fields and forests. They feed on insects and other small creatures.
Anatomy - includes a complete digestive system with side-to-side jaws, Developed brain,
ventral nerve cord, many specialized sensory organs, jointed legs, exoskeleton.
Echinoderms
- a marine invertebrate of the phylum Echinodermata, such as a starfish, sea urchin, or sea cucumber.
Star fish – Starfish occur in all of the Earth's oceans. Almost anything that moves slower than they do
– which is a lot of sea creatures. Sea stars are successful scavengers and predators. Some attack
mollusks, like mussels and oysters, which don't move, and some feed on dead fish or other carrion
Sea urchin – They live on the floor of the oceans or bays. They can also be found in the rocks of the
shallows. They can also attach themselves to coral. Their diet includes things such as mussels, small
fish, algae, and sponges
Brittle stars – They live under rocks on the floor of the oceans or bays. Different species of brittle
stars have any one of 3 different feeding habits. Some are suspension feeders who capture particles
of algae etc. from the water floating by them. Some are bottom feeders collecting from the ocean
bottom. Then there are some that are predatory using their arms to capture small sea animals and
mollusks.
Anatomy includes stomach, radial nerves, tube feet, digestive glands, gills, and a spine
Water-Vascular system
Definition: a network of water vessels in the body, the tube feet being operated by hydraulic pressure
within the vessels