4 - Invertebrates.pdf

THE INVERTEBRATES ZOOL111 | Lesson 4 Amanda S. De Los Santos, MS An animal phylogenetic tree based on body plans and molecular data simplified version OUTLINE OF DISCUSSION 01 Ctenophora 04 Lophotrochozoa 02 Porifera 0...

THE INVERTEBRATES ZOOL111 | Lesson 4 Amanda S. De Los Santos, MS An animal phylogenetic tree based on body plans and molecular data simplified version OUTLINE OF DISCUSSION 01 Ctenophora 04 Lophotrochozoa 02 Porifera 05 Ecdysozoa 03 Cnidaria 06 Deuterostomia  01 CTENOPHORA Ctenophores Comb Jellies  Greek Ctenophora ktenos = comb Phora = bearing ➔ have on their surfaces eight rows of cilia that resemble combs ➔ about 1–10 cm in length ➔ probably the largest animals to use cilia for locomotion ➔ possess two long tentacles ➔ Hermaphrodites ➔ exhibit bioluminescence  02 PORIFERA Poriferans The Sponges Porifera Latin, meaning pore bearers ➔ multicellular and produce different types of specialized cells ➔ range in size from only a few millimeters across to more than 2 m in diameter ➔ adult sponges are sessile while the larvae are free-swimming Porifera Latin, meaning pore bearers ➔ Choanocytes Help Circulate Water ➔ Sponges Have Mechanical and Chemical Defenses Against Predators ➔ Sponges Reproduce Sexually and Asexually  03 CNIDARIA Cnidarians Jellyfish & Other Radially Symmetric Animals Cnidaria Greek knide = nettle ; aria = related to ➔ mostly found in marine environments, although a few are freshwater species ➔ have tentacles around the mouth that aid in prey detection and capture The distinguishing characteristics of Cnidarians Cnidarians Exist in Two Different Body Forms Cnidarians Have Specialized Stinging Cells 04 LOPHOTROCHOZOA The Flatworms, Rotifers, Bryozoans, Brachiopods, Mollusks, and Annelids  Platyhelminthes The Flatworms with No Coelom ➔ respire by diffusion ➔ lack a coelem—a fluid- filled body cavity in which the gut is suspended ➔ Incomplete digestive system ➔ have a distinct excretory system consisting of protonephridia Platyhelminthes The Flatworms with No Coelom ➔ Reproduction is either sexual or asexual Rotifera The Rotifers ➔ ciliated crown, or corona, which, when beating, looks similar to a rotating wheel ➔ bears a jointed foot with one to four toes ➔ Pedal glands in the foot secrete a sticky substance that aids in attachment to a substrate. Rotifera The Rotifers ➔ internal organs of lie within a pseudocoelom ➔ have an alimentary canal, a digestive tract with a separate mouth and anus ➔ mouth opens into a circular, muscular pharynx called a mastax, which has jaws for grasping and chewing ➔ Reproduction can be through parthenogenesis Bryozoa & Brachiopoda The Bryozoans and Brachiopods ➔ both possess a lophophore, a ciliary feeding device ➔ have a U-shaped alimentary canal, with the anus located near the mouth but outside of the lophophore An animal phylogenetic tree based on body plans and molecular data simplified version Mollusca The Snails, Slugs, Clams, Oysters, Octopuses, and Squids ➔ have soft body, which in many species is found under a protective external shell Mollusca The Snails, Slugs, Clams, Oysters, Octopuses, and Squids ➔ Most have open circulatory system with a heart that pumps a body fluid called hemolymph through vessels and into sinuses ➔ Excretory organs called metanephridia remove nitrogenous and other wastes ➔ have separate sexes, although some exist as hermaphrodites Annelida The Segmented Worms ➔ range in size from less than 1 mm to enormous 3 m ➔ Consists of adjacent segments that are separated by septa ➔ have a nervous system with a pair of cerebral ganglia that connect to a subpharyngeal ganglion Annelida The Segmented Worms ➔ possess a fluid-filled coelom that acts as a hydrostatic skeleton ➔ All annelids except the leeches have chitinous bristles, called setae, on each segment ➔ have a closed circulatory system ➔ respiration occurs directly through the permeable skin surface ➔ Reproduction can be asexual or sexual Annelida The Segmented Worms  05 ECDYSOZOA The Nematodes and Arthropods Nematoda The Small Pseudocoelomate Worms Covered by a Tough Cuticle ➔ small, thin worms that range in size from less than 1 mm to about 5 cm ➔ ubiquitous organisms that exist in nearly all habitats, from the poles to the tropics ➔ found in the soil, in both freshwater and marine environments, and inside plants and animals as parasites ➔ Has tough cuticle that covers their body Arthropoda The Species with Jointed Appendages ➔ Covered by a hard cuticle, an exoskeleton, made of layers of chitin and protein ➔ segmented, and many of the segments bear jointed appendages Arthropoda The Species with Jointed Appendages ➔ have multiple sensory organs, including organs of sight, touch, smell, hearing, and balance ➔ have compound eyes composed of many independent visual units called ommatidia ➔ have an open circulatory system Major Orders and Characteristics of Insects  06 DEUTEROSTOMIA The Echinoderms and Chordates Echinodermata The Sea Stars and Sea Urchins ➔ have modified radial symmetry ➔ Most echinoderms have an endoskeleton ➔ possess a true coelom, and a portion of the coelom has been adapted to serve as a unique water vascular system ➔ exhibit autotomy, the ability to intentionally detach a body part, such as a limb, that will later regenerate Echinodermata The Sea Stars and Sea Urchins ➔ cannot osmoregulate, so no species have entered freshwater environments ➔ Coelomic fluid circulates around the body. ➔ No excretory organs present ➔ Most echinoderms reproduce sexually and have separate sexes Chordata All Vertebrates and Some Invertebrates (Tunicates & Lancelets) ➔ Notochord ➔ Dorsal hollow nerve cord ➔ Pharyngeal slits ➔ Postanal tail Invertebrate chordates Subphylum Cephalochordata (lancelets) Subphylum Urochordata (tunicates) Chordata All Vertebrates and Some Invertebrates (Tunicates & Lancelets) An animal phylogenetic tree based on body plans and molecular data simplified version SUMMARY Ctenophora Lophotrochozoa Porifera Ecdysozoa Cnidaria Deuterostomia  THANK YOU! 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