CH 24 WHAT IS AN ANIMAL?

CHARACTERISTICS OF ALL ANIMALS Eukaryotic Multicellular (metazoans) Specialized cells (tissues & organs) Ingestive heterotrophs

SEXUAL REPRODUCTION (MOST) Sperm + Egg = Zygote Cleavage -> zygote divides Embryo -> an organism in the early stages of development

CELL LAYERS (MOST HAVE THREE) Ectoderm - outer layer (skin & nervous tissue Endoderm - inner layer (digestive organs) Mesoderm - middle layer (muscles, circulatory, excretory and respiratory systems

SYMMETRY Radial - round, or sphere shaped Bilateral - R & L halves form mirror images Asymmetrical – no definite shape

BODY PLANES Dorsal - back surface Ventral - belly surface Anterior - top (head) Posterior - tail end

BODY CAVITIES Coelum - fluid-filled cavity / mesoderm (earthworms) Acoelomate - no body cavity (flatworms)

STRUCTURES FOR SUPPORT AND DEVELOPMENT Vertebrates - have an internal backbone - (endoskeleton) Invertebrates - lack a backbone - most have an exoskeleton

MICROSCOPE PROCEDURES

Parts of the Microscope

1. Carry with both hands

2. Unwrap and plug in the cord. Turn on the light 2. Unwrap and plug in the cord. Turn on the light. Turn the coarse and fine adjustment knobs until the stage is close to the objective.

3. Start on low power 4X which = 40X or 10X which = 100X NOT 40X which = 400X

4. Put slide on stage - Apply stage clips

5. Turn coarse adjustment knob ¼ – ¾ turn. Find and focus.

6. Make sure the specimen is in the middle of the field of view before switching to high power.

7. Flip the high power objective lens (400x) into place 7. Flip the high power objective lens (400x) into place. Refocus using ONLY the fine adjustment.

If you lose your specimen when switching to high power you must refocus on low power again before switching to high power.

8. Remove the slide when finished.

9. Turn off the light. Return to low power.

10. Wrap cord correctly. Show microscope to your teacher 10. Wrap cord correctly. Show microscope to your teacher. Return microscope to cart.