Download Body Plans and Adaptations 25

Body Plans and Adaptations
25-2
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Objectives and Vocabulary
• Objectives:
1. Compare and contrast
radial and bilateral
symmetry with
asymmetry.
2. Trace the phylogeny of
animal body planes.
3. Distinguish among the
body plans of
acoelomate,
pseudocoelomate and
coelomate animals.
• Vocabulary:
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Symmetry
Radial symmetry
Bilateral symmetry
Anterior
Posterior
Dorsal
Ventral
Acoelomate
Pseudocoelom
Coelom
Exoskeleton
Invertebrate
Endoskeleton
Vertebrate
What is Symmetry?
• The arrangement
of body
structuresDifferent kinds of
symmetry enable
animals to move
about in different
ways.
Symmetry link
• https://video.search.yahoo.com/search/video;
_ylt=AwrSbnL38blXSuEA9ZlXNyoA;_ylu=X3oD
MTE0ZHQwOXYwBGNvbG8DZ3ExBHBvcwMxB
HZ0aWQDQjE3MjJfMQRzZWMDcGl2cw-?p=activiies+that+illustrate+symmetry+animal
s&fr=hp-ddc-bd&fr2=pivweb#id=4&vid=e4bdea0335d025b02d6f9b9cd
499ced9&action=view
Asymmetry
• An animal that is irregular
in shape with no
symmetry has an
asymmetrical body plan.
• Tend to be sessile
organisms that do not
move from place to place.
• Sponges for example: 2
layers of cells lacking the
endoderm and mesoderm
or the gastrula stage of
development.
Group assessment
•What is asymetry
and give an
example?
Radial Symmetry
• Animals with this body plan
can be divided along any plane
through a central axis, into
roughly equal halves.
– Hydra for example- tentacles
radiate out from around its
mouth
• This type of symmetry is an
adaptation that enables an
animal to detect and capture
prey coming toward it from
any direction.
• Develops from 2 embryonic
cell layers ectoderm and
endoderm.
Radial Symmetry
• This type of symmetry is
an adaptation that
enables an animal to
detect and capture prey
coming toward it from
any direction.
• Develops from 2
embryonic cell layers
ectoderm and
endoderm.
Group assessment
•What is Radial
symmetry and give
and example?
Bilateral Symmetry
• Butterfly for example
– Divided in half only along
one plane- similar right and
left halves.
• Anterior or head end, has
sensory organs
• Posterior or tail end
• Dorsal or upper
surface(back side) also
looks different from the
ventral or lower
surface(belly).
Bilateral Symmetry
• Develop from 3
embryonic cell layersecto, endo and
mesoderm
• Some animals have
fluid-filled spaces called
body cavities that
internal organs are
found
Bilateral Symmetry
• This development of
fluid-filled body cavities
made it possible for
animals to grow larger
because it allowed for
the efficient circulation
and transport of fluids
and support of organs
and organ systems.
Examples of different types of
symmetry
Group assessment
•What is bilateral
symmetry and give
an animal example?
Acoelomates
• Animals that develop
from 3 cell layers- but
no body cavities
– Digestive tract that
extends throughout
the body
– May have been the
first group of animals
in which organs
formed
Acoelomates
– Flatworms
• Organs are
embedded in solid
tissues
• A flattened body and
branched digestive
tract allow for the
diffusion of nutrients,
water and oxygen to
supply all body cells
and eliminate waste
Group assessment
•What is a
Acoelomate and
give an example?
Pseudocoelomates
• Roundworm
– Unlike a flatworm,
the body of
roundworms has a
space that develops
between the
endoderm and
mesoderm called
pseudocoelom which
is a fluid-filled cavity
partly lined with
mesoderm
Pseudocoelomates
• Has a mouth to
take in food,
middle section
to break it
down and anus
to expel wastes
Group assessment
•What are
Pseudocoelomates
and give an
example?
Coelomates
• Earthworm, Human,
Fish, Insects and others
– Body cavity develops
from a coelom- fluidfilled space that is
completely
surrounded by
mesoderm
– Specialized organs
and organ systems
Coelomates
• Digestive tract and
other internal organs
are attached by
double layers of
mesoderm and
suspended within
the coelom which
also provides
support and
cushions them
Comparison between coelomates,
Pseudocoelomates, Acoelomates
Comparison between coelomates,
Pseudocoelomates, Acoelomates
Group assessment
•What are
coelomates and give
and example?
Animal Support and Protection
• Exoskeleton
– Hard covering on the
outside of the body
that provides a
framework for
support
– Also protects soft
body tissues,
prevents water loss
and protection from
predators
Animal Support and Protection
– Provides a place for
muscle attachment
– As the animal grows
it sheds the old
exoskeleton and
secretes a new one
– Found in
invertebrates: crabs,
insects, spiders
Animal Support and Protection
• Endoskeleton
– Found in other
invertebrates like
sea urchins, and
sea stars
– Provides support
– Protects internal
organs
Animal Support and Protection
• May be made of
calcium
carbonate(sea stars);
cartilage(sharks);
bone(bony fishes,
amphibians, reptiles,
birds, mammals)
Vertebrates
• With a backbone
– Bilaterally symmetrical
Group assessment
• What is the difference
between an endoskeleton,
exoskeleton and vertebrate
and give an example of
each?
Questions 25.2
• 1. Compare and Contrast radial and bilaterial
symmetry in animals and give and example of each?
• 2. Compare and contrast the body plan of an
acoelomate and a coelomate and give an example of
an animal for each one?
• 3. Explain how an adaptation such as an exoskelten
could be an advantage to animals in land biomes?
• 4. Compare movement in acoelomate and
coelomate animals?