1. The Invertebrates Chapter 25

2. Characteristics of Animals Multicellular Multicellular Heterotrophic Heterotrophic mostly motile mostly motile Sexual and sometimes also asexual repro. Sexual and sometimes also asexual repro. Aerobic respiration to make ATP Aerobic respiration to make ATP No cell walls No cell walls Cells form tissues and organs Cells form tissues and organs

3. Animal Development/Tissues All animals embryos begin as a solid ball of cells. All animals embryos begin as a solid ball of cells. This ball (a blastula) then reorganizes itself into two tissue layers: This ball (a blastula) then reorganizes itself into two tissue layers:

4. Early Tissue Types Ectoderm becomes the epidermis and nervous system. Ectoderm becomes the epidermis and nervous system. Endoderm becomes the gut’s inner lining and the organs derived from it Endoderm becomes the gut’s inner lining and the organs derived from it In higher animals, a mesoderm also forms. This becomes skeleton, muscle and some internal organs. In higher animals, a mesoderm also forms. This becomes skeleton, muscle and some internal organs.

5. The Importance of Body Size Advantages to multicellular body: Advantages to multicellular body: Shelters cells from environmental Shelters cells from environmental Can consume larger food pieces Can consume larger food pieces Able to withstand the loss of some cells Able to withstand the loss of some cells Tissue types can be differentiated to decrease energy expenditure (assembly line approach) Tissue types can be differentiated to decrease energy expenditure (assembly line approach)

6. Choanoflagellates- Choanoflagellates- single celled, heterotrophic, eukaryotes that can live colonially. Protozoans (animal-like protist) Choanoflagellates- single celled, heterotrophic, eukaryotes that can live colonially. Protozoans (animal-like protist) Produce signaling molecules and adhesion proteins which, in animals, help tissues form and stick together. Produce signaling molecules and adhesion proteins which, in animals, help tissues form and stick together. Have a common ancestor with and share some characteristics with sponges. Have a common ancestor with and share some characteristics with sponges.

7. Body Plans Polarity- front and back axis with anterior and posterior ends. Examples: Polarity- front and back axis with anterior and posterior ends. Examples: Radial Symmetry- body parts organized around an axis like spokes. Examples: Radial Symmetry- body parts organized around an axis like spokes. Examples: Bilateral Symmetry- right and left halves. Examples: Bilateral Symmetry- right and left halves. Examples:

8. Cephalization Formation of a head with concentrations of nerve and sensory cells. Formation of a head with concentrations of nerve and sensory cells. May have evolved from colonies of cells with differentiated areas of sensory perception. May have evolved from colonies of cells with differentiated areas of sensory perception. In higher animals, sensory organs and a brain develop as part of cephalization. In higher animals, sensory organs and a brain develop as part of cephalization.

9. Guts and Cavities (sounds appealing, huh?) Some animal digestive systems are “incomplete” with one opening. This sac-like gut was the first to evolve. Examples: Some animal digestive systems are “incomplete” with one opening. This sac-like gut was the first to evolve. Examples: Other digestive systems are “complete” with two openings. Examples: Other digestive systems are “complete” with two openings. Examples: This has several advantages: This has several advantages: Specialized feeding structures Specialized feeding structures Regionally modified tube for digestion and absorption Regionally modified tube for digestion and absorption

10. Complete digestive systems form in two ways: Protostomes- Mouth forms first then anus Protostomes- Mouth forms first then anus Examples: all worm types, arthropods, mollusks (snails, slugs, octopuses) Deuterostomes- Anus forms first then mouth Examples: Echinoderms (sea stars, sea urchins), chordates Deuterostomes- Anus forms first then mouth Examples: Echinoderms (sea stars, sea urchins), chordates

11. Coeloms Coelom- body cavity between the gut and body wall. Coelom- body cavity between the gut and body wall. Peritoneum- lining of the coelom; derived from mesoderm Peritoneum- lining of the coelom; derived from mesoderm All deuterostomes have a coelom; some protostomes have a coelom All deuterostomes have a coelom; some protostomes have a coelom

