Invertebrate Phyla: Mollusks, Annelids, and Arthropods

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Questions and Answers

What is a characteristic shared by all mollusks?

Strong muscular foot and a feeding structure called a radula.

What is the main characteristic that distinguishes arthropods from other animals?

Jointed appendages and an exoskeleton made of chitin.

What is the significance of the blastopore in deuterostomes?

It gives rise to the anus first during embryonic development.

What are the four common characteristics of chordates?

A dorsal hollow nerve cord, notochord, pharyngeal slits, and post-anal tail. Signup and view all the answers

What is the function of epithelial cells in animal tissues?

To form a lining or covering for organs and glands. Signup and view all the answers

What is the difference between skeletal, cardiac, and smooth muscles?

Their functions and appearance; skeletal muscles are voluntary and striated, cardiac muscles are involuntary and striated, and smooth muscles are involuntary and non-striated. Signup and view all the answers

What is the principle behind negative pressure breathing?

Expanding the chest cavity creates a partial vacuum, pulling air into the lungs. Signup and view all the answers

What are the three main components of blood?

Red blood cells, white blood cells, and platelets. Signup and view all the answers

What is the main difference between open and closed circulation systems?

Open systems have a separate circulatory fluid, while closed systems use blood. Signup and view all the answers

Why are rats often used as model organisms in biology?

They are relatively small, easy to care for, and have similar anatomy to humans. Signup and view all the answers

What is the characteristic of Porifera phylum in terms of symmetry?

No symmetry Signup and view all the answers

What type of reproduction is common in Cnidaria phylum?

Asexual reproduction Signup and view all the answers

What is the characteristic of Platyhelminthes in terms of internal cavity?

Acoelomate (no internal cavity) Signup and view all the answers

What is the function of gastrovascular cavity in Platyhelminthes?

Used as both mouth and anus Signup and view all the answers

What is the characteristic of Nematoda in terms of body covering?

Covered with cuticle Signup and view all the answers

What is the characteristic of Mollusca in terms of body cavity?

Coelomate Signup and view all the answers

What is the function of mantle in Mollusca?

Secrete a shell Signup and view all the answers

What is the characteristic of Cnidaria in terms of digestion?

Extracellular digestion Signup and view all the answers

What is the characteristic of Platyhelminthes and Nematoda in terms of germ layers?

Tissues with 3 germ layers Signup and view all the answers

What is the characteristic of Nematoda in terms of digestive tract?

Complete digestive tract with a mouth and anus Signup and view all the answers

Study Notes

Lab 11: Phyla Porifera and Cnidaria

Porifera (sponges): simplest of major animal phyla, no tissue, no symmetry, asexual reproduction common, filter feeders
Cnidaria (sea jellies, coral, hydra, sea anemone): tissues with two germ layers, radial symmetry, asexual reproduction common, two life forms (medusa and polyp), have nematocyst to capture prey, extracellular digestion

Lab 12: Phyla Platyhelminthes and Nematoda

Platyhelminthes (Flatworms): acoelomate (no internal cavity), tissues with 3 germ layers, bilateral symmetry, gastrovascular cavity with one opening (used as both mouth and anus), free-living and parasitic species with different evolutionary features
Nematoda (roundworms): pseudocoelomates (have a body cavity), tissues with 3 germ layers, bilateral symmetry, covered with cuticle, complete digestive tract with mouth and anus

Lab 13: Phyla Mollusca and Annelida

Mollusca: coelomate, protostomes, well-developed organ systems, all mollusks have mantle (specialized layer of epidermal cells that secretes a shell), visceral mass, strong muscular foot, and feeding structure called a radula
Annelida (earthworms, leeches): coelomate, protostomes, well-developed organ systems, segmented

Lab 14: Phylum Arthropoda

Arthropoda: most diverse and abundant animals, jointed appendages, exoskeleton (made out of chitin)
Subgroups: Crustacean (lobsters, crabs, shrimp), Chelicerata (spiders, ticks), Myriapods (centipedes, millipedes), Insects (biggest group of arthropods, have 6 legs and 3 body parts)

Lab 15: Phyla Echinodermata and Chordata

Echinodermata (Sea stars, sea urchins, sea cucumbers): deuterostomes, radial symmetry, tube feet and water vascular system
Chordata: deuterostomes, 4 common characteristics (dorsal hollow nerve cord, notochord, pharyngeal slits, post-anal tail)
Subgroups: Shark (cartilaginous skeleton), Bony fish (swim bladder, lateral line), Amphibian (double life, need water for reproduction), Reptile (amniotic eggs, developed lung, dry skin with scales), Birds (strong flight muscles, hollow bone, endothermic, feathers), Mammals (mammary glands, hair, endothermic)

Lab 16: Animal tissues

Epithelial: simple squamous cells, cuboidal cells, glandular epithelium cells
Connective: loose connective tissues, adipose cells, dense connective tissue, blood (red blood cells and white blood cells)
Muscular: skeletal, cardiac, smooth muscles (differences in functions and appearance)
Nervous: (not observed in the lab)

Lab 17: Breathing

Negative pressure breathing: when humans inhale by expanding their lungs, creating a negative pressure that pulls air into the lungs
Diaphragm: a sheetlike muscle separating the abdomen from the chest cavity, used in breathing

Lab 18: Circulation

Blood components: red blood cells, white blood cells, platelet, plasma
Blood vessels: artery, vein, capillary (gas and nutrient exchange occurs here)
Difference between open vs. closed circulation system

Lab 19-21: Rat anatomy

Why use a rat as a model organism?
Anatomy of internal organs: need to know the name of major organs and their functions
Thoracic cavity: trachea, esophagus, heart, lung, diaphragm
Abdominal cavity: liver, stomach, small intestine, large intestine, cecum, kidney, uterine horn