What is an Invertebrate?

Internal skeleton is not unique to vertebrates. (Starfish has an internal skeleton)

What is an Invertebrate? Internal skeleton is not unique to vertebrates. (Starfish has an internal skeleton) Vertebrate animals: the brain is encased in a bony skull.

What is an Invertebrate? Internal skeleton is not unique to vertebrates. (Starfish has an internal skeleton) Vertebrate animals: the brain is encased in a bony skull. Nervous system of true invertebrates are different from true vertebrates.

Characteristics of Invertebrates

Locomotion and Support.

Characteristics of Invertebrates Locomotion and Support. Muscles and Skeletons.

Characteristics of Invertebrates Locomotion and Support. Muscles and Skeletons. Feeding mechanisms.

Characteristics of Invertebrates Locomotion and Support. Muscles and Skeletons. Feeding mechanisms. Excretion and Osmoregulation.

Characteristics of Invertebrates Locomotion and Support. Muscles and Skeletons. Feeding mechanisms. Excretion and Osmoregulation. Circulation and Gas Exchange.

Characteristics of Invertebrates Locomotion and Support. Muscles and Skeletons. Feeding mechanisms. Excretion and Osmoregulation. Circulation and Gas Exchange. Nervous System and Sense Organs.

Locomotion and Support (Protozoa and Metazoa) Four fundamental locomotor patterns. I. Ameboid movement. II. Ciliary and flagellar movement. III. Hydrostatic propulsion. IV. Locomotor limb movement.

I. Ameboid movement. Ameboid locomotion is used by certain protists and by numerous kinds of ameboid cells that are located within the bodies of most Metazoa.

(gel-like) (more fluid) Complex changes in cell fine structure, chemistry, and behavior.

Mechanisms of Ameboid movement.

HELIOZOANS ACTINOPHRYS SP. I COLLECTED THIS ONE IN WISCONSIN. Axopodia

Ameboid locomotion used for body maintenance

II. Ciliary and flagellar movement. Cilia and/or flagella occur in every animal phylum with the exception of the Arthropods.

Figure 3.7 Cilia and Flagella anatomy!

This is the pattern characteristic of nearly all flagella and cilia.

Cilia move in waves: metachronal waves. Usually many. Undulatory movement Power stroke or oar like action Usually few.

Overlap of microtubular and fibrous kinetosomes that provide a structural lattice.

Cilia architecture variation.

Cilia and flagella used for feeding

Comb Jellies Phylum Ctenophora are the larges animals known to rely primarily on cilia for locomotion.

Macrocilia

III. Hydrostatic propulsion. Based on two fundamental properties of liquids: their incompressibility and their ability to assume any shape. Limitation of muscles: They can only perform work by contracting.

Sipunculan worm.

Peristalsis

Tube-within-a-tube Pseudocoelomates Coelomates

Phylum Annelida, Class Polychaeta

Phylum Echinodermata: Oreaster reticulatus Family Oreasteridae

Tube foot from an echinoderm, ampulla, radial canal, lateral canal, podium are shown.

Phylum Echinodermata: Astichopus multifidus Family Stichopodidae

IV. Locomotor limb movement. Rigid skeleton. Muscles.

Rigid skeleton. Endoskeleton: Derived from mesoderm. Exoskeleton: Derived from ectoderm. ----Both have organic and inorganic components. Most skeletons act as body elements against which muscles operate by which muscle action is converted to body movement.

Muscles. Animals that possess rigid but articulate skeletons have antagonistic muscles often appearing in pairs (flexors and extensors).

Protractors and retractors; adductors and abductors.

The Big Picture The four fundamental locomotor patterns and the three skeletal systems define how invertebrates function. Locomotor patterns of invertebrates can be divided into ameboid movement, ciliary and flagellar movement, hydrostatic propulsion, and locomotor limb movement. Skeletal systems of invertebrates can be divided into hydrostatic skeletons, endoskeletons, and exoskeletons. Each of these categories have numerous variation.