Chapter 24 Introduction to Animals Section 1: Animal Characteristics Section 2: Animal Body Plans Section 3: Sponges and Cnidarians

General Animal Features 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.

Animals are heterotrophic. 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.

Hard or tough outer coverings that provide a framework of support 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

Protect internal organs 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.

Internal fertilization 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 fluid-filled ball of cells called the blastula. The blastula continues to undergo cell division as some cells move inward to form a gastrula.

24.1 Animal Characteristics Chapter 24 Introduction to Animals 24.1 Animal Characteristics

Chapter 24 Introduction to Animals

inner layer of cells in the gastrula 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

24.1 Animal Characteristics Chapter 24 Introduction to Animals 24.1 Animal Characteristics

Evolution of Animal Body Plans 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

24.2 Animal Body Plans Symmetry 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

Have a fluid-filled cavity with tissue formed from mesoderm Chapter 24 Introduction to Animals 24.2 Animal Body Plans Body Cavities Coelomates Have a fluid-filled cavity with tissue formed from mesoderm that lines and encloses the organs in the coelom

Have a fluid-filled body cavity that develops between the mesoderm and 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

Body Cavities Acoelomates 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

Development in Coelomate Animals 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

Can survive damage to one segment 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

Sponges do not develop tissues. 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.

24.3 Sponges and Cnidarians Chapter 24 Introduction to Animals 24.3 Sponges and Cnidarians

Chapter 24 Introduction to Animals

Food particles cling to the cells. 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

Sponge Diversity Demospongiae Calcarea Hexactinellida Chapter 24 Introduction to Animals 24.3 Sponges and Cnidarians Sponge Diversity Demospongiae Calcarea Hexactinellida

Eggs remain within a sponge. 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.

Have one body opening and two layers of cells Chapter 24 Introduction to Animals 24.3 Sponges and Cnidarians Cnidarians Have one body opening and two layers of cells Outer layer functions in protecting the internal body Inner layer functions mainly in digestion

Tentacles are armed with stinging cells called cnidocytes. 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.

A barb is capable of penetrating a crab shell. 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.

Undigested materials are ejected though the mouth. 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.

A nerve net conducts impulses to and from all parts of the body. 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.

Reproduction Two body forms Polyp Medusa 24.3 Sponges and Cnidarians 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

Sea anemones and corals Chapter 24 Introduction to Animals 24.3 Sponges and Cnidarians Cnidarian Diversity Hydroids Jellyfishes Sea anemones and corals

Chapter Resource Menu Chapter Diagnostic Questions 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.

Which animal is not an invertebrate? Chapter 24 Introduction to Animals Chapter Diagnostic Questions Which animal is not an invertebrate? lobster shark cicada earthworm

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

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

From which organisms might animals have evolved? Chapter 24 Introduction to Animals 24.1 Formative Questions From which organisms might animals have evolved? animal-like bacteria autotrophic invertebrates colonial protists multicellular fungi

What is a group of cells that performs a specific function? Chapter 24 Introduction to Animals 24.1 Formative Questions What is a group of cells that performs a specific function? organ tissue gastrula mesoderm

What is one of the most unique characteristics of the animal kingdom? Chapter 24 Introduction to Animals 24.1 Formative Questions What is one of the most unique characteristics of the animal kingdom? advanced cell structure complex movement sexual reproduction organ development

What is the term for an individual animal that Chapter 24 Introduction to Animals 24.1 Formative Questions What is the term for an individual animal that produces both eggs and sperm? acoelomate hermaphrodite heterosexual invertebrate

What form of reproduction produces a new 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? budding fertilization parthenogenesis regeneration

Which provides the strongest evidence for Chapter 24 Introduction to Animals 24.2 Formative Questions Which provides the strongest evidence for the relationship between arthropods and roundworms? shared anatomical features shared functional characteristics similar protein structure similar embryological development

Which is the dorsal surface of a hummingbird? 24.2 Formative Questions Chapter 24 Introduction to Animals 24.2 Formative Questions Which is the dorsal surface of a hummingbird?

Which organism exhibits cephalization? Chapter 24 Introduction to Animals 24.2 Formative Questions Which organism exhibits cephalization? jellyfish snail sponge starfish

development different from protostome development shown here? Chapter 24 Introduction to Animals 24.2 Formative Questions How is deuterostome development different from protostome development shown here?

A blastula does not form. The coelom is less advanced. Chapter 24 Introduction to Animals 24.2 Formative Questions A blastula does not form. The coelom is less advanced. The gut is lined with mesoderm. The blastopore becomes the anus.

Why are sponges most distantly related to the rest of the animals? Chapter 24 Introduction to Animals 24.3 Formative Questions Why are sponges most distantly related to the rest of the animals? They are not multicellular. They do not have true tissues. Their embryos have a mesoderm. They arose from a different protist ancestor.

What is the term for organisms that remain attached to one place? Chapter 24 Introduction to Animals 24.3 Formative Questions What is the term for organisms that remain attached to one place? sessile tactile axiallary sedentary

What provides the energy for the discharge Chapter 24 Introduction to Animals 24.3 Formative Questions What provides the energy for the discharge of a cnidarian’s nematocysts? muscle fibers hydraulic forces osmotic pressure protein springs

Which is the dominant stage in the life cycle of a sea anemone? Chapter 24 Introduction to Animals 24.3 Formative Questions Which is the dominant stage in the life cycle of a sea anemone? bud hydroid medusa polyp

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

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

Answer: Asymmetry – There is no symmetry or 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

Explain why it would be beneficial for a fish to 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.

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

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

Which reproduces by internal fertilization? Chapter 24 Introduction to Animals Standardized Test Practice Which reproduces by internal fertilization? bear clam fish frog

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

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

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

Glencoe Biology Transparencies Chapter 24 Introduction to Animals Glencoe Biology Transparencies

Chapter 24 Introduction to Animals Image Bank

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

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

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

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