Phyla of Animals: Porifera, Cnidaria, Platyhelminthes, and Nematoda

Phyla Porifera and Cnidaria

• Porifera (sponges) are the simplest of the major animal phyla, characterized by no tissue, no symmetry, and asexual reproduction being common, and are filter feeders.
• Cnidaria (sea jellies, coral, hydra, sea anemone) have tissues with two germ layers, radial symmetry, and asexual reproduction is common, and they have two types of life forms (medusa and polyp) and nematocysts to capture prey.

Phyla Platyhelminthes and Nematoda

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

Phyla Mollusca and Annelida

• Mollusca are coelomate, protostomes, and have well-developed organ systems.
• All mollusks have a mantle (specialized layer of epidermal cells that secretes a shell) and a visceral mass.
• Most mollusks have a strong muscular foot and a feeding structure called a radula.
• Subgroups of Mollusca include Gastropod (snail, slug), Cephalopod (squid, octopus), and Bivalvia (clam, scallop).
• Annelida (earthworms, leeches) are coelomate, protostomes, and have well-developed organ systems, and are segmented.

Phylum Arthropoda

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

Phyla Echinodermata and Chordata

• Echinodermata (sea stars, sea urchins, sea cucumbers) are deuterostomes (blastopore gives rise to an anus first), have radial symmetry when fully grown, and have tube feet and a water vascular system.
• Chordata are deuterostomes, and have 4 common characteristics (a dorsal hollow nerve cord, notochord, pharyngeal slits, and post-anal tail).
• Subgroups of Chordata include 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), and Mammals (mammary glands, hair, endothermic).

Animal Tissues

• Epithelial tissues include simple squamous cells (cheek cells), cuboidal cells (kidney), and glandular epithelium cells (liver).
• Connective tissues include loose connective tissues, adipose cells, dense connective tissue (tendon and ligament), and blood (red blood cells and white blood cells).
• Muscular tissues include skeletal, cardiac, and smooth muscles (need to know the differences between these three muscle types in terms of their functions and appearance).
• Nervous tissues were not observed in the lab.

Breathing

• Negative pressure breathing occurs when humans inhale by expanding their lungs, creating a negative pressure that pulls air into the lungs.
• The diaphragm is a sheetlike muscle that separates the abdomen from the chest cavity, and is used in breathing.
• When the diaphragm contracts, it flattens and expands the chest cavity, causing a negative pressure (partial vacuum), thereby pulling air into the lungs.

Circulation

• Blood components include:
  • Red blood cells: lack nuclei, made by bone marrow, transport gas
  • White blood cells: have nuclei, made by bone marrow, involved in the immune system
  • Platelet: cause blood clotting
  • Plasma: liquid part of the blood tissue, carries dissolved materials
• Blood vessels include:
  • Artery: transport blood away from the heart
  • Vein: transport blood to the heart
  • Capillary: thin membrane, connects arteries and veins, gas and nutrient exchange occurs here
• Difference between open vs. closed circulation system.

Phyla Porifera and Cnidaria

• Porifera (sponges) are the simplest of the major animal phyla, lacking tissues and symmetry, and reproducing asexually.
• They are filter feeders.
• Cnidaria (sea jellies, coral, hydra, sea anemone) have tissues with two germ layers and radial symmetry.
• Asexual reproduction is common in Cnidaria, and they have two types of life forms (medusa and polyp).
• They have nematocyst to capture prey and undergo extracellular digestion.

Phyla Platyhelminthes and Nematoda

• Platyhelminthes (Flatworms) are acoelomate, with tissues having 3 germ layers and bilateral symmetry.
• They have a gastrovascular cavity with one opening used as both mouth and anus.
• Both free-living and parasitic species exist, with different evolutionary features.
• Nematoda (roundworms) are pseudocoelomates, with tissues having 3 germ layers and bilateral symmetry.
• They are covered with cuticle and have a complete digestive tract with a mouth and anus.

Phyla Mollusca and Annelida

• Mollusca are coelomate, protostomes with well-developed organ systems.
• They have a mantle (specialized layer of epidermal cells that secretes a shell) and a visceral mass.
• Most mollusks have a strong muscular foot and a feeding structure called a radula.
• Subgroups of Mollusca include Gastropod (snail, slug), Cephalopod (squid, octopus), and Bivalvia (clam, scallop).
• Annelida (earthworms, leeches) are coelomate, protostomes with well-developed organ systems and are segmented.

Phylum Arthropoda

• Arthropoda are the most diverse and abundant animals, characterized by jointed appendages and an exoskeleton made out of chitin.
• Subgroups of Arthropoda include Crustacean (lobsters, crabs, shrimp), Chelicerata (spiders, ticks), Myriapods (centipedes, millipedes), and Insects (biggest group of arthropods, with 6 legs and 3 body parts).

