2.   Organelle → one of several formed bodies with specialized functions suspended in the cytoplasm of a cell.  Cell → smallest single unit that exhibits properties of life  Tissue → a collection of similar, specialized cells grouped together to carry out a specific function (separated by membranous layers)  Organ → a specialized center of body function composed of several different types of tissues  Organ system → a group of organs that work together to perform vital body functions  Organism → an individual living thing What makes an animal?

3.  Further Characterizing Animals  Organism → an individual living thing  Population → a group of the same species living in the same area  Community → interacting populations that exist in the same area  Ecosystem/Biome → living and nonliving factors that exist in a particular region or environment  Biosphere → all life on earth

4.   Body Plan → the set of morphological and developmental traits that are generally integrated into a functional whole Symmetry Tissues Body cavities Early embryonic development Characterizing animals…

6.   Asymmetry → completely lacking symmetry  Radial symmetry → symmetry around the center with many equal parts radiating outward  Bilateral symmetry → symmetry that bisects the body in to equal but opposite halves  Dorsal = top  Ventral = bottom  Anterior = head  Posterior = tail Symmetry

7.   Tissues are derived from germ layers.  Germ layers differentiate in a process called gastrulation.  3 basic types:  Ectoderm → surface layer  Develops external cells (epidermis = skin)  Endoderm → innermost layer  Develops the cells of the digestive system  Mesoderm → layer between ectoderm and endoderm  Develops muscle, organ and connective tissue cells Tissues

8.   Eumatazoans → animals that develop true tissues  Diploblasts → develop two germ layers, endoderm and ectoderm  Triploblasts → develop all three germ layers, endoderm, ectoderm, and mesoderm Tissues continued…

9.   Body cavity → fluid filled space separating the digestive tract from the outer body wall, also known as a coelom.  Coelom → meaning “hollow” refers to the body cavity formed from mesoderm.  3 types of coelomates (animals possessing a true body cavity) 1.Acoelomates 2.Pseudocoelomates 3.Colemates Body Cavities

10.   Triploblasts  Lack a body cavity between the digestive cavity and outer body wall. Acoelomate

11.   Have a body cavity only partially lined by tissue derived from mesoderm. Psuedocoelomate

12.   Have a true body cavity completely lined by tissue derived from mesoderm. Coelomate

13.  Early Embryonic Development Protostome  Spiral cleavage of cells  Coelom develops from the split of mesoderm from endoderm  Mouth develops from first opening, anus from the second Deuterostome  Radial cleavage of cells  Coelom develops from the mesoderm budding or pocketing from endoderm  Anus develops from first opening, mouth from the second

14.  Protostome vs. Deuterostome

15.   Phylogeny → the evolutionary history of a species or a group of related species.  Cephalization → an evolutionary trend toward the concentration of sensory equipment on the anterior end of the body.  Digestion → complete (mouth to anus) vs. incomplete (gastrovascular cavity)  Niche → the ecological position or function of an organism in the environment.  Chordate (phylum Chordata) → animal that has a (1)notochord, (2)dorsal hollow nerve cord, (3)pharyngeal slits or clefts, and a (4)muscular, post-anal tail.  Invertebrate (subphylum) → animal lacking a backbone.  Vertebrate (subphylum) → animal with a brain enclosed by a skull or cranium and a segmented spinal column. Vocabulary