InvertebratesDo not have a backbone or vertebral columnRange in size from microscopic dust mites to

giant squidsInclude groups of sea stars, worms, jellyfish,

and insects95% of all animals are invertebrates

Body SymmetryRadial Symmetry- any number of imaginary

planes can be drawn through the center, each dividing the body into equal halves

Bilateral Symmetry- can only draw one imaginary plane and it divides the body into two equal halves

Asymmetrical Symmetry- cannot put any lines to divide it evenly

Cephalization- is the concentration of sense organs and nerve cells at the front end of the body. Usually animals that have bilateral symmetry exhibit cephalization

SpongesSponges are in the phylum Porifera means

“pore- bearing”Live their entire adult life attached to one

place.They have nothing resembling a mouth, gut

and they have no tissues or organ systems. Asymmetrical they have no front or back have no standard form

CnidariansSoft bodied carnivorous animals that have

stringing tentacles arranged in circles around their mouths

They are the simplest animals to have body symmetry and specialized tissue

They have a life cycle that includes two different looking stages: a polyp and a medusa

WormsThey come in several different types; flat,

round and segmentedBody cavities there are three kinds

acoelomate (no body cavity), pseudcoelomate (fake body cavity), coelomate (real body cavity lined with tissue)

Most worms have exhibited cephalization at least enough to call a head

Some worms can cause diseases in humans

MollusksAre soft bodied animals that usually have an

internal or external shellInclude snails, slugs, clams, octopi, and

squidsGroups of mollusks

Gastropods are shell-less or single-shelled mollusks that move by using a muscular foot located on the ventral side

Bivalves have two shells that are held together by one or two powerful muscles

Cephalopods are typically soft-bodied mollusks in which the head is attached to a single foot, the foot is divided into tentacles or arms

Gastropod

Bivalve

Cephalopods

Bivalves

ArthropodsHave segmented bodies, a tough exoskeleton,

and jointed appendagesThe exoskeleton is made up of chitin that is

made from protein and carbohydratesAppendages are things like legs and antennae

that extend from the bodyWhen they out grow their exoskeleton they go

through a period of molting or sheding of their exoskeleton

There are 4 subphylum of arthropods or groups

Classification of arthropodsThey are classified based on the number and

structure of their body segments and appendages- particullarly their mouthparts

The three major groups of arthropods are crustaceans, spiders and their relatives, and insects and their relatives

CrustaceansMembers of this group are things like crabs,

shrimp, lobsters, crayfish, and barnaclesTypically have two pairs of antennae, two of

three body sections, and chewing mouthparts called mandibles

The body sections Cephalothorax- it is formed by fusion of the head

with the thorax. Which lies just behind the head and houses most of the internal organs.

Abdomen- is the posterior part of the bodyCarapace- is the part of the exoskeleton that

covers the cephalothorax

Spiders and Their RelativesThese include all spiders, horseshoe crabs,

mites, ticks, and scorpionsThey have mouthparts called chelicerae and two

body sections, and nearly all have four pairs of walking legs

They have a cephalothorax, and an abdomen. They have the same kind of body structure as crustaceans, but they lack antennae.

They have two pairs of appendages attached near the mouth. One pair is called chelicerae contain fangs and are used to stab and paralyze prey.

The other pair is called padipalps they are longer and usually modified to grab prey

EchinodermsEchinoderms are characterized by spiny skin,

an internal skeleton, a water vascular system, and suction-cuplike structures called tube feet.

Most adult echinoderms exhibit five-parts radial symmetry. They have appendages that occur in multiples of five

Classes of echinoderms include sea urchins, sand dollars, brittle stars, sea cucumbers, sea stars, sea lilies and feather stars

Insects and Their RelativesUniramians are centipedes, millipedes, and insects.

They have jaws, one pair of antennae, and unbranched appendages.

Insects have three-part bodies (head, thorax, and abdomen) three pairs of legs are attached to the thorax and most are adapted for flight

There are two types of metamorphosis incomplete and complete

Incomplete they have an adult and an immature stage

Complete they have the same stages but within those stages they completely change from one thing to another