2. 3.4 The Animal Kingdom eukaryotic and multicellular no cell walls heterotrophic mobile in at least one stage of life reproduce sexually produce an embryo that develops into the significant life stage UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 While 35 phyla make up this rich kingdom, most animals are worms. However, all animals share some characteristics: About 95 percent of animals are invertebrates. (A) Sponges live in aquatic environments, attached to solid surfaces such as rocks, coral, or the shell of another animal. (B) Sea anemones use their stinging tentacles to catch food. (C) Sea cucumbers feed on dead and decaying matter.

3. Characteristics of Animals 95% of animals are invertebrates classified by differences in structure, tissue, and organ organization one to three active or sessile UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 1. Backbone present (vertebrate) or absent (invertebrate) 2. Levels of organization 3. Number of body layers 4. Movement Most animals develop three layers of cells at an early stage in the growth of the embryo. Continued…

4. Characteristics of Animals asymmetrical (no plane of symmetry), radial (symmetrical about any plane with a central axis), or bilateral (symmetrical in one plane) division of body into repetitive sections UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 5. Symmetry and body plan 6. Segmentation Continued… (A) The cnidarian that is known as a hydra shows radial symmetry. (B) The turtle shows bilateral symmetry.

5. Characteristics of Animals UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 (A) Acoelomate animals have flattened bodies. (B) Coelomate animals have a body cavity in which complex internal organs can develop. 7. Body cavity cavity (coelom) present or absent 8. Reproduction asexual or sexual, internal or external fertilization

6. Invertebrate Animals live in both marine and freshwater have an asymmetrical body plan have no tissues have two layers of cells are sessile adults UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Phyla Porifera, Cnidaria, Platehelminthes, Annelida, Echinodermata, and Arthropoda are just a few of the interesting taxa to investigate. Phylum Porifera is better known as the sponges. Sponges: (A) Sponges are animals that have no tissues, no organs, and an asymmetrical body plan. (B) Corals are cnidarians that can form reef environments. Continued…

7. Invertebrate Animals have two cell layers have some tissue organization have radial body symmetry have two body forms: polyp and medusa UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Phylum Cnidaria is an old group and includes hydras, jellyfish, sea anemones, and corals. These organisms: There are two basic forms of cnidarians: polyps and medusae. (A) Polyps, such as adult sea anemones, are sessile. (B) Medusae, like the jellyfish shown in the photo, are mobile. ABAB Continued…

8. Invertebrate Animals have two cell layers have some tissue organization have radial body symmetry have two body forms: polyp and medusa UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Phylum Cnidaria is an old group and includes hydras, jellyfish, sea anemones, and corals. These organisms: There are two basic forms of cnidarians: polyps and medusae. (A) Polyps, such as adult sea anemones, are sessile. (B) Medusae, like the jellyfish shown in the photo, are mobile. ABAB Continued…

9. Invertebrate Animals are acoelomates (no body cavity) have three layers of cells have tissues and a nervous system UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Phylum Platyhelminthes is the flatworm group and includes tapeworms, flukes, and planarians. They: Planarians have a distinct head end that includes eye spots. Continued…

10. Invertebrate Animals have a segmented body have several tissues and organ systems are coelomates (body cavity) UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Phylum Annelida represents the more complex worms, including earthworms. They: Segmented worms, like this earthworm, are coelomates that are segmented on the inside as well as on the outside. Continued…

11. Invertebrate Animals bilateral symmetry three layers of cells a coelom and two body openings a body plan that includes a mantle membrane surrounding internal organs full organ systems UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Phylum Mollusca is diverse and includes all molluscs, for example snails and octopi. They have: Three of the major classes of molluscs are (A) the bivalves, represented here by a file clam; (B) the gastropods, represented by a land snail; and (C) the cephalopods, represented by an octopus. Continued…

12. Invertebrate Animals legs made up of movable, jointed sections segmented bodies with an exoskeleton body plan tissues and organ systems a coelom UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Phylum Arthropoda is the largest phylum and includes spiders, scorpions, crustaceans, and insects. They have:

13. Vertebrate Animals a notochord: a flexible, rod-like structure (replaced by a spine in vertebrates) a dorsal nerve cord UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 The 50 000 species in this phylum, called phylum Chordata, are divided into five major classes: fish, amphibians, reptiles, birds, and mammals. All chordates have two common features that extend the length of the body: Continued…

14. Vertebrate Animals UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Most chordates have an endoskeleton made of bones. Some have only cartilage that is flexible but tough. Some are aquatic; some are terrestrial. Some are known as tetrapods as they have two pairs of limbs. What characteristics indicate pigs belong in phylum Chordata? Continued…

15. Vertebrate Animals UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 The fish superclass is aquatic, and all have gills to obtain oxygen. It includes the oldest living vertebrate: the lamprey, which is jawless and lacks paired fins and a bony skeleton. Some fish have bones (class Osteichthyes) and a swim bladder for vertical movement; others, such as sharks and rays, have cartilage (class Chondrichthyes). (A) The sea lamprey is thought to be the most ancient of all living vertebrates. It is jawless and has a cartilaginous skeleton. This species uses its mouth to hold on to and penetrate the bodies of prey. (B) The cartilaginous fish include the sharks and rays, like this manta. (C) The bony fish include the vast majority of the Earth’s current fish diversity, such as Ontario’s pumpkinseed sunfish. Continued…

16. Vertebrate Animals UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Class Amphibia evolved from bony fish as fins changed into limbs over time. Amphibians are tetrapods and include frogs, toads, and salamanders. They are dependent on wet or moist habitats to survive. Human activity has had a devastating effect on many species in this class. In Ontario, there are representatives of the two major amphibian orders. The bullfrog (A) is an anuran (frogs and toads), and the spotted salamander (B) is a urodelan (salamanders and newts). Continued…

17. Vertebrate Animals UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 The Reptilia class is younger than the amphibian class, with fossils dating back “only” 300 million years. Three orders exist: lizards and snakes, turtles, and crocodilians. Reptiles are not dependent on wet ecosystems because they have evolved body scales that prevent dehydration. They use lungs for gas exchange. Fertilization is internal, and while most lay eggs, some reptiles in colder environments give birth to live offspring. In the three orders, the four major groups of living reptiles are the snakes, lizards, turtles, and crocodilians. The eastern foxsnake (A), five-lined skink (B), and wood turtle (C) are all Ontario residents. The gavial (D) is an endangered species on the Indian subcontinent. Continued…

18. Vertebrate Animals UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 The bird group is called class Aves and may in fact be a modified group of some of the extinct dinosaurs. Some dinosaurs had feathers, like modern birds, while birds have scaled legs, akin to the dinosaurs. Birds are all tetrapods. However, there are important differences. Bird structural and habitat diversity is great. They appeared in the fossil record about 150 million years ago. Most have hollow bones that make them light enough to fly. (A) Black-capped chickadees are small songbirds whose range covers parts of Canada and the United States. (B) Ostriches are large birds that do not fly. They live in desert and grassland regions of Africa. Continued…

19. Vertebrate Animals mammary glands that secrete milk to nourish young hair four-chambered hearts highly developed brains UNIT 1 Chapter 3: Multicellular Diversity Section 3.4 Members of class Mammalia have the following distinctive features:

20. Section 3.4 Review UNIT 1 Chapter 3: Multicellular Diversity Section 3.4