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| 9179770290 | animal characteristics | - eukaryotic - multicellular; body held together by structural proteins - no cell wall - Cells differentiate and specialize structurally and functionally; have nerve and muscle cells/tissue - heterotrophs - most exist in diploid cell form - most reproduce sexually | 0 | |
| 9179799594 | hox gene | control the expression of many other genes that influence cell division, cell differentiation, and body plan development | 1 | |
| 9179811269 | cleavage | - a diploid zygote and its subsequent daughter cells go through mitosis and divide, but without increasing in size - Cleavage produces a multi-cellular, hollow, ball-shaped embryo called a blastula | 2 | |
| 9179822392 | gastrulation | - Blastula goes through gastrulation to make the gastrula, a more complex embryonic stage - Gastrulation involves the formation of layers of tissue that will develop into specific body parts |  | 3 |
| 9179843375 | origin of animals | - Animals probably evolved from a flagellated protist - First animals probably diverged from a common ancestor with protists about 1 bya - Oldest actual animal fossils found are 575 myo | 4 | |
| 9179851158 | Cambrian explosion | dramatic increase in the number of animal species over a relatively short time (~20 my) | 5 | |
| 9179856304 | hypotheses for Cambrian Explosion | - Evolution of predator - prey relationships - Increase in amount of atmospheric O2 - Evolution of Hox genes controlling development led to more possibilities in body forms | 6 | |
| 9179872677 | Radical Symmetry | - Any slice through central axis divides animal into mirror image halves - Found in sessile animals allowing them to deal with the environment equally from all sides |  | 7 |
| 9179872678 | Bilateral Symmetry | - Only one slice divides animal into equal left & right halves - These animals have dorsal (top)/ventral (bottom) sides, left/right sides, and anterior (head)/posterior (tail) ends - Anterior CNS allows coordination of complex movements. |  | 8 |
| 9179876275 | Protostome Development | spiral cleavage and determinate, blastopore becomes mouth, Schizolcoelous |  | 9 |
| 9179876276 | Dueterostome Development | radical cleavage and indeterminate, blastopore becomes anus, Enterocoelous |  | 10 |
| 9179906816 | Diploblastic | animal embryos have two germ layers: ectoderm & endoderm | 11 | |
| 9179910179 | Triploblastic | animal embryos have three germ layers: ecto, meso, & endoderm | 12 | |
| 9179913321 | ectoderm | layer covering outside of embryo; forms outer covering of animal and central nervous system | 13 | |
| 9179913322 | endoderm | innermost layer of embryo; forms lining of digestive tract, digestive organs, liver, and lungs | 14 | |
| 9179913323 | mesoderm | layer between ecto and endoderm; forms muscles and other organs | 15 | |
| 9179924291 | Body Cavity/Coelom | a fluid-filled space between the digestive tract and outer body wall - Found in some triploblastic animals - Fluid in coelom cushions organs - In some animals, it may contain non-compressible fluid that acts like a skeleton - Allows internal organs to grow and move independently of outer body wall | 16 | |
| 9179939024 | Coelomates | have a "true" coelom formed totally from mesodermal tissue; cavity is lined by mesoderm on all sides |  | 17 |
| 9179945649 | Pseudocoelomates | coelom forms from embryo's blastocoel cavity; outer wall of cavity is a muscle layer (from mesoderm) and inner wall is the digestive tract (from endoderm) |  | 18 |
| 9179952118 | Acoelomates | have no coelom |  | 19 |
| 9180006042 | Enterocoelous | mesoderm on the wall of the archenteron forms pockets that become the coelom |  | 20 |
| 9180027598 | Schizolcoelous | solid masses of mesoderm tissue split and form the coelom | | 21 |
| 9180042994 | Spiral Cleavage | characteristic of protostomes; cells of embryo divide in planes diagonal to vertical axis; cleavage is determinant (a cell's final type is determined early on) |  | 22 |
| 9180050235 | Radial Cleavage | characteristic of deuterostomes; cells of embryo divide in planes parallel or perpendicular to vertical axis; cleavage is indeterminant (early cells each retain ability to become any cell type-even give rise to a new embryo if separated |  | 23 |
