Chapter 24 Introduction to Animals Section 1 Animal

Chapter 24 Introduction to Animals Section 1: Animal Characteristics Section 2: Animal Body Plans Section 3: Sponges and Cnidarians Click on a lesson name to select.

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics General Animal Features § The ancestral animals at the beginning of the evolutionary tree are eukaryotic and multicellular. § They developed adaptations in structure that enabled them to function in numerous habitats.

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics Feeding and Digestion § Animals are heterotrophic. § The structure or form of an animal’s mouth parts determines how its mouth functions.

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics Support § Invertebrates § Exoskeletons § Hard or tough outer coverings that provide a framework of support § Protect soft body tissues § Provide protection from predators

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics Support § Vertebrates § Endoskeletons § Protect internal organs § Provide support for the body § Provide an internal brace for muscles to pull against

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics Movement § The evolution of nerve and muscle tissues enables animals to move in ways that are more complex and faster than organisms in other kingdoms.

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics Reproduction § Fertilization occurs when the sperm penetrates the egg to form a fertilized egg cell called the zygote. § Internal fertilization § External fertilization

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics § Asexual reproduction means that a single parent produces offspring that are genetically identical to itself. § Budding § Fragmentation § Regeneration § Parthenogenesis

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics Early Development § The zygote undergoes mitosis and a series of cell divisions to form new cells. § The cells continue to divide, forming a fluidfilled ball of cells called the blastula. § The blastula continues to undergo cell division as some cells move inward to form a gastrula.

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics

Chapter 24 Introduction to Animals

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics Tissue Development § Endoderm § inner layer of cells in the gastrula § Ectoderm § outer layer of cells in the gastrula § Mesoderm § layer of cells between the endoderm and ectoderm

Chapter 24 Introduction to Animals 24. 1 Animal Characteristics

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans Evolution of Animal Body Plans § Anatomical features in animals’ body plans mark the branching points on the evolutionary tree. § Relationships on this tree are inferred by studying similarities in embryological development and shared anatomical features.

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans Symmetry § Similarity or balance among body structures of organisms § Asymmetry § Radial symmetry § Bilateral symmetry

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans Cephalization § The tendency to concentrate nervous tissue and sensory organs at the anterior end of the animal

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans Body Cavities § Coelomates § Have a fluidfilled cavity with tissue formed from mesoderm that lines and encloses the organs in the coelom

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans Body Cavities § Pseudocoelomates § Have a fluid-filled body cavity that develops between the mesoderm and the endoderm rather than developing entirely within the mesoderm

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans Body Cavities § Acoelomates § Have solid bodies without a fluid-filled body cavity between the gut and the body wall

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans Development in Coelomate Animals § Protostomes § The mouth develops from the first opening in the gastrula. § Deuterostomes § The anus develops from the first opening in the gastrula. Visualizing Protostome and Deuterostome Development

Chapter 24 Introduction to Animals 24. 2 Animal Body Plans Segmentation § Segmented animals can be “put together” from a succession of similar parts. § Can survive damage to one segment § Movement is more effective

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Sponges § Sponges do not develop tissues. § Collar cells with flagella line the inside of the sponge and whip back and forth drawing water into the body of the sponge. § Water and waste materials are expelled from the sponge through the osculum.

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians

Chapter 24 Introduction to Animals

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Filter Feeder § Food particles cling to the cells. § Digestion of nutrients takes place within each cell.

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Archaeocytes § Specialized cells that secrete spicules, which are the support structures of sponges § Spicules are small, needlelike structures made of calcium carbonate, silica, or a tough fibrous protein called spongin

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Sponge Diversity § Demospongiae § Calcarea § Hexactinellida

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Reproduction § Reproduce asexually § Fragmentation § Budding § Gemmules § Reproduce sexually § Eggs remain within a sponge. § Sperm are released into the water.

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians § Have one body opening and two layers of cells § Outer layer functions in protecting the internal body § Inner layer functions mainly in digestion

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Feeding and Digestion § Tentacles are armed with stinging cells called cnidocytes. § A nematocyst is a capsule that holds a coiled tube containing poison and barbs. § Water inside an undischarged nematocyst is under an osmotic pressure of more than 150 atmospheres.

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians § As the osmotic pressure increases, the nematocyst discharges forcefully. § A barb is capable of penetrating a crab shell.

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians § Cells lining the gastrovascular cavity release digestive enzymes over captured prey. § Undigested materials are ejected though the mouth.

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Response to Stimuli § A nerve net conducts impulses to and from all parts of the body. § The impulses cause contractions of musclelike cells in the two cell layers.

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Reproduction § Two body forms § Polyp § Medusa

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians § The two body forms of cnidarians can be observed in the life cycle of jellyfishes.

Chapter 24 Introduction to Animals

Chapter 24 Introduction to Animals 24. 3 Sponges and Cnidarians Cnidarian Diversity § Hydroids § Jellyfishes § Sea anemones and corals

Chapter 24 Introduction to Animals Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Questions Standardized Test Practice biologygmh. com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding lesson.

Chapter 24 Introduction to Animals Chapter Diagnostic Questions Which animal is not an invertebrate? A. lobster B. shark C. cicada D. earthworm

Chapter 24 Introduction to Animals Chapter Diagnostic Questions What is the tough outer covering of most invertebrates called? A. exoskeleton B. endoskeleton C. endoderm D. mesoderm

Chapter 24 Introduction to Animals Chapter Diagnostic Questions Which statement is not true of animals? A. Animal cells have cell walls. B. Animals are heterotrophic. C. Animals probably evolved from protists. early D. Animal cells become tissues.

