Unit 5: The Evolutionary History of Diversity
Extras
Study Guide
Chapter 32
9
Review
Animals are multicellular,
eukaryotes
that ingest their food.
The ancestor of animals
diverged
from those of
about 1.2 billion-800 million years ago, and may have resembled
modern
.
The kingdom diversified about 525 million years ago, during the
explosion,
when many animal phyla
appeared
.
Animals can be categorized by how their cells are organized according to a
plan
.
symmetry
is like a flower pot, the body radiates from the center.
symmetry
has a single plane of symmetry.
Most animals have
that develop from embryonic
layers
of the
.
Diploblastic
animals such as
jellyfish
have
germ layers:
and
.
Triploblastic
animals have
germ layers,
including
a
.
The mesoderm may develop into tissue that line a fluid-filled
space
called a
.
A
is a body
cavity
only partially lined by mesoderm tissues.
Organisms without a body
cavity
are considered
.
The coelomates show two major modes of
development.
Protostomes develop their
from the blastopore of the
gastrula
.
Deuterostomes develop their
from the
blastopore
.
Current phylogeny places
as a clade with true
, and divides the Bilateria into three
clades:
,
Lophotrochozoa
, and
Ecdysozoa
.
Review and exercise:
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May 2, 2012
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