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Chapters 24, 25, 26, and 27 KINGDOM ANIMALIA INVERTEBRATES.

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Presentation on theme: "Chapters 24, 25, 26, and 27 KINGDOM ANIMALIA INVERTEBRATES."— Presentation transcript:

1 Chapters 24, 25, 26, and 27 KINGDOM ANIMALIA INVERTEBRATES

2  Phylum Porifera (ex. Sponge & sea cucumber)  Phylum Cnidaria (ex. jellyfish & hydra)  Phylum Platyhelminthes (ex. Planaria & fluke)  Phylum Nematoda (ex. hookworms & pinworms)  Phylum Mollusca (ex. Octopus, snail, & oyster)  Phylum Annelida (ex. Earthworm & leech)  Phylum Arthropoda (ex. Insects, arachnids, & crustaceans)  Phylum Echinodermata (ex. Sea urchin & sand dollar)  Phylum Chordata (ex. Lancelet & tunicates) INVERTEBRATE PHYLA

3 INVERTEBRATE EVOLUTION 1.Phylum Porifera 2.Phylum Cnidaria 3.Phylum Platyhelminthes 4.Phylum Nematoda 5.Phylum Mollusca 6.Phylum Annelida 7.Phylum Arthopoda 8.Phylum Echinodermata 9.Phylum Chordata

4  Organisms in the phylum Porifera are among the simplest animals  Many sponges are radially symmetrical  Their parts are arranged around a central axis  Choanocytes are specialized cells that make up poriferans. PHYLUM PORIFERA *CELLULAR LEVEL OF ORGANIZATION Central axis

5 PHYLUM PORIFERA  Filter feeders:  Flagellated choanocytes filter food from the water passing through the porous body  Sessile: stay in one place Figure 18.3C Pores WATER FLOW Skeletal fiber Central cavity Choanocyte Amoebocyte Choanocyte in contact with an amoebocyte Flagella

6 PHYLUM PORIFERA Single cell Stalk  The sponge lineage arose very early.  They probably evolved from multicellular choanoflagellates, the group that most likely gave rise to the animal kingdom.

7  Cnidarians are the simplest animals with tissues.  These animals exist in two radially symmetrical forms:  Polyp  Medusa PHYLUM CNIDARIA *TISSUE LEVEL ORGANIZATION

8  Cnidocytes on their tentacles sting prey –The tentacles, controlled by nerves, then push the food through the mouth into a gastrovascular cavity. –In the cavity, the food is digested and then distributed. –Only one opening in digestive system. PHYLUM CNIDARIA

9  Flatworms are the simplest bilateral animals.  Flatworms have organs.  Planarians have a simple nervous system consisting of a brain, sense organs, and branching nerves.  As in cnidarians, the mouth of a flatworm is the only opening for its gastrovascular cavity. PHYLUM PLATYHELMINTHES *ORGAN LEVEL OF ORGANIZATION Digestive tract (gastrovascular cavity) Nerve cords Mouth Eyespots Nervous tissue clusters Bilateral symmetry

10  Flukes and tapeworms are parasitic flatworms with complex life cycles Mature flukes in blood vessels of intestine Human host Male Female Snail host 1 Sexual reproduction of flukes in human; fertilized eggs pass out in feces 2 Eggs hatch in water 3 Larva that infects snail 4 Asexual reproduction of flukes in snail 5 Larva that infects human 6 Larva penetrates skin and blood vessels

11 PHYLUM PLATYHELMINTHES Units with reproductive structures Head Hooks Sucker  Tapeworms can be eaten by cattle and burrow into the intestines and muscles.  If meat is not properly inspected, humans can be infected by eating rare or undercooked beef.

