AGRC1020 Lecture Notes - Lecture 3: Body Cavity, Neoproterozoic, Diploblasty
30 Jul 2018
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Reproduction cells have diploid stage undergoes cleavage. Many animals have at least one larvae stage (sexually immature) Most animals have hox genes regulate development of body form. Ediacaran fossil animals are the earliest known macroscopic animals. Cambrian explosions marks earliest fossil appearance of many groups of living animals. Animals began to make an impact on land by 460 million years ago. Animals can be categorised by symmetry or lack of. Mass extinctions of both terrestrial and marine animals. A dorsal (top) side and a ventral (bottom) side. Radial animals are often sessile or planktonic (drifting or weakly swimming) Bilateral animals often move actively and have a central nervous system. Body pla(cid:374)s vary a(cid:272)(cid:272)ordi(cid:374)g to orga(cid:374)isatio(cid:374) of a(cid:374)i(cid:373)al"s tissues. E(cid:272)toder(cid:373) is the ger(cid:373) layer (cid:272)overi(cid:374)g the e(cid:373)(cid:271)ryo"s surface. Endoderm is the innermost germ layer and lines the developing digestive tube, called the archenteron. Sponges and a few other groups lack true tissues.
