So Green: Invertebrates-hndout

1.Phylum Porifera
Every one of you might be familiar with Sponge Bob right? Well the author refers to this asymmetrical phylum of vertebrates known as the sponge.
It is called the simplest form of animal life because although they are multicellular organisms which contain several different cell types
they are lacking true tissue.
They are aquatic animals (live in water) and do not move around (sessile animal) with lots of pores (holes) all over their bodies. They are all filter feeders (animals that obtain nutrients by filtering suspended particles or small organisms from water). Most sponges have spikes which support it, keeping it upright in the water and defending itself from the predators.

Examples: tube sponge, glass sponge, sea sponge

picture of tube sponge:

2.Phylum Cnidaria
Members of this phylum have radial symmetry, they are aquatic animals. Most of them have tentacles arranged in a ring around their mouth with nematocysts (stinging cells which can release toxic or sticky substances to paralyze the prey). It has a gastrovascular cavity for digestion with one single opening to this cavity that functions as both mouth and anus. They have two different body plans:
1).Polyp (sessile, reproduce by budding)
2).Medusa (motile, sexual reproduction)
hydraSome species of cnidarians live in a colony (a group of many individual animals living together), one of them is stony coral. Both sea anemones and coral occurs only as polyps in the marine world. Other species such as hydra prefer to live soliter (alone) in a fresh water habitat.
Examples : jellyfish, hydra, sea anemones, coral

hydra:

sea anemone:

picture of stony coral :

3. Phylum Molusca
They are invertebrates with soft bodies that are often protected by a hard outer shell. A mollusk has a thin layer of tissue called a mantle that covers its internal organs, which in many mollusks produce a hard shell. It has a digestive system with two opening. Three major classes of mollusca are
· Class Gastropoda (some have shells and move with a muscular foot; ex: snail & sea slug)

· Class Bivalvia (have two shells held together; filter feeder; ex: oyster, clams, scallop)

· Class Cephalopoda (have tentacles→ modification from muscular foot; no shell except nautiluses; ex: octopuses & squid)

Vermes: worm like
The simplest animal with a brain which are sensitive to light, touch, and vibration from the environment. For example, if an earth worm on the surface of the ground gets too much light or senses vibration of a foot step, the worm will quickly return underground to avoid it.
4.Phylum
Platyhelminthes
They are known as flatworms because they are flat like a ribbon and as soft as jelly. They have bilateral symmetry. Many flatworm are parasites in vertebrates bodies (ex: tape worm and flukes), while some of them (ex: planarian) are free living in the aquatic or damp soil habitat.
planarian:

tapeworm:

5.Phylum
Nematoda
Known as a round worm it has a cylindrical body. They look like tiny strands of cooked spaghetti, which are pointed at each end. It has a digestive system that is like a tube, open at both ends (starts from mouth and ends in anus).
Some of them are parasites (ie: Ascaris lumbricoides and hook worms) or free living animals.

6.Phylum Annelida
Known as segmented worms which have bodies made of many linked sections known as segments. Earth worms and leeches are included in this phylum. They are hermaphrodites (have male and female reproductive organs in one organism) but they cross-fertilize. Earth worms respirate through their moist skin.

7. Phylum Arthropoda
Athopod means jointed legs. All arthropods have an exoskeleton or outer skeleton (have skeleton outside the body) which protects them and helps prevent water evaporation. They have a segmented body and jointed attachment called appendages (wings, mouth parts, and legs). They have bilateral symmetry, and open circulatory system with two openings.
Metamorphosis: The body form changes from embryo to adults. It increase in size, reorganizes tissue, remodels its body parts.
Complete: egg→larva→pupa→adult

Incomplete: egg→nymph→adult

insecta:

compound eye:

arachnid:

crustaceae:

myriapoda:

8. Phylum Echinodermata

They are invertebrates with an endoskeleton and water vascular system (a network of internal canals to pump water to the different parts of their body for movement, feeding and gas exchange). The skin of most echinoderms is covered by spines. They have bilateral symmetry as larvae and pentaradial symmetry as adults (body part usually in multiples of five). Adults have no head or brain and they live in salt water. They have tube feet for movement, the end of them are sticky. When filled with water they act like small sticky suction cups. The stickiness and suction enable the tube feet to grip the surface beneath the echinoderm so it can move along slowly and can help it to capture food. Respiration of echinoderm is done using skin gills.
sea urchin
star fishExamples: star fish, sea urchin, sea cucumber, sand dollars