Chapter 24 Introduction to Animals 24. 1 Formative Questions From which organisms might animals have evolved? A. animal-like bacteria B. autotrophic invertebrates C. colonial protists D. multicellular fungi

Chapter 24 Introduction to Animals 24. 1 Formative Questions What is a group of cells that performs a specific function? A. organ B. tissue C. gastrula D. mesoderm

Chapter 24 Introduction to Animals 24. 1 Formative Questions What is one of the most unique characteristics of the animal kingdom? A. advanced cell structure B. complex movement C. sexual reproduction D. organ development

Chapter 24 Introduction to Animals 24. 1 Formative Questions What is the term for an individual animal that produces both eggs and sperm? A. acoelomate B. hermaphrodite C. heterosexual D. invertebrate

Chapter 24 Introduction to Animals 24. 1 Formative Questions What form of reproduction produces a new organism from the lost body part of another organism? A. budding B. fertilization C. parthenogenesis D. regeneration

Chapter 24 Introduction to Animals 24. 2 Formative Questions Which provides the strongest evidence for the relationship between arthropods and roundworms? A. shared anatomical features B. shared functional characteristics C. similar protein structure D. similar embryological development

Chapter 24 Introduction to Animals 24. 2 Formative Questions Which is the dorsal surface of a hummingbird?

Chapter 24 Introduction to Animals 24. 2 Formative Questions Which organism exhibits cephalization? A. jellyfish B. snail C. sponge D. starfish

Chapter 24 Introduction to Animals 24. 2 Formative Questions How is deuterostome development different from protostome development shown here?

Chapter 24 Introduction to Animals 24. 2 Formative Questions A. A blastula does not form. B. The coelom is less advanced. C. The gut is lined with mesoderm. D. The blastopore becomes the anus.

Chapter 24 Introduction to Animals 24. 3 Formative Questions Why are sponges most distantly related to the rest of the animals? A. They are not multicellular. B. They do not have true tissues. C. Their embryos have a mesoderm. D. They arose from a different ancestor. protist

Chapter 24 Introduction to Animals 24. 3 Formative Questions What is the term for organisms that remain attached to one place? A. sessile B. tactile C. axiallary D. sedentary

Chapter 24 Introduction to Animals 24. 3 Formative Questions What provides the energy for the discharge of a cnidarian’s nematocysts? A. muscle fibers B. hydraulic forces C. osmotic pressure D. protein springs

Chapter 24 Introduction to Animals 24. 3 Formative Questions Which is the dominant stage in the life cycle of a sea anemone? A. bud B. hydroid C. medusa D. polyp

Chapter 24 Introduction to Animals Chapter Assessment Questions Identify the term that is used to describe the evolutionary history of a particular species. A. genealogy B. biology C. phylogeny D. paleontology

Chapter 24 Introduction to Animals Chapter Assessment Questions Distinguish between asymmetry, radial symmetry and bilateral symmetry and give an example of each.

Chapter 24 Introduction to Animals Chapter Assessment Questions Answer: Asymmetry – There is no symmetry or balance in body structure and no shape. Example: sponge Radial symmetry – The animal’s body can be divided along any plane through a central axis into equal halves. Example: jellyfish Bilateral symmetry – The animal can be divided into mirror image halves along one plane. Example: dog

Chapter 24 Introduction to Animals Chapter Assessment Questions Explain why it would be beneficial for a fish to lay many eggs when fertilization is external. Answer: Some of the eggs will float away, be eaten or destroyed, so laying a large number of eggs makes it more likely that some will be fertilized and hatch.

Chapter 24 Introduction to Animals Standardized Test Practice Which is not a characteristic that defines all animals? A. carnivorous B. eukaryotic C. heterotrophic D. multicellular

Chapter 24 Introduction to Animals Standardized Test Practice At which stage is the developing animal an embryo?

Chapter 24 Introduction to Animals Standardized Test Practice Which reproduces by internal fertilization? A. bear B. clam C. fish D. frog

Chapter 24 Introduction to Animals Standardized Test Practice What is the most recent evolutionary development exhibited by both arthropods and echinoderms? A. a body cavity B. a coelom C. segmentation D. protostome development

Chapter 24 Introduction to Animals Standardized Test Practice Which organisms are most closely related to roundworms? A. sponges B. cnidarians C. flatworms D. arthropods

Chapter 24 Introduction to Animals Standardized Test Practice What characteristic do sponges and cnidarians have in common? A. body symmetry B. single body opening C. cell layers organized into tissues D. sessile attachment to surfaces

Chapter 24 Introduction to Animals Glencoe Biology Transparencies

Chapter 24 Introduction to Animals Image Bank

Chapter 24 Introduction to Animals Vocabulary Section 1 invertebrate external fertilization exoskeleton endoskeleton vertebrate hermaphrodite zygote internal fertilization blastula gastrula endoderm ectoderm mesoderm

Chapter 24 Introduction to Animals Vocabulary Section 2 symmetry ventral radial symmetry bilateral symmetry anterior posterior cephalization dorsal coelom pseudocoelom acoelomate protostome deuterostome

Chapter 24 Introduction to Animals Vocabulary Section 3 filter feeder polyp sessile cnidocyte nematocyst gastrovascular cavity nerve net medusa

Chapter 24 Introduction to Animals Animation § Cell Differentiation in Animal Development § A Sponge § A Cnidarian § Visualizing Protostome and Deuterostome Development