EVOLUTION of Animals

EVOLUTION Animal Characteristics Evolution of Cells: prokaryotes – colonies - eukaryotes asexual - sexual reproduction unicellular – multicellular Evolution of the Animal Body: KEY FEATURES Organization of the body / Development of the embryo Types of Symmetry Deuterostome vs. Protostome (see p. 658) Special cells, tissues, organs germ layers Body cavity (coelom) Cephalization Segmentation Jointed appendages Notochord - Invertebrate  Vertebrates (Chordates) Body temperature homeostasis Reproductive characteristics

The Common Ancestor of the animal kingdom…… PROTIST group – the choanoflagellates Characteristics: heterotrophic colonial

Evolution of Animal Cells Cells: heterotrophic prokaryotes (bacteria)  colonies  unicellular, heterotrophic eukaryotes (the protists)  colonies  multicellular, heterotrophic eukaryotes (the animals) Course of development of major characteristics: Asexual  sexual reproduction Unicellular  multicellular

All about Embryonic Development embryo development: symmetry special cells, tissues, organs no germ layers – two – three body cavity = coelom no coelom - pseudocoelem - coelom

1. BODY ORGANIZATION Types of Symmetry radial bilateral Asymmetry – symmetry NOT! random organization of parts. Symmetry – the arrangement of parts around a central point or center line. Types of Symmetry radial bilateral

Development of the embryo 2. LEVELS of DEVELOPMENT special cells, tissues, organs no germ layer two germ layers three germ layers

Germ Layers in the Embryo development of specialized cells Cells begin to specialize in the blastula stage Endoderm (endo = inside) Develops into digestive tract and respiratory tissue Mesoderm (meso = middle) Develops into muscles , circulatory, reproductive, and excretory tissue Ectoderm (ecto = outside) Develops into nerves, sensory organs, skin

Development of the embryo 3. BODY CAVITY (coelom) Acoelom – all tissues are adjacent – no “cavity” Pseudocoelom – partial cavity but not throughout the body Coelom – major organs are separated by membranes, and housed in a body cavity

Germ layers and the body cavity. yellow - endoderm. red - mesoderm Germ layers and the body cavity yellow - endoderm red - mesoderm blue - ectoderm

Other major characteristics…. Cephalization development nerves/senses at the “head end” Segmentation Allows for evolution of “compartments” for special functions. Jointed appendages – take advantage of diverse environments

Invertebrate  Vertebrates (Chordates) 1st cold blooded (ectotherms)  then warm blooded (endotherms) 1st egg laying (amnion)  then placenta (live birth)

Phylum Porifera Sponges

Porifera characteristics Key feature Multicellular Characteristics Filter feeders Sessile Larval stage Marine

Phylum Cnidarians Examples jellyfish and hydra Key Feature Specialized tissues Characteristics Stinging cells Free swimming Aquatic

Platyhelminthes The Flatworms HW Use the textbook CH. 23-25.1, p. 649-714 to complete the notes for the other 7 animal phyla. INCLUDE: 1) TITLE. Underline the name of the phylum. 2) Examples (Major CLASSES and/or featured species) 3) KEY FEATURE(S) – the major feature(s) that this phylum evolved in the history of animal evolution 4) List of CHARACTERISTICS of animals of this phylum.

Notes Use the textbook and key evolutionary features from the poster assignment to complete the notes for the other 7 animal phyla.

The Platypus

Tasmanian tiger

Anaconda