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
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
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 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.
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 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: PORIFERA Pore-bearing animals sponges
Sessile - do not move Asymmetrical No tissue (Only organized cells – 2 cell layers) No mouth Hermaphrodite 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: 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 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