Phyla Echinodermata and Chordata

• Echinodermata (Sea stars, sea urchins, sea cucumbers) are deuterostomes, with radial symmetry when fully grown.
• They have tube feet and a water vascular system.
• Chordata are deuterostomes, characterized by 4 common characteristics: a dorsal hollow nerve cord, notochord, pharyngeal slits, and post-anal tail.
• Subgroups of Chordata include 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), and Mammals (mammary glands, hair, endothermic).

Animal Tissues

• Epithelial tissues consist of simple squamous cells (cheek cells), cuboidal cells (kidney), and glandular epithelium cells (liver).
• Connective tissues include loose connective tissues, adipose cells, dense connective tissue (tendon and ligament), and blood (red blood cells and white blood cells).
• Muscular tissues include skeletal, cardiac, and smooth muscles, which differ in terms of their functions and appearance.

Breathing

• Negative pressure breathing occurs when humans inhale by expanding their lungs, creating a negative pressure that pulls air into the lungs.
• The diaphragm is a sheetlike muscle separating the abdomen from the chest cavity, used in breathing.
• When the diaphragm contracts, it flattens and expands the chest cavity, causing a negative pressure that pulls air into the lungs.

Circulation

• Blood components include red blood cells (lack nuclei, transport gas), white blood cells (have nuclei, involved in the immune system), platelet (cause blood clotting), and plasma (liquid part of the blood tissue, carries dissolved materials).
• Blood vessels include arteries (transport blood away from the heart), veins (transport blood to the heart), and capillaries (thin membrane, connects arteries and veins, gas and nutrient exchange occurs here).
• There is a difference between open and closed circulation systems.

Phyla Porifera and Cnidaria

• Porifera (sponges) lack tissue and symmetry and have asexual reproduction, and are filter feeders.
• Cnidaria (sea jellies, coral, hydra, sea anemone) have tissues with two germ layers, radial symmetry, and asexual reproduction, with two types of life forms (medusa and polyp).
• Cnidaria have nematocysts to capture prey and use extracellular digestion.

Phyla Platyhelminthes and Nematoda

• Platyhelminthes (Flatworms) are acoelomate, have tissues with 3 germ layers, bilateral symmetry, and a gastrovascular cavity with one opening (used as both mouth and anus).
• They have free-living and parasitic species with different evolutionary features.
• Nematoda (roundworms) are pseudocoelomates, have tissues with 3 germ layers, bilateral symmetry, and are covered with cuticle.
• They have a complete digestive tract with a mouth and anus.

Phyla Mollusca and Annelida

• Mollusca are coelomate, protostomes, and have well-developed organ systems.
• All mollusks have a mantle (specialized layer of epidermal cells that secretes a shell) and visceral mass.
• Most mollusks have a strong muscular foot and a feeding structure called a radula.
• Subgroups of Mollusca include Gastropod (snail, slug), Cephalopod (squid, octopus), and Bivalvia (clam, scallop).
• Annelida (earthworms, leeches) are coelomate, protostomes, and have well-developed organ systems and are segmented.

Phylum Arthropoda

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

Phyla Echinodermata and Chordata

• Echinodermata (Sea stars, sea urchins, sea cucumbers) are deuterostomes, have radial symmetry when fully grown, and have tube feet and a water vascular system.
• Chordata are deuterostomes and have 4 common characteristics: a dorsal hollow nerve cord, notochord, pharyngeal slits, and post-anal tail.
• Subgroups of Chordata include 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), and Mammals (mammary glands, hair, endothermic).

Animal Tissues

• Epithelial tissues include simple squamous cells (cheek cells), cuboidal cells (kidney), and glandular epithelium cells (liver).
• Connective tissues include loose connective tissues, adipose cells, dense connective tissue (tendon and ligament), and blood (red blood cells and white blood cells).
• Muscular tissues include skeletal, cardiac, and smooth muscles (differing in function and appearance).
• Nervous tissues were not observed in the lab.

Breathing

• Negative pressure breathing occurs when humans inhale by expanding their lungs, creating a negative pressure and pulling air into the lungs.
• The diaphragm is a sheetlike muscle separating the abdomen from the chest cavity, used in breathing.
• When the diaphragm contracts, it flattens and expands the chest cavity, causing negative pressure, and pulls air into the lungs.

Circulation

• Blood components include:
  • Red blood cells: lack nuclei, made by bone marrow, transport gas
  • White blood cells: have nuclei, made by bone marrow, involved in the immune system
  • Platelet: cause blood clotting
  • Plasma: liquid part of the blood tissue, carries dissolved materials
• Blood vessels include:
  • Artery: transport blood away from the heart
  • Vein: transport blood to the heart
  • Capillary: thin membrane, connects arteries and veins, gas and nutrient exchange occurs here
• Open vs. closed circulation systems differ in their circulatory pathways.

Learn about the characteristics of four animal phyla: Porifera, Cnidaria, Platyhelminthes, and Nematoda. Understand their unique features, body structure, and reproductive methods.