32-2: Comparison of Invertebrates + Vertebrates

Invertebrate characteristics  Symmetry Radial or bilateral  Aquatic Terrestrial  Aquatic – radial; Terrestrial – bilateral BRAIN  Most animals display bilateral for motility + sensory functioning (i.e. a BRAIN)  Segmentation A body composed of a series of repeating similar units  Simple (earthworm) to complex (Arthropods)

Let’s look at these two…  Symmetry  Segmentation

Invertebrate characteristics  Support of the body Simple skeletons  Ex. Sponges Pressure fluid-filled cavity  Ex. Roundworms Exoskeleton – rigid outer covering  Ex. Lobster + clam

Invertebrate characteristics  Respiratory + Circulatory Systems Gas exchange – CO 2 + O 2 in blood Circulatory system – moves blood or fluid ( hemolymph ) through body to transport nutrients or O 2 to cells  Types of circulatory systems: Diffusion – Ex. Sponges + Cnidarians Open – bloodlike fluid pumped from vessels into body cavity, then pumped back; Ex. Grasshopper Closed – blood circulates through body in tubular vessels; Ex. Earthworm

Let’s look at these two…  Respiratory  Circulatory

Invertebrate characteristics  Digestive + Excretory systems Digestion  Sponges –occurs in individual cells  Cnidarians – central chamber  Most others have a digestive tract (gut) to breakdown food to absorb nutrients Excretion – removal of wastes  Aquatic – wastes are excreted as dissolved ammonia (NH 3 )  Terrestrial – wastes are filtered before removed; water gets reabsorbed

Let’s look at these two…  Digestive  Excretory

Invertebrate characteristics  Nervous System Sponges  No neurons – nerve cells  Individual cells can react to external stimuli Most other organisms may have some sort of cephalization

Invertebrate characteristics  Reproduction + Development Capable of both sexual + asexual hermaphrodites Some are hermaphrodites  Organism that produces both male + female gametes Ex. Earthworm Indirect development Indirect development  Larval stage - change of appearances Direct development Direct development  No larval stage  Animal is born or hatched – no change in appearance

Let’s look at these two…  Indirect  Direct

Vertebrate characteristics  All vertebrate classes, except fish, spend part or all of their life on land  Categories for terrestrial adaptations: Support of body Conservation of water

Vertebrate Characteristics – highlights  Have the following: Body support – endoskeletons (backbone/vertebrae) Body covering – integument Gas exchange – lungs/gills Circulatory - multichambered heart Digestive – gut (mouth to anus) = 23 ft long in humans Excretory – kidneys Nervous – highly organized brains Reproduction – fertilization of egg (zygote) Development – direct development, except amphibians