BIO 124 Lecture Notes - Lecture 22: Cambrian Explosion, Dorsal Nerve Cord, Symmetry In Biology
16 Mar 2016
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No cell wall: can have interesing cellular matrix but no rigid cell wall & are usually lexible. Acive movement: more rapid and acive in movement. Diversity of form: variaion in size, but most are invertebrates. Diversity of habitat: inhabit basically all places (except really extreme environments) o o. Wide distribuion - both marine and terrestrial (mostly marine) Almost all sexual reproducion = haploid gametes fuse to form zygote. Embryonic development = divides number of imes without growing in size (cleavage) and creates ball of cells (blastula) o o. Blastula: in most animals guts which is important to process. While there"s a lot of excepions, but in general animals are mobile, diverse in shape, size, habitat, reproducion & development. Chemical fossils of animal speciic steroids from late proterozoic (710 ma) Anatomically an animal - ediacaran fauna was what appeared to be irst animal. Animal diversity: basal animals let us see anatomical basic structure: metazoa, porifera: sponges.
