A.P. Biology Summer Assignment
Coelomate versus Acoelomate Body Plan
Coelomates are organisms that have an internal body cavity lined completely with mesoderm. Acoelomates, on the other hand, either lack an internal body cavity altogether or instead posess a pseudocoelom, a spongocoel, a mesoglea, or a solid layer of mesoderm.
Protosome versus Duetrosome development
Protostome's development begins with the mouth, which develops near or at the blastopore, and is followed by the formation of the anus. Protostomes undergo spiral cleavage, they exude determinate development, they suffer an internal split in their mesoderm independent of the gut, and they take the form of trochophore larva during the larval stage. A deuterostome's development begins with the anus, which develops near or at the blastopore, and whose development is followed by the formation of the mouth. deuterostomes feature radial cleavage and indeterminate development. Mesoderm in deuterostomes tends to occur from characteristic outpocketings of the gut.
In their larval stage, deuterostomes take the form of dipleurula larva.
Radial versus Bilateral symmetry
Radial symmetry is exuded when many different imaginary planes can pass through the long or middle axis of an organism and split it into similar parts. Bilateral symmetry is exuded when only one plane can pass through the long axis of an organism and thus divides the organism into symmetrical right and left sides. The general rule is that Cnidaria and Porifera maintain radial symmetry, while the other phyla retain bilateral symmetry.
Explain how each of these pairs of features was important in constructing the phylogenetic tree shown below. Use specific examples from the tree in your discussion
Porifera and Cnidaria are separate from the rest of the phyla because both Porifera and Cnidaria are radially symmetric, while the rest of the animal Phyla are bilaterally symmetric. The evolutionary development of the...