Chapter
32
Animations
Study Guide
Unit 5: The Evolutionary History of Diversity
An Introduction to Animal Diversity
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.
Summary:
Chapter
33
Animations
Study Guide
Unit 5: The Evolutionary History of Diversity
Invertebrates
Review
Invertebrates
do not have a
, and account for 95% of known
animal
species.
Phyla
and
are the multicellular
sponges
(formerly Porifera) that lack true tissues. Fertilization is external:
Phylum
belongs in the
clade
with true
called
.
Most Eumetazoa belong to the clade
and exhibit
symmetry and
triploblastic
embryonic development.
Phylum
are flatworms with a gastrovascular cavity.
Phylum
are roundworms with a
.
Phylum
are tiny animals, smaller than many protists.
Phylum
are soft-bodied
animals.
Phylum
are segmented worms with a true
.
Phylum
have
bodies.
Phylum
are
.
Summary:
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