Animal Kingdom Invertebrates Animals without a backbone All

Animal Kingdom Invertebrates 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

Body Plans 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)

Asymmetrical body

Radial Symmetry

Bilateral Symmetry

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

Development of Organisms Develop 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 the Endoderm.

Development Ectoderm develops into skin and nervous tissue Endoderm develops into the lining of the digestive tract and organs associated with digestion In some animals the gastrula forms a mesoderm Mesoderm is the third layer and develops into muscles, circulatory, excretory, and respiratory systems

Body Cavities 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)

�PHYLUM: PORIFERA �Pore-bearing animals �sponges Phylum Porifera

Porifera Characteristics: Sessile - do not move Asymmetrical No tissue (Only organized cells – 2 cell layers) No mouth Hermaphrodite

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: Cnidarians Stinging cell animals Jellyfish, 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 O 2 and sugar are absorbed in host’s intestine Bilateral symmetry Reproduction-most are hermaphrodites

Tapeworm

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.

Roundworms Dirofilaria is a roundworm that causes heartworm disease in dogs

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 O 2 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 animals Clams, snails, squid, oysters, octopus

Characteristics: • Bilateral symmetry • Getting food – filter feeders (clams), grazers (snails), predators (slugs) • Getting O 2 – 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. Arachnids 2. Crustaceans 3. Centipedes / millipedes 4. Insects

PHYLUM: Echinoderm Spiny Skinned Animal Star 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