THE ANIMAL KINGDOM PPt 1 Overview of Characteristics

THE ANIMAL KINGDOM (PPt #1: Overview of Characteristics)

Characteristics of Animals 1. Multicellular, eukaryotes 2. Heterotrophs 3. Cells w/out cell walls, many have specialized functions 4. Usually have a method of movement 5. Most reproduce sexually 6. Require oxygen

Describe the Body Plans of Animals 1. Symmetry: balance in body proportions 3 Types Asymmetrical. Irregular shape Bilateral: can be divided only one way to produce mirror image halves Radial symmetry: can be divided along any plane to produce 2 halves which look alike

2. Body arrangements: a. anterior: head region b. posterior: tail region c. dorsal: back or top d. ventral: abdomen or bottom

3. Body Development • As embryo develops, three germ layers form: a. Ectoderm • becomes nervous system, epidermis of the skin, pituitary, lens of eye b. • becomes muscles, skeleton, notochord, Mesoderm circulatory system, kidney, reproductive system • becomes lining of digestive tract, liver, c. pancreas, epithelial lining of lungs, many Endoderm endocrine glands

4. Body Cavities a. Acoelomatesno body cavity lined with mesoderm • EX: sponges, cnidarians, & flatworms

b. Pseudocoelomatespartial body cavity lined with mesoderm • “Tube within a tube” body plan • EX: roundworms

c. Coelomatestrue body cavity lined with mesoderm • EX: all other animals

Advantages of a body cavity (coelom or pseudocoelom): • Fluid in cavity helps distribute food, wastes, hormones, etc. from one end of animal to the other • Better distribution allows animal to grow larger • A place to put things, like new organs

5. Cephalization-concentration of sense organsdeveloped nervous system

THE ANIMAL KINGDOM OVERVIEW • Invertebrates-no backbone • Vertebrates or Chordates-backbone

Protostomes vs. Deuterostomes • Zygote cleaves to become blastula and then forms gastrula. The blastopore of the gastrula can become either the mouth or the anus of the organism • Protostome- Blastopore becomes the mouth. Ex. Annelids, Mollusks and arthropods • Deuterostome- Blastopore becomes anus. Ex. Chordates