Fast Facts - Chapters 32-34 animals General characteristics of animals: - multicellular, heterotrophic eukaryotes - take in food by ingestion - lack cell walls; have cell junctions made of structural proteins that hold cells and tissues together - reproduce sexually; zygote that undergoes cleavage then blastula - followed by gastrulation - rearrange the cells to form a 3 germ layered structure called a gastrula

Fast Facts Bilateral Symmetry - have a top (dorsal), bottom (ventral), head (anterior), and tail (posterior) - have three germ (tissue) layers: triploblastic - ectoderm: forms epidermis of skin and nervous system - endoderm: lining of digestive tract, liver, pancreas - mesoderm: skeletal, muscle, circulatory, and lympatic systems

Animals can also be grouped by the development of a body cavity or coelom - separates the digestive tract from the outer body wall - triploblastic animals can be grouped by the coelom development Acoelomates: - phylum platyhelminthes - no body cavity between the digestive tract and the outer wall - have only one opening; only a gastrovascular cavity - no blood vascular system

Psuedocoelomates: - phylum rotifera and nematoda - have a fluid filled cavity that is incompletely or partially lined with mesoderm -cavity develops between the mesoderm and endoderm Coelomates: - everything else - fluid filled cavity that is completely lined with mesoderm - the digestive tract is suspended in the cavity and held in place with connective tissue called mesentery

Coelomates are further divided according to the pattern of development that their zygote goes through - divided into protosome and deuterosome coelomates Protosome coelomates: - spiral cleavage: during early cell divisions, the divisions are diagonal to the vertical axis of the embryo - cells end up lying between rather than on top of other cells - determinate cleavage: casts the developmental fate of each cell very early

Deuterosome coelomates: - radial cleavage: cells divide at right angles so the cells are above or below each other - first opening becomes the anus, second becomes the mouth - indeterminate cleavage: cells retain ability to develop into complete embryo Four anatomical features characterize the phylum Chordata - notochord, dorsal nerve chord, pharyngeal slits, and a postanal tail

Class Condrichthyes - sharks, skates, and rays - skeleton made of cartilage. Class Osteichthyes - ray finned and lobed finned fish - boney fish; endoskeleton w/ calcium phosphate - 2 chambered heart (1 atria, 1 ventricle)

Fast Facts Sexual reproduction w/ internal fertilization -Oviparous: lay egg, then fertilized; embryo develops within egg after laying - Ovoviviparous: fertilized egg develops in mother, but mother and egg are separated; born live after hatching - Viviparous: live young born; embryo develops inside of body; nourished by placenta

Class Amphibia - means “two lives” - frogs, toads, and salamanders - thought to have evolved from lobed finned fishes - 3 chambered heart (2 atria, 1 ventricle) Class Reptilia - scales are made of keratin (waterproof) - 3 chambered heart (2 atria and 1 partially separated ventricle) - nitrogenous waste excreted as uric acid (low water loss) - internal fertilization; most lay an amniotic egg - ectotherms: obtain heat by external absorption; not “cold blooded”

Development of the amniotic egg allowed animals to move further away from water 4 parts to the amniotic egg - amnion: prevents dehydration and cushions against shock - yolk sac: stockpile of nutrients for the embryo - allantois: disposal sac for metabolic waste - chorion: allows O2 and CO2 to diffuse freely across the egg’s shell - found in birds, reptiles, and mammals

Class Aves - flightless (ratites) and flight (carinate) - thought to have evolved from dinosaurs - body is designed to enhance flight - endothermic: maintain high body temp through metabolism Class Mammalian air-breathing vertebrate animals endothermy, hair, three middle ear bones, mammary glands functional in mothers with young. Most mammals also possess sweat glands and specialized teeth.

Sample Question Structure and function vary across the animal kingdom. Despite this variation, animals exhibit common processes. These include: transport of materials, response to stimuli, gas exchange, and locomotion. For two of the processes above, describe the relevant structures and how they function to accomplish the process in the following phyla - Cnidaria (ex. hydra, jellyfish) - Annelidia (ex. earthworm) - Cordata (ex. mouse)