12  Porifera, Cnidaria, and Platyhelminthes lack a body cavity.  Nearly all other animals have a body cavity called a coelom.  This cavity is a fluid-filled space between the digestive tract and the body wall. –The cavity aids in movement, cushions organs, and it may help in circulation. QUICK EVOLUTION CHECKPOINT

13 Body covering (from ectoderm) Muscle layer (from mesoderm) Pseudocoelom Digestive tract (from endoderm) Body covering (from ectoderm) Tissue layer lining coelom and suspending internal organs (from mesoderm) Coelom Digestive tract (from endoderm)

14  AKA: Roundworms  Nematodes have a body cavity not completely lined by mesoderm called a psuedocoelom.  Like most animals, they possess a complete digestive tract.  This is a tube with a mouth and an anus. (One-way tract)  Many nematodes are free-living.  Others are parasites. PHYLUM NEMATODA *PSEUDOCOELOM Trichinella juvenileMuscle tissue

15  Phylum Mollusca is a large and diverse phylum that includes  gastropods, such as snails and slugs  bivalves, such as clams and scallops  cephalopods, such as squids and octopuses PHYLUM MOLLUSCA *COELOM

16  All mollusks have a muscular foot and a mantle  The mantle may secrete a shell which encloses the visceral mass  Mollusks have a true coelom and a circulatory system  Many mollusks feed with a rasping radula PHYLUM MOLLUSCA

17 QUICK EVOLUTION CHECKPOINT: AFTER A BODY CAVITY EVOLVED…  Segmentation is the subdivision of some or most of the body into a series of repeated parts, or segments. Anus Segment walls Excretory organ Digestive tract Coelom Main heart Brain Mouth Accessory heart Nerve cord Blood vessels

18  Segmentation probably evolved as an adaptation for movement

19  Protostomal larval development:  Earliest type of larval development according to evolution  Mouth is the first opening to develop.  Cells of the embryo cannot be altered. QUICK EVOLUTION CHECKPOINT: PROTOSTOMAL LARVAL DEVELOPMENT

20  Earthworms and other annelids are segmented worms whose mouths develop first in the larval stage.  The segmented bodies of annelids give them added mobility for swimming and burrowing.  An earthworm eats its way through soil.  Most leeches are free-living carnivores, but some suck blood. PHYLUM ANNELIDA *BODY SEGMENTATION & PROTOSTOMES

21  Arthropods are the most numerous and widespread of all animals.  They are segmented animals with exoskeletons and jointed appendages. PHYLUM ARTHROPODA *JOINTED APPENDAGES Antennae (sensory reception) CephalothoraxAbdomen Head Thorax Swimming appendages Walking legs Mouthparts (feeding)Pincer (defense)

22  In terms of numbers, distribution, and diversity, they are the most successful phylum of animals.  Diversity:  Insects  Crustaceans (marine arthropods)  Arachnids  Millipedes & centipedes PHYLUM ARTHROPODA Horseshoe crabs are ancient marine arthropods

23  Insects are the most diverse group of organisms.  They have a three-part body consisting of head, thorax, and abdomen.  The development of many insects includes metamorphosis. PHYLUM ARTHROPODA AntennaForewing Mouthparts Hindwing Head ThoraxAbdomen Eye

24  Metamorphosis:  Larvae: specialized for eating and growing  Adults: specialized for dispersal and reproduction PHYLUM ARTHROPODA

25  Echinoderms have spiny skin, an endoskeleton, and a water vascular system for movement.  Phylum Echinodermata includes organisms such as sea stars and sea urchins  These organisms are radially symmetrical as adults PHYLUM ECHINODERMATA *DEUTEROSTOME, ENDOSKELETON, RADIAL SYMMETRY

26  The water vascular system has suction-cup-like tube feet used for respiration and locomotion. PHYLUM ECHINODERMATA Stomach Anus Spines TUBE FEET CANALS

27  Notochord: flexible, tough rod that provides support for the animal and gives muscles a place to attach PHYLUM CHORDATA *NOTOCHORD

28  Organisms in this phylum (LIKE US) are segmented animals with four distinctive features:  Dorsal hollow nerve cord  Stiff notochord  Pharyngeal slits behind the mouth  Muscular post-anal tail PHYLUM CHORDATA *NOTOCHORD

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