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Explore the biological characteristics and development of animals, including phylogenetic tree, germ layers, body cavities, tissues, and symmetry types. Learn essential body terms and concepts necessary for understanding the anatomy of all animals.
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BIOLOGY II PRE-DISSECTION NOTES
All Animals… • Heterotrophic • Multicellular • Eukaryotic • 95% Invertebrates • 5% Vertebrates
All animals must… • Feed • Respire • Circulate materials • Excrete waste • Respond • Move • Reproduce
Phylogenetic Tree • Drawing that allows the genetic comparison of different phyla • (You should have the drawing you did in class. Keep it for the test.)
Development of Animals • Zygote: fertilized egg • Blastula: hollow ball of cells • Blastopore: opening that develops into the central tube (digestive system) • PROTOSTOME: blastopore becomes the mouth (ex. Most invertebrates) • DEUTEROSTOME: blastopore becomes the anus (ex. Echinoderms, all vertebrates)
Types of Body Cavities • A body cavity allows for specialization • ACOELOMATE: animal with no body cavity (ex. Flatworm) • PSEUDOCOELOMATE: false body cavity, develops between endo and meso (ex. Roundworms) • COELOMATE: animal with a true body cavity, develops completely in mesoderm (Ex. Humans)
Body Tissues • A group of specialized cells that have a common structure and function • Cells group to form tissues • Tissues group to form Organs • Organs group to form organ systems • Organs systems group to form ORGANISMS
Specialized Tissues • Epithelial: lines cavities and covers the outside of the body; protects against invaders, injury and water loss • Connective: connects and supports other tissues; includes bone, cartilage, blood, and threadlike fibers • Muscle: long cells that can contract, most abundant tissue type • Nervous: specialized cells made to sense stimuli and transmit signals
SYMMETRY • The arrangement of body parts around a central point • Asymmetrical: no body arrangement (ex. Sponge) • Radially Symmetrical: body parts radiating out from a central point (ex. Starfish) • Bilaterally Symmetrical: “2 sides”; body parts mirror each other (ex. Butterfly, human)
Body Terms to Know • Anterior: front end of the body; brain usually found here; “head region” • Posterior: tail/ back end of the body • Dorsal: top/back surface of the body • Ventral: bottom/ belly surface of the body