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

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

24.2 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.

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. Water and waste materials are expelled from the sponge through the osculum.

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.

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

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