Kingdom Animalia
Invertebrates to Vertebrates
General Characteristics
• Multicellular eukaryotes
• Heterotrophs that ingest their food
• Mostly sexual reproduction, some asexual
• Controlled Movement – response via nerve impulses & muscle coordination
Invertebrates vs. vertebrates
•
Evolution
• 800 MYA from motile protists that liked to hang out together
–choanoflagellates
• Movement from water to land– protection from dessication & sun’s
rays
Move from water to land determines changes in…
• Body support & movement• Reproduction • Circulatory system• Respiratory system• Digestive and excretory system• Nervous system
Common morphology
• 3 categories of morphology for classification and evolutionary advances–Symmetry–Germ layers–Body cavity
symmetry
Advantages of bilateral symmetry
– Allow for cephalization• Centralized nervous system in a head
– Allows for segmentation• Specialization of body parts
– Allows for one way digestive system• Input (eating) to output (excretion) that
flows in one direction vs. a 2-way system
Germ layers• Ectoderm
-becomes hair, skin, nervous system • Mesoderm
-becomes skeleton, muscle, inner skin, circulatory system, liver
• Endoderm– becomes gut and associated organs,
lungs, gills, pancreas, and their linings
Body Cavity• Acoelomate
–Solid organism–restricted movement &
function• Psuedocoelomate
–False body cavity
Body Cavity, cont’d
Coelomate– True body cavity – body cavity surrounded by
mesoderm– Allows for ease of mobility & function, i.e.
digestion, circulation– More room for larger organs (or coiled organs)
so processes can take longer/efficiency– Allows for retention of eggs/gametes
• Internal fertilization (protects young)
Patterns of Development
• Type of cleavage determines whether or not cells can regenerate and ease of cloning
Patterns of Development• Indirect
–Metamorphosis through a life cycle
vs.
Direct
-growth & differentiation
Earliest animals - sponges
• Phylum Porifera• Collection of cells, able to
communicate with each other
• No true tissue layers• No symmetry or organs• Sessile, suspension feeders• O&D• regeneration
First true animals
• Phylum Cnidarian– Jellies, anemones, hydra,
corals
• Phylum Ctenophora– Comb jellies– 2 (?) true tissue layers but
lacking in complex systems– Sexual reproduction– Radial Symmetry
Early Worms• Phylum Playthelminthes
– flatworms
• Phylum Nematoda– Round worms
Phylum Mollusca• 1st with true coelum
• The “head-foods”
• Radula
Phylum Annelida
• Earthworms (segmented worms)
• Hermaphrodites
• Do NOT regenerate!!
Phylum Arthropoda• Largest phylum, essential for evo. Of plants
• Exoskeleton limits size– Crayfish, insects, lobsters, spiders
– Jointed appendages
Phylum Echinodermata• First deuterostomes, closely related to us
• Starfish, sea urchins– “Spiny skin”
Phylum Chordata
• Dorsal nerve chord
• Notochord
• Pharyngeal (gill) slits
• Post-anal tail– Classes – birds,
reptiles, amphibians, mammals
Top Related