Invertebrate Evolution:
- As animals became larger and more complex, specialized cells joined together to form tissues, organs, and organ systems that work together to carry out complex functions.
- All invertebrates except sponges have some type of body symmetry ( radial or bilateral)
- Invertebrates with cephalization can respond to the environment more quickly than simpler vertebrates.
- Most invertbrates with bilateral symmetry also have segmented bodies, which over evolution have often become specialized for specidic functions.
- Most animal phyla have a true coelom that is lined completel with mesoderm
- Worms, arthropods and mollusks are protostomes, and echinoderms are deuterostomes.
Vertebrate Evolution:
This derived characteristics increased complexity over the course of evolution of the vertebrates:
- Bilateral symmetry
- Two pairs of jointed locomotor appendages, which can include fins (pectoral and anal/dorsal fins, as well as the forelimbs and hindlimbs)
- Outer covering of protective cellular skin, which can be modified into special structures such as scales, hair and feathers
- Metamerism found in skeletal, muscular and nervous system. - structures can include ribs, vertebrae, muscles and ganglia/peripheral nerves.
- Well-developed coelom, or body cavity
- Well-developed internal skeleton
- Cephalization
- Specialized systems ( circulatory, respiratory, reproductive...)
For a better view of the charts visit: http://mail.esdnl.ca/~greg_kent/S05937F3B.32/u02_s04_notes_kingdom_animalia.pdf
