Domain: Eukarya Kingdom: Animalia Evolutionary trends among organisms within the Kingdom Animalia

What is an animal? Multicellular Eukaryotic Heterotrophic Lack cell walls Vertebrate –Backbone Invertebrate –No Backbone

Evolutionary Trends in Animals 1.Development 2.Symmetry 3.Segments 4.Cephalization 5.Coelom (body cavity)

Development Gametes (sex cells) –Unite to form Zygote Blastula –Zygote that has divided and began to hollow out Protosome –Mouth develops first Deuterostome –Anus develops first

Germ Layers of Development 1. Endoderm – inner layer Leads to development of digestive and respiratory system 2. Mesoderm – middle layer Leads to development of muscles, circulatory, reproductive and excretory systems

Germ Layers of Development 3. Ectoderm – outer layer Leads to development of sense organs, nerves, and skin Cells in each layer can be traced to later development Implication  Stem Cell Treatment

Symmetry Types of Symmetry 1.Radial body parts arranged around a central point 2.Bilateral divided into 2 equal halves

Symmetry Symmetry Terms 1.Anterior – towards head 2.Posterior – towards bottom 3.Ventral – towards front 4.Dorsal – towards back

Identify the Symmetry Terms Front

Segments and Cephalization Segmentation –Repeating body segments –More important for invertebrates Cephalization –Concentration of sense organs and nerves at front of animal

Coelom –Fluid filled body cavity that houses internal organs –Acoelomate – no body cavity (simple animals) –Coelomate – true body cavity (complex animals) No Coelom Internal Organ

Coelom in Humans

Importance of Evolutionary Trends Evolutionary TrendImportance Protostome or DeuterostomeMore complex animals are deuterostomes Specialized cells and organs (ie. circulatory, respiratory, etc) Observed in complex animals CephalizationCan responds and react to surroundings better SegmentationAllows invertebrates in increase in size CoelomAllows for space for specialized organs

Invertebrates -vs- Vertebrates

Evolutionary Trends in Invertebrates Radial Symmetry Coelom Pseudocoelom Protostome Development Radial Symmetry Three Germ Layers; Bilateral Symmetry Tissues Multicellularity ChordatesEchinoderms Arthropods Annelids Mollusks Roundworms Flatworms Cnidarians Single-celled ancestor Deuterostome Development Sponges

Evolutionary Trends in Invertebrates 1.Feeding and Digestion 2.Circulation 3.Movement and Support

Feeding and Digestions 1.Intracellular Digestions Individual cells break down material and it diffuses to other cells Usually only 1 opening

Feeding and Digestion 2.Extracellular Digestions Digestive system responsible for breaking down food, not individual cells 2 openings

Circulation 1.Open System Blood is partially contained Observed in Arthropods and mollusks

Circulation 2.Closed System Heat or “heart- like” organ pumps blood through vessels Larger, more active animals

Movement and Support 1.Hydrostatic Skeleton Use fluid force to move body parts Worms 2.Exoskeleton Hard covering Spiders 3.Endoskeleton Support found on inside the body Sea stars

Movement and Support

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