Animal Characteristics

Animal Traits Multicellular Complex patterns of development Single-celled zygote to multicellular adult Heterotroph Internal processes Break down materials from the environment Ingest food into internal gut Most animals move Specialized muscle tissue & body plan

Animal Body Plans Body plan Integrated functioning of its parts Four key features Symmetry Structure of the Body cavity The Segmentation External Appendages

Body Plan Symmetry Asymmetrical Spherical Symmetry Radial Symmetry No plane of symmetry Spherical Symmetry Body parts radiate out a central point Radial Symmetry One main access body parts are arranged Bilateral Symmetry Mirror image Animals that move

Body Cavities Coelom Internal body cavity fully lined with mesoderm Body organs suspended in this cavity

Body Cavities Acoelomate animals Pseudocoelomate animals have solid bodies filled with cells Pseudocoelomate animals have a functional body cavity NOT fully lined with mesoderm

Body Plan Structure Body cavities act as a hydrostatic skeleton Acoelomate (ex. Flatworm) Lack enclosed, fluid filled body cavity Space between gut Pseudocoelomate Pseudocoel – fluid-filled space where internal organs are suspended Enclosed by muscle No mesoderm surrounding internal organs Coelomate Coelom – body cavity that develops within the mesoderm Lined with peritoneum (muscular tissue) Body cavities act as a hydrostatic skeleton Invertebrate animals

Body Plan Segmentation Bodies divided into segments Allows animals to alter the shape of its body

Body Plan Appendages Enhance locomotion Tube feet Specialized limbs Obtain food, avoid predators, find mates Tube feet Move slowly across the substratum Specialized limbs Highly controlled, rapid movement Jointed limbs Arthropods

How Animals Get Their Food Filter feeders Capture small organisms delivered by their environment Air, water Straining device to filter the food Can be motile or sessile

How Animals Get Their Food Herbivores eat plants Feed on plants Usually without killing them Long, complex guts to digest

How Animals Get Their Food Predators Capture & subdue large prey Sensitive sensory organs to locate prey Sharp teeth/claws Some have toxins

How Animals Get Their Food Parasites Live in a host & consumes parts of the organism Endoparasites Live inside host Ectoparasites More morphologically complex

How Animals Get Their Food Detritivores/ Scavenger Feed on dead organic material

Movement Sessile Sedentary Motile Attached & non-moving sponges Sedentary move very little clam Motile Animals that can move; Have muscular tissue to provide energy for movement copyright cmassengale

SESSILE SEDENTARY Chiton Sponge MOTILE Cheetah copyright cmassengale

Reproduction All animals are capable of sexual reproduction Some reproduce asexually Hermaphrodites produce both egg & sperm Hermaphrodites may exchange sperm and NOT fertilize their own eggs Parthenogenesis Females produce eggs, but the eggs develop without being fertilized New offspring will be all female

Parthenogenesis in the Komodo Dragon copyright cmassengale

Developmental Patterns Zygote (fertilized egg) undergoes rapid cell divisions called cleavage Forms a hollow ball of cells called the blastula copyright cmassengale

Developmental Patterns Cleavage First few cell divisions of a zygote Cell divisions without cell growth the cytoplasm is divided into smaller and smaller cells, called blastomeres Cleavage Patterns Influenced by the amount of the yolk (nutritive material- nourishes the embryo)

Developmental Patterns Gastrulation Hollow ball 1 cell thick forms cup-shape Blastopore Opening of the cavity Becomes the mouth (protostomes) OR Becomes the anus (deuterostomes) layers of an embryo are formed and the body plan of the mature organism is established

Embryonic Development copyright cmassengale

Germ Layers Form tissues, organs, & systems Ectoderm (outer) NOT present in sponges Ectoderm (outer) forms skin, nerves, sense organs Endoderm (inner) forms liver and lungs Mesoderm (middle) forms muscles & other systems copyright cmassengale

Major Groups of Invertebrates Web-quest http://www.can-do.com/uci/lessons98/Invertebrates.html