Body Plans and Adaptations A;_ylu=X3oDMTE0ZHQwOXYwBGNvbG8DZ3ExBHBvcwMxBHZ0aWQDQjE3MjJf MQRzZWMDcGl2cw--?p=activiies+that+illustrate+symmetry+animals&fr=hp- ddc-bd&fr2=piv- web#id=4&vid=e4bdea0335d025b02d6f9b9cd499ced9&action=view

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: – Symmetry – Radial symmetry – Bilateral symmetry – Anterior – Posterior – Dorsal – Ventral – Acoelomate – Pseudocoelom – Coelom – Exoskeleton – Invertebrate – Endoskeleton – Vertebrate

What is Symmetry? The arrangement of body structures- Different kinds of symmetry enable animals to move about in different ways.

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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 layers- ecto, 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- fluid- filled 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

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 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?