Animal KingdomInvertebrates

Animals without a backbone

All organisms in this kingdom have these common characteristics:

•Multicellular •Eukaryotes•No cell wall- unlike fungi, plants, bacteria•Heterotrophs– consumers•Have Specialized Cells- unlike protists

Asymmetry – no symmetry

Radial symmetry - can cut in equal halves-more than one way

Bilateral symmetry – allows for development of brain region in a central location (head)

Body Plans

Asymmetrical body

Radial Symmetry

Bilateral Symmetry

Bilateral Symmetry

•Has a head (dorsal) end and a Tail (caudal) end.•Has a right and left side.•Has a front (anterior) and a Back (posterior) side.

Development of OrganismsDevelop from a single cell, the zygote

Mitosis forms new cell in a process called cleavage

A hollow ball of cells are formed called a blastula

Gastrulation is the folding in of the blastula to form two layers

These two layers are the ectoderm and theEndoderm.

Ectoderm develops into skin and nervous tissueEndoderm develops into the lining of the digestive tract and organs associated with digestionIn some animals the gastrula forms a mesodermMesoderm is the third layer and develops into muscles, circulatory, excretory, and respiratory systems

Development

Acoelom- do not have a body cavity, organs are imbedded in tissues

Pseudocoelom -(partial) a body cavity partly lined with mesoderm

Coelom- a body cavity that provides space for the development of internal organs (something for muscles to push against to move)

Body Cavities

Phylum Porifera

PHYLUM: PORIFERAPore-bearing animalssponges

Sessile - do not moveAsymmetricalNo tissue (Only organized cells – 2 cell layers)No mouthHermaphrodite

Porifera

Characteristics:

Body plan: 2 cell layers skeleton of spicules (spines)

Sexual – release sperm into water (external fertilization very common in aquatic animals)

Hermaphroditism – sponges have sperm AND eggs to increase the odds of reproduction

Offspring can swim to a new location

Asexual fragmentation also possible

PHYLUM: CnidariansStinging cell animalsJellyfish, coral, sea anemonea

Evolution of Radial Symmetry

Extends tentacles equally in all directions (increase food uptake)

Characteristics:•Stinging cells•3 cell layers•Mouth, gut for digestion•Nerve net throughout body•2 body forms

Reproduces sexually and asexually

Skeleton-none present, but dead coral remains are calcium carbonate

PHTLUM: Platyhelminthes The flatworms Planeria, tapeworms, flukes

Characteristics:

No coelom – Why? Many are parasitic

O2 and sugar are absorbed in host’s intestine

Bilateral symmetry

Reproduction-most are hermaphrodites

Tapeworm

http://www.bu.edu/lernet/GK12/eric/flatworm.jpg

PHYLUM: Nematoda Roundworms hookworm, heartworms

Characteristics:

•Smooth, non-segmented body

•Pseudocoelom (moves more)

•Can burrow through skin (walking around barefoot)

•Also enters through contaminated food

•Bilateral symmetry

•Complete digestive system with mouth and anus

•Sexual reproduction. Sexes seperate

•Oxygen enters by diffusion

Hookworms, Pinworms, Tapeworms that were removed from a Brazilian boy treated on a Rockefeller foundation mission (early 1900’s)

These parasites still affect people all over the globe.

RoundwormsDirofilaria is a roundworm that causes heartworm disease in dogs

http://www.answers.com/topic/hookworms-jpg

PHYLUM: Annelid Segmented Worms earthworms, leeches, sea slugs

Characteristics:•Bilateral symmetry•Full Coelom (full range of motion, complex organs inside)•Complete digestion system•Most are hermaphrodites with sexual reproduction

•Gets O2 directly from moist skin

•closed circulatory system with 5 hearts to deliver

Food – blood (leeches), or dirt (earthworms)

Swallow dirt, filter out food

Loosen soil, helps to aerate soil for plants

Also fertilizes plants with castings (poop)

PHYLUM:Mollusks Head-footed animalsClams, snails, squid, oysters, octopus

Characteristics:•Bilateral symmetry

•Getting food – filter feeders (clams), grazers (snails), predators (slugs)

•Getting O2 – gills in aquatic mollusks, primitive lung in snails

•Open or closed circulatory system

PHYLUM:Arthropods Jointed legged animals Spiders, insects, crabs, millipeds

Four main classes within this HUGE phylum:1. Arachnids2. Crustaceans3. Centipedes / millipedes4. Insects

PHYLUM: Echinoderm Spiny Skinned AnimalStar fish, sea urchin, sea cucumber

Characteristics:•Radial symmetry•Mouth on ventral side of body•Marine•Reproduction: sexes separate, external, forms pelagic (free-floating) larvae•Water vascular system with tube-feet •Can regenerate lost body parts

http://www.starfish.ch/Fotos/echinoderms-Stachelhauter/seacucumbers-Seewalzen/Thelenota-ananas4.jpg