Animals pt 1 Flashcards
anterior
head region
posterior
tail region
dorsal
back or top
ventral
abdomen or bottom
Symmetry
Balance in body proportions
Asymmetrical Symmetry
Irregular Shape
Radial Symmetry
Can be divided along any plane to produce 2 equal halves
Bilateral
Can be divided only one way to produce mirror image halves
Body Development
As embryo develops, 3 germ layers form
3 germ layers form in body development
Ectoderm, Mesoderm, Endoderm
Ectoderm
becomes nervous system, epidermis of the skin, pituitary, lens of eye
Mesoderm
becomes muscles, skeleton, notochord, circulatory system, kidney, reproductive system
Endoderm
becomes lining of digestive tract, liver, pancreas, epithelial lining of lungs, many endocrine glands
Examples of Acoelmates
sponges, cnidarians, & flatworms
Pseudocoelmates
partial body cavity lined with mesoderm
“Tube within a tube” body plan
Example of Pseudocoelmates
roundworms
Coelomates
true body cavity lined with mesoderm
Example of Coelomates
All other animals
Cephalization
concentration of sense organs- developed nervous system
Protostomes
Blastopore becomes the mouth. Ex-Annelids, Mollusks and arthropods
Deuterostomes
Blastopore becomes anus. Ex-Chordates
Characteristics of Animals
- Multicellular, eukaryotes
- Heterotrophs
- Cells w/out cell walls, many have specialized functions
- Usually have a method of movement
- Most reproduce sexually
- Require oxygen
Acoelmates
No body cavity lined with mesoderm