Domain Eukarya Kingdom Animalia Evolutionary trends among organisms

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. 2. 3. 4. 5. Development Symmetry Segments Cephalization 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 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 • Coelom – Fluid filled body cavity that houses internal organs – Acoelomate – no body cavity (simple animals) – Coelomate – true body cavity (complex animals) Coelom No Coelom Internal Organ

Coelom in Humans

Importance of Evolutionary Trends Evolutionary Trend Protostome or Deuterostome Importance More complex animals are deuterostomes Specialized cells and organs (ie. Observed in complex animals circulatory, respiratory, etc) Cephalization Can responds and react to surroundings better Segmentation Allows invertebrates in increase in size Coelom Allows for space for specialized organs

Invertebrates -vs- Vertebrates

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

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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