Multicellular and Tissue Levels of Organization
A. Levels of Organization in Organismal
Complexity
1. Zoologists recognize ________ major
phyla of living multicellular
animals.
2. Major body plans are the result of extensive
________________
and are a limiting determinant of future
______________________
variants.
3. Animal share structural complexities
that reflect common
______________________.
II. Hierarchical Organization of Animal Complexity
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Hierarchical rankings |
Examples of animals with this complexity |
Animal groups of this complexity |
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A. Grades of Organization
1. Unicellular ______________________
groups are the simplest
animal-like organisms.
a. Within the cell, they perform all
basic functions.
b. ______________________ is achieved by
varying
architectural patterns of subcellular
structures, organelles
and the whole cell.
2. ______________________ are multicellular animals.
a. Cells become specialized parts of a
whole organism;
these cells cannot live alone as do protozoan cells.
b. Simplest metazoans show a cellular
grade of
organizations and are not strongly associated to perform a
collective function (e.g. _____________________).
3. More complex metazoans have a
______________________
grade organization
with cells working closely together as a unit.
4. Many tissues work together in an
organ; most metazoans
operate at the ______________________level.
B. Complexity and Body Size
1.
Small animals
a. BENEFITS –
b. COSTS –
2.
______________________________________________ noted
that lineages began with small individuals and eventually
evolved
toward giant forms; it holds for nonflying
vertebrates and many
invertebrates.
3.
More complex grades of metazoan organization permit and
promote evolution of large body size.
a. Surface area increases are the square
of body length,
volume is the cube of body length.
b. A large animal has
______________________ surface
area compared to its volume, than does a smaller animal.
c. Flattening or infolding
the body increases surface area, as
in flatworms.
d. Most animals had to develop internal
transports systems
to shuttle nutrients, gases and waste products, as they
became larger.
4. Benefits of Being Large
III. Extracellular
Components of the Metazoan Body
A. Body fluids and extracellular
structural elements are noncellular
components of metazoan animals.
1. In contrast to intracellular fluids, extracellular fluids are outside
the cells.
2. Blood plasma and interstitial fluid
are part of the extracellular
fluids in open and closed circulatory systems.
B. Architectural Extracellular
Structural Elements
1. Loose connective tissue is well-developed
in vertebrates.
2. Cartilage is found in molluscs and chordates.
3. Bone is found in vertebrates.
4. Cuticle is pervasive in arthropods,
nematodes, annelids and
others.
C. Types of Tissues (______________________ is the
study of types of
tissues)
1. ______________________ Tissue
a. Epithelium is a sheet of cells that
covers an internal or
external surface.
b. It provides outside protection and
internal linings, often
modified to produce lubricants, hormones or enzymes.
c. Simple epithelia are found in all metazoa.
d. Stratified epithelia are restricted to
vertebrates.
2. ______________________ Tissue
a. Connective tissues are nearly
everywhere in the body.
b. It is made up of few cells, many extracellular
______________________ and
a ground substance or
______________________.
c. In vertebrates, there are two types of
connective tissue
proper.
d. Much fibrous tissue is made of protein
______________________, the most abundant
protein in
the animal kingdom.
e. Connective tissue also includes blood,
lymph and tissue
fluid.
f. ______________________ is semirigid connective tissue
with closely packed fibers embedded in a gel-like matrix.
g. ______________________ is calcified
connective tissue
with calcium salts organized around collagen fibers.
3. ______________________ Tissue
a. Muscle is the most abundant tissue in
most animals.
b. The cell is the muscle
______________________,
specialized for contraction.
d. ______________________ muscles include
skeletal and
cardiac muscles.
1) Skeletal muscle is ______________________
2) Cardiac muscle is ______________________
e. Smooth muscles lack the alternating
bands seen in
striated muscle.
1) Always ______________________
f. Myofibrils are contractile elements
and the unspecialized
cytoplasm is sarcoplasm.
4. Nervous Tissue
a. Nervous tissue receives and conducts
____________________________________________.
b. Nervous tissue cell types are
______________________
that receive & conduct the impulse and
_____________________ that support the neurons.
IV. Animal Body Plans
A. Animal Symmetry
1. ______________________ symmetry occurs
when any plane
divides the body into mirrored halves, as in cutting a globe
in half.
2. ______________________ symmetry occurs
when any plane
passing through the longitudinal axis divides the body into
mirrored
halves, as in cutting a pie. These animals are examples of the
Radiata.
a)
the ______________________ (e.g. hydra,
jellyfish &
corals)
3. ______________________ symmetry occurs
in an animal that
is radial except for some paired feature that allows
only two
mirrored halves. Another example of Radiata.
a) ______________________ (e.g. comb jellyfish)
4. In ______________________ symmetry,
an organism can be
cut in a sagittal plane into
two mirror halves; this usually provides
for a head (______________________) in bilateral animals
classified in the ______________________.
B. Body Regions
1. ______________________ indicates
the head end; the opposite
or tail end is ______________________.
2. ______________________ is the
back side and
______________________ is the
front or belly side.
3. ______________________ is on
the midline of the body;
______________________ is to the
sides.
4. ______________________ parts
are far from the body;
______________________ parts are near.
5. A ______________________ plane divides
the body into dorsal
and ventral halves.
6. A ______________________ plane divides
an animal into right
and left halves.
7. A ______________________ plane (or
cross section) separates
anterior and posterior portions.
8. In vertebrates, ______________________
is the chest region or
area supported by the forelegs.
9. ______________________ refers
to the hip region or area
supported by the hind legs.
C. Body Cavities
1. The Coelom
a. The major evolutionary innovation of Bilateria is the
coelom.
b. The ______________________ is a
fluid-filled space
around the gut; it provides a tube-within-a-tube
arrangement
with greater flexibility.
c. A coelom
provides more space for organs and surface
area for exchange.
d. Worms rely on the coelom
for a
____________________________________________ to
aid in burrowing.
2. Acoelomate Bilateria – 3 phyla, the ______________________,
______________________, &
______________________
a. Acoelomate
animals lack a body cavity surrounding the
gut.
b. Internal regions are filled with
mesoderm and a spongy
mass of parenchyma from ectodermal
cells.
c. Sometimes, parenchymal
cells are cell bodies of muscle
cells.
3. Pseudocoelomate
Bilateria – 9 phyla including
______________________ &
______________________
a. Nematodes and some others have a
cavity around the gut
but it is derived from the ______________________ of the
embryo.
b. It provides a tube-within-a-tube but
it is not derived from
mesoderm.
4. Eucoelomate Bilateria – all other complex animals
a. A true coelom
is lined with mesodermal peritoneum.
b. It is formed in one of two methods but
both produce a
mesodermal peritoneum.
D. ______________________ (Segmentation)
1. Metamerism
is serial repetition of similar body segments.
2. Each segment is a metamere
or ______________________.
3. True metamerism
is found in ______________________,
______________________ and
______________________; other
groups show a superficial segmentation.
E. Cephalization
1. Differentiation of the head, or
______________________, is
mainly found in bilaterally symmetrical animals.
2. Concentrating the sense organs at the
head, as well as the
mouth, is efficient for sensing and responding to the
environment
and food.
3. Polarity is the gradient in activities
between anterior and
posterior ends.