Key Concepts:
All animals are multicelled, aerobic heterotrophs
Animals originated about 900 million years ago
Comparisons of body plans of existing animals with fossil records reveal that there were several trends in the evolutions of certain lineages
Key Concepts:
Divergences gave rise to two major lineages: those of the mollusks, annelids, and arthropods and the other one to the echinoderms and chordates
The arthropods, especially the insects, have been the most successful animal groups
Overview of the Animal Kingdom
Animals Multicellular Heterotrophs Oxygen is required Sexual reproduction (some asexual) Motile - in part of life cycle Embryonic development Mitotic cell divisions in embryo
Tissue layers
•Ectoderm, Endoderm, Mesoderm
Diversity in Body Plans
Vertebrates Mammals
birds, reptiles, amphibians, fishes
Invertebrates No backbones
Body symmetry & Cephalization ( sense in the head) Gut
Body cavity
Segmentation
Flatworms:Turbellarians, Flukes & Tapeworms
Nervous system in a Planarian
Reproductive system in a Planarian
Roundworms
Most abundant multicelled animal Bilateral symmetry
Cylindrical body
Cuticle
Complete digestive system
Male and female
A Sampling of Mollusks
Mollusk Soft body
Shell
Mantle
Fleshy foot
Gastropods-snails
Chitons
Bivalves-clams
Cephalopods-squid
Arthropods: The Most Successful Organisms on
Earth-Arthropods
Over one million species
Trilobites (extinct)
Chelicerates Spiders
Crustaceans Barnacles and crabs
Uniramians Centipedes, millipedes, insects
Adaptations of Insects and Other Arthropods
Hardened exoskeleton
Jointed appendages
Fused and modified segments
Respiratory structures
Specialized Sensory Structures
Division of labor
A Look at Insect Diversity
Head, thorax, abdomen
Sensory antennae
Mouthparts
3 pairs of legs
2 pairs of wings
Malphigian tubules Waste disposal
Life cycles
The Puzzling Echinoderms
EchinodermsSea star
Sea urchin
Sea cucumber
Brittle stars
Body walls
Spines, spicules
Radial symmetry
Decentralized nervous system
Water-vascular system
In Conclusion
Animals are multicellular, aerobic heterotrophs that ingest or parasitize other organisms
Animals range from structurally simple placozoans and sponges to vertebrates
In Conclusion
Almost all animals more complex than cnidarians show bilateral symmetry, form tissues, organs, and organ systems
All mollusks have a fleshy soft body, and a mantle
In Conclusion
The annelids, have a segmented body, complex organs, and coelomic chambers
Arthropods are the most successful of all groups in terms of diversity, numbers, distribution, defenses, and capacity to exploit food resources
Echinoderms have spines, spicules, or plates in their body wall
developed by M. Roig