Animals: Welcome to Your Kingdom Basic Form and Function

What is an Animal? Invertebrates and Vertebrates Multicellular Heterotrophic Eukaryotic Contain Tissues that develop from germ layers

Nutritional Mode of Animals Heterotrophic: Ingestion of food and absorption inside digestive tract with aide of enzymes Plants: autotrophic Fungi: heterotrophic that grow on or near that feed by absorption Often aided by enzymes that digest food outside of bodies

Cellular Organization of Animals Multicellular but lack cellular support through cell walls Instead held together by structural proteins (most abundant is collagen) Cells are specialized into functional Tissues then organs, etc. Muscular, nervous, etc. Tissues develop from layers of cells during diploid stage of developmental life cycle (germ layers)

Phylogeny of the Animal Kingdom Vertebrates live here, in the phylum of Chordates…but not all Chordates are vertebrates…

What is a chordate? There are 4 morphological structures that appear during some point during the animal’s lifetime: Notochord – long flexible tube in between digestive tube and the nerve cord becomes gelatinous material between vertebrae in humans Dorsal nerve cord becomes CNS in humans Pharyngeal slits (gill slits) Muscular post-anal tail – most chordates have a tail that extends beyond the anus

Survey of Vertebrate Classes Fishes: Agnatha, Chondrichthyes, Osteichthyes Tetrapods: Amphibia, Reptilia, Aves, Mammalia Amniotes: Reptilia, Aves, Mammalia

Class Agnatha Sample organisms: Jawless vertebrates Hagfishes, lampreys Jawless vertebrates Feed by sucking blood after clamping onto prey or by scavenging Do not have paired appendages or paired fins Cartilaginous Skeleton

Class Chondrichthyes Sample organisms: sharks and rays Cartilaginous fishes – have relatively flexible skeletons made of cartilage rather than bone Most sharks are carnivorous and have acute senses Have jaws

Class Osteichthyes Bony fishes Sample organisms: perch, trout Have hard skeletons (due to ossification) Sample organisms: perch, trout Breathe by drawing water over 4-5 pairs of gills covered by operculum (protective flap) Most bony fishes are oviparous Females lays large numbers of eggs, fertilization occurs externally

Class Osteichthyes

Class Amphibia The first vertebrates (tetrapods) on land Amphibians must deposit their shell-less eggs in water so they don’t dry out Sample organisms: frogs & salamanders Amphibian = “two lives” Tadpole – larval stage Metamorphosis occurs Frog – legs develop Salamanders – have tails Frogs – do not have tails

Class Reptilia Sample organisms: lizards, snakes, turtles, crocodiles Reptiles have scales made of keratin that cover their skin Obtain oxygen with their lungs Fertilization occurs internally Most reptiles lay amniotic eggs on land Ectotherms – body temperature fluctuates with the environment

Class Aves Birds are tetrapods with feathers Their forelimbs are modified as wings Sample organisms: owl, sparrow, penguin, eagles Lay amniotic eggs Endothermic – regulate their own body temps. Anatomy adapted for flight Form & function

Class Mammalia Mammals have hair Endothermic Mammary glands that produce milk Most mammals are born, not hatched Three major groups: Monotremes – lay eggs platypuses Marsupials – complete development in a maternal pouch Kangaroos, koalas, opossums Placental mammals – complete development within the uterus, joined to the mother by the placenta Sheep, bats, elephants, humans