Chapter 28 notes

A RE HETEROTROPHS : consume food N O CELL WALL: cells only have cell membranes D I PLOID: cells have 2 of each chromosome M ULTICELLULAR: made of many cells ST A GES OF DEVELOPMENT: from zygote to gastrula L OCOMOTION: swim, crawl, run, fly, walk…. S EXUAL REPRODUCTION: union of gametes ADD THE CHARACTERISTIC NOT MENTIONED IN THE ACROSTIC ABOVE: Cells are organized into tissues that have specific functions

ANIMAL EVOLUTIONARY MILESTONES PORIFERA (earliest) Multicellularity (many cells) CNIDARIA Tissues (specialized groups of cells) PLATYHELMINTHES Bilateral symmetry (2 identical halves) NEMOTODA Pseudocoelom (false body cavity) MOLLUSCA Coelom (true body cavity) ANNELIDA segmentation (body made of segments) ARTHROPODA jointed appendages (parts have joints) ECHINODERMATA deuterostomes (gastrula opening becomes anus) CHORDATA (most recent) Notochord (flexible rod of tissue along back)

Identify these stages of development: ZYGOTE2 CELLS8 CELLSBLASTULAGASTRULA ECTODERM ENDODERM MESODERM

BILATERAL BODY PLANS: Body Plan and animal example Drawing with labelsGive advantages Acoelomate: FLATWORM ECTODERM MESODERM ENDODERM Nutrients and wastes diffuse through solid three layer organism Pseudocoelomate: ROUNDWORM ECTODERM MESODERM ENDODERM PSEUDOCOELOM Muscle can push against fluid filled cavity to produce whip-like movement Coelomate: SEGMENTED WORM ECTODERM MESODERM ENDODERM COELOM Organs are suspended and protected within a true body cavity. Animals can move about without damaging organs

Bilateral Symmetry: identical halves Anterior (head region) Posterior (tail region) Dorsal (back) Ventral (belly)

Types of symmetry Type of symmetry DefinitionBenefit to the animal Radial Body parts are arranged around a central axis Can detect movement from all directions Bilateral Distinct right and left halves Specialized body parts More complex movements Asymmetrical Irregular in shape: no symmetry Shape depends upon location of growth Sessile (anchored) due to difficulty in moving