13. Animals Incomplete Digestive System (Cnidarians, sponges) Complete Digestive System Protostomes (mouth forms first) Acoelomates (no body cavity) Pseudocoelomates (partially lined body cavity) Reduced Coelom Deuterostomes (anus forms first) Coelomates (lined body cavity)

14. SURVEY OF THE INVERTEBRATES Sponges (Phylum Porifera) Sponges (Phylum Porifera) Cnidarians (Phylum Cnidaria) Cnidarians (Phylum Cnidaria) Flatworms (Phylum Platyhelminthes) Flatworms (Phylum Platyhelminthes) Segmented worms (Phylum Annelida) Segmented worms (Phylum Annelida) Mollusks (Phylum Mollusca) Mollusks (Phylum Mollusca) Round Worms (Phylum Nematoda) Round Worms (Phylum Nematoda) Arthropods (Phylum Arthropoda) Arthropods (Phylum Arthropoda) Echinoderms (Phylum Echinodermata) Echinoderms (Phylum Echinodermata)

16. PhylumExamplesEvolutionary Milestone Poriferaspongesmulticellularity Cnidariajellyfish, hydra, coraltissues Platyhelmint hes flatwormsbilateral symmetry Nematodaroundwormspseudocoelom Molluscaclams, squids, snailscoelom Annalidaearthworms, leechessegmentation Arthropoda insects, spiders, crustaceans jointed appendages Echinoderm ata starfishdeuterostomes Chordatavertebratesnotochord

17. Phylum Porifera sponges Assymetrical animals Assymetrical animals Filter feeders Filter feeders No tissues No tissues Motile sperm and larvae Motile sperm and larvae Sessile adult stage Sessile adult stage Spicules of silica in body wall Spicules of silica in body wall Asexual reproduction by budding or fragmentation Asexual reproduction by budding or fragmentation Sexual reproduction by releasing sperm into water. Sexual reproduction by releasing sperm into water.

18. Sponge Body Plan Vocabulary:osculumspiculepore collar cell flagella amoeboid cell

20. Phylum Porifera

21. Phylum Cnidaria jellyfish, corals, sea anemones, etc. Radially symmetrical Radially symmetrical Simplest animals with true tissues (epithelium) Simplest animals with true tissues (epithelium) Tentacles Tentacles Carnivorous Carnivorous Nematocysts- pouches which house barbs for stinging Nematocysts- pouches which house barbs for stinging Two tissue layers but no organs Two tissue layers but no organs Solitary and colonial (corals) Solitary and colonial (corals) Medusa and Polyp body types Medusa and Polyp body types

22. Cnidarian Body Types Polyp body type (coral) Medusa body type (jellyfish)

23. Nematocysts Vocabulary: Operculum Barbs Threads Capsule Nematocyst Cnidocil

24. Highlighted Cnidarian Group Corals Colonial Cnidarian Colonial Cnidarian Calcium carbonate secretions that make “houses” around each polyp shaped animal Calcium carbonate secretions that make “houses” around each polyp shaped animal Dinoflagellate symbionts (photoautotrophs in Kingdom Protista) Dinoflagellate symbionts (photoautotrophs in Kingdom Protista) Coral reefs are the site of tremendous biodiversity in the ocean and are sensitive to pollution and damage. Coral reefs are the site of tremendous biodiversity in the ocean and are sensitive to pollution and damage.

25. Corals Fire Coral Sunflower Mushroom Coral

26. Phylum Platyhelminthes Flatworms (Planaria, Flukes, Tapeworms) Organs! Organ systems! Organs! Organ systems! Organ- two or more tissues that interact in one or more tasks Organ- two or more tissues that interact in one or more tasks Organ systems- two or more organs that interact as they carry out specialized tasks Organ systems- two or more organs that interact as they carry out specialized tasks Three tissue layers- ectoderm, endoderm, and mesoderm Three tissue layers- ectoderm, endoderm, and mesoderm Bilateral, cephalized but with no coelom Bilateral, cephalized but with no coelom Saclike digestive system with pharynx that sucks up and expels Saclike digestive system with pharynx that sucks up and expels Asexual and sexual reproduction. Many are hermaphroditic and some can split by transverse fission. Asexual and sexual reproduction. Many are hermaphroditic and some can split by transverse fission.

27. Platyhelminthes Life Cycle Tape Worm

28. Phylum Annelida Segmented Worms Earth worms, leeches, oligochaetes, polychaetes Earth worms, leeches, oligochaetes, polychaetes Segmented body plan- most segments similar Segmented body plan- most segments similar Tissues, organs, organ systems Tissues, organs, organ systems Closed circulatory system Closed circulatory system Nephridia- units that help collect excess fluid from each segment. Nephridia- units that help collect excess fluid from each segment. Susceptible to fluid loss because of flexible, permeable body covering Susceptible to fluid loss because of flexible, permeable body covering

29. Phylum Annelida

30. Phylum Mollusca Bilateral, soft bodied Bilateral, soft bodied Reduced coelom Reduced coelom Gills as part of the respiratory system Gills as part of the respiratory system Gastropods (snails and sea slugs), Gastropods (snails and sea slugs), Chitons, Chitons, Bivalves (clams, scallops, oysters, mussels) Bivalves (clams, scallops, oysters, mussels) Cephalopods (squid and octopi) Cephalopods (squid and octopi)

31. Mollusks

32. Phylum Nematoda Roundworms Most abundant living animals Most abundant living animals Cylindrical bodies with tapered ends Cylindrical bodies with tapered ends Complete gut Complete gut Most decomposers Most decomposers Some parasites (round worms, pin worms, hookworms, trichinosis) Some parasites (round worms, pin worms, hookworms, trichinosis)

33. Phylum Nematoda

34. Phylum Arthropoda Crabs, spiders, insects Bilateral Bilateral jointed exoskeleton of chitin jointed exoskeleton of chitin specialized appendages specialized appendages Open circulatory system Open circulatory system Reduced coelom Reduced coelom Complete gut Complete gut Molting Molting Specialized stages of development (larvae, juevenile and adult) Specialized stages of development (larvae, juevenile and adult)

35. Phylum Arthropoda (crabs, spiders and insects) Crabs (and lobsters and shrimp) Five pairs of walking legs Five pairs of walking legs Antennae Antennae Food handling appendages Food handling appendages Modified front appendages for mating, defense Modified front appendages for mating, defense

36. Phylum Arthropoda (crabs, spiders and insects) Spiders (and scorpions and ticks) Four of walking legs Four of walking legs Food handling appendages called chelicerae Food handling appendages called chelicerae Predators and parasites Predators and parasites Forebody and hindbody Forebody and hindbody

37. Phylum Arthropoda (crabs, spiders and insects) Insects Most diverse group of animals Most diverse group of animals Segmented body- head, thorax and abdomen Segmented body- head, thorax and abdomen Only winged invertebrates (most successful insects are winged) Only winged invertebrates (most successful insects are winged) Complete digestive system Complete digestive system Metamorphosis (most larvae) Metamorphosis (most larvae) Three pairs of legs Three pairs of legs Antennae Antennae

38. Phylum Echinodermata sea stars, sea urchins, sand dollars spiny-skinned spiny-skinned Plates stiffened with calcium carbonate Plates stiffened with calcium carbonate Marine Marine Radially symmetrical Radially symmetrical Tube feet as part of a water vascular system Tube feet as part of a water vascular system Predators Predators Closest relatives of the chordates (us) Closest relatives of the chordates (us)

39. READ CHAPTER 26 READ CHAPTERS 25 and 26 to be prepared for next week Quiz on chapter 25 next week. Lecture on chapt. 26 Lab Practical NEXT WEEK!!!!