Download Defining "Animals"

Defining "Animals"
Multicellular, Eukaryote
 Ingestive Heterotroph
 specialized tissues, nervous and muscle
 sexual reproduction - sperm and egg
 diploid stage dominate
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General comments
35 phyla
over 1,000,000 extant species
Phylum Chordata is best known (5%)
over 95% of described species are
invertebrates
Parazoa
Little or no tissue organization
Phylum Porifera
sponges
sessile
 radial symmetry?
 "plant-like"
 9000 species - mostly marine
 100 freshwater species
 filter feeder
 No true tissue or loose tissue organization
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Eumetazoa
True Tissue Layers
Endoderm – inside layer
 Mesoderm – middle layer
 Ectoderm – outside layer
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Phylum Cnidaria
made of two layers , Sac Body
radial symmetry
10,000 species - mostly marine
carnivores – Tentacles with stinging cells
Exist in two forms: polyps and medusa
Three classes
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Hydrozoa - hydra,
Scyphozoa - jellyfishes
Anthozoa - corals
Phylum Ctenophora
comb jellies
2 tissue layers
 marine
 100 species
 two tentacles – no stinging cells
 bioluminescence
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-Acoelomates
- Three Layers
- No body Cavity
Phylum Platyhelminthes
flatworms
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bilateral symmetry
acoelomates
triploblastic - endoderm, mesoderm, ectoderm
20,000 species
freshwater and marine
no respiratory or circulatory system
incomplete digestive system - no anus
Phylum Platyhelminthes
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Examples of Flatworms
Turbellaria - free living flat worms, planarians
 Trematoda - parasitic flukes
 Cestoda - parasitic tapeworms
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Pseudocoelomates
Characteristics of
Pseudocoelomates
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eumetazoa
bilateral symmetry
body cavity other than
digestive cavity
Body cavity only
partially lined with
mesoderm
Phylum Rotifera
wheel bearers animals
1800 species
 microscopic - 0.05-2.0 mm
 freshwater, usually high quality water
 complete digestive tract
 organs located in pseudocoele
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Phylum Nematoda
Round Worms
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80,000 species
freshwater, marine, terrestrial, and parasitic
complete digestive tract
tough cuticle
only longitudinal muscles
pseudocoele
parasitic
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hookworms
pinworms
trichinosis
Coeloemates
“True” Body cavity
Body cavity lined
completely lined with
mesoderm.
Phylum Annelida
Segmented Worms
15,000 species
 freshwater, marine and terrestrial
 earthworms, polychetes, leeches
 Characteristics of annelids
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segmentation
 coelom
 locomotion
 all systems complete
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Phylum Molluska
Mollusks
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50, 000 species
marine, freshwater, and terrestrial
Characteristics of mollusks
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most have external shells of calcium carbonate, although some
have internal shells and some have none
three body parts - foot, visceral mass, and mantle
mantle cavity - houses gills and other organs
no body segmentation
Examples of Molluska
chitons, snails, slugs, clams, oysters,
octopuses, and squids
Phylum Arthropoda
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1-2,000,000 species
most diversified group
freshwater, marine, and terrestrial
Characteristics of arthropods
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segmentation
hard exoskeleton
jointed appendages
specialized appendages
antennae, mouthparts, legs
moulting
variety of gas exchange or respiratory structures
Examples of Arthropods
extinct trilobites
Examples of Arthropods
horse shoe crabs, spiders, mites, scorpions
Examples of Arthropods
insects, millipeds, centipedes
Examples of Arthropods
crabs, lobsters, crayfish, shrimp, barnacles
Phylum Echinodermata
Echinoderms
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7000 species
Sand dollars, sea urchins, sea stars
spiny skin
marine
Characteristics
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radial symmetry as adults
pentagonal, five sides or five arms
endoskeleton
water vascular system
Examples of Echinodermata
starfish or sea stars
sea urchins
brittle stars
sea cucumber
sea lilies
Phylum Chordata
The Chordates
very diversified
 freshwater, marine, terrestrial
 Characteristics of chordates
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notochord
 dorsal hollow nerve chord
 pharynx slits
 muscular postanal tail
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Classification of Chordates
Subphylum Cephalochordata
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Amphioxus
Subphylum Urochordata
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sea squirts, tunicates
Classification of Chordates
Subphylum Vertebrata
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Lampreys, sharks, fish, amphibians, reptiles,
birds, and mammals
Class Agnatha
Jawless Fish – Lamprey and Hagfish
Gills
 2 chambered heart
 Cartilage skeleton
 No jaws – open “sucker”
 Parasite of Fish
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Class Chondrichthyes
Cartilaginous Fish – Sharks and Rays
2 chambered heart
 Skeleton entirely of Cartilage
 Paired fins
 Internal fertilization
 Scales
 No swim bladder
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Class Osteichthyes
Bony Fish
Skeleton made of bone
 Swim bladder
 2 chambered heart
 Most fish spawn – some live bearers
 Scales
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Class Amphibia
Frogs, Toads, Salamanders, Newts
Moist smooth skin
 Show metamorphosis
 Ectotherms
 Non-amniotic egg
 External reproduction
 Gills when young, lungs as adults
 3 chambered hearts as adults
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Class Reptilia
Lizards, Snakes, Crocodiles, Alligators
Scaly Skin
 3 Chambered heart (Croc’s have 4)
 Amniotic egg, Internal Fertilization
 Ectothermic
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Class Aves
Birds
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Feathers
Endotherms, 4
chambered heart
Internal Fertilization
Amniotic Egg
Class Mammalia
Lions, Tigers and Bears
Hair
 Mammary glands
 Diaphragm – well developed lungs
 4 chambered heart, endotherm
 Internal Fertilization
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Placental - internal development
 Marsupial – pouch development
 Monotremes – egg